Comparing Thermostatic and Electronic Master Mixing Valves for Domestic Hot Water

the broadcast is now starting all attendees are in listen-only mode oh hi welcome to coffee with coffee thanks for joining us today our presenter today Kevin freed desired Director of Product Management and pound-for-pound probably that one of the best product management folks you you'll run into out there and that he's going out on the road a bit these days so hopefully you'll have a chance to to meet him someday and he's put together a great webinar he puts a lot of time and effort into this I think it'll show as we go through it and you know I've noticed I go to webinars and I've done a lot of webinars myself and they're kind of like a steers horn to get a few good points with a lot of bull in between but that's not going to be the case today with Kevin so hopefully you'll enjoy this and let us know what you think and the hydraulics that's what we're up to issue number 23 is on the street if you were getting these and they stopped coming just go and sign up again make sure these that keep coming to you because there's a lifetime of information and every one of these issues so they're available and as you can see down at the bottom there's our website we can go and get the PDF copies of those also and keep them under Dropbox or something like that so the folks out in the field can use those for the job site and I get you know what we want to from you folks if you could is input on some other topics here's a topic set we're gonna be clear the issues that kind of go with the topic that Kevin's going to be covering today but we're always looking for more you know topics to cover in the future so let us know if there's something on your mind we'll work on that so I think that might be all the housekeeping yeah take it away Kevin thanks thanks Bob I appreciate it can you hear me yep sounds great all right let's talk about today's topics we'll discuss differences in designs performance accuracy things like proper piping flow rates we'll look at some specifications and requirements that are different from thermostatic to electronic master valves talk about recirculation and balancing that's a really interesting and information-packed section of the PowerPoint and we'll touch on service and maintenance and then lastly we want to talk about thermal disinfection you know raising the temperature to kill Legionella bacteria that's near the end of the presentation so all right so at a high level you know 50,000 feet here are some things that you might think of when you think of what are the differences what are the main differences between thermostatic and electronic valves what comes to mind here is first of all cost in general a thermostatic valve is going to be less you know that might not always be true but in general the the that will hold true ease of installation and familiarity you know lots of these are installed out there like approaching a million right Bob and people are very familiar with thermostatic valve so so that's that's a simple simple one ability to handle scale this is an interesting topic an electronic valve gets the nod there because there are some models out there that can actually do a periodic sweep or a rotation of the valve seat to flush away scale and we'll touch on that too minta max flow range in general an electronic valve can handle maybe a lower men and a higher max and we'll look at that too and we'll talk about recirculation temperature creep this this comes up a lot we get a lot of questions about creep what is it how do we prevent it and then we'll talk about you know the added functionality alarming remote access and electronic valves get that not as well so before we get into the meat and potatoes we actually have a poll question here we'd really like it if everyone could answer this poll question for plumbing applications have you ever specified or installed thermostatic mixing valves electronic mixing valves both or neither yet so I'll pause for a few minutes and let everybody enter their vote you know I won't run this for about 30 seconds but we're just trying to get a feel for for what's being used out there and how much traction these new EMV electronic mixing valves are getting in the market that's big good information for us to have so we'll make sure we're on the right page as we develop this product so there we go thermostatic mixing valves at 47 percent EMV is lectronimo Canal is only 2 percent mmm both 39 percent and need at 13% Kevin hmm that is interesting thanks everybody for doing that let's let's get into it so the first thing we need to do is define define what is a master mixing valve so we all know what we're talking about here so it is a point of distribution valve so if you look at this schematic here this particular schematic has an electronic master mixing valve so this is at the point of distribution which means it's located near the hot water supply these valves are governed primarily by a standard called a SSE 1017 and this is the cover of it and a couple of quotes that describe what it is okay these this standard describes the point of distribution valve and it also says there in that second bullet that you need to be providing also point-of-use or in-line devices to prevent scald protection and do final control the way I remember that is ASSE 10 17 comes before 1070 and those point-of-use valves are 1070 let's take a look at just one slide to look at what is this what is this standard it's interesting there's basically three tests in this standard and the first one is a conditioning test so what they do is run the valve with 200 degree water and 125 psi for six hours that's that's a kind of a torture test to begin with just to make sure the valve doesn't leak or blow up or or you know fail in any way the main part of the test is a temperature control test and so what they do is provide 140 degree hot supply the cold supply water is whatever is available and the inlet inlets are set at 45 psi that's the cold and hot inlets and the outlet at 35 so there's a 10 psi difference across the valve and they set it for a hundred and ten degrees setpoint and then at that point what they do is look at the actual water and that table shown down below is the accuracy so depending on the flow of the valve they make sure that it's plus or minus three degrees if you're in that low flow range of three to five GPM and you can be plus or minus five degrees in the middle range and then plus or minus seven degrees at the high range so what they're really doing there is defining the accuracy that the valve needs to needs to handle to pass the test and then they reduce it reduce the flow by half and increase the hot water supply by twenty-five degrees and the valve in during these changes it has to be stable within those temperature variations there and then it will pass the test that part of the test and lastly they do a hydrostatic press pressure test and pump it up to 500 psi for five minutes and make sure it doesn't blow up so that's really the test that is used to qualify a point of distribution valve alright let's let's let's cut this thing open and see what's inside of a thermostatic master mixing valve now this is pretty typical for any brand that's out there but mainly there is this I call it a thermostatic motor so there's gold this gold part right here that the the arrow is pointing to that is a sealed element and it's filled with a special wax compound that's heat sensitive and what it does it expands and contracts and causes this linear motion up and down right here so as it heats up and expands what it does is move this cylinder or this cartridge right in the middle of the body here up and down to then proportionally mix the hot and cold water coming in so as the as the element is warm it expands and as it cools off it contracts than to mix that water now what's important for stable control is that you have well mixed water around that motor if you have laminar flow or really low flow coming in through those ports then you can envision that that thermal motor might be hot on one side and cold on the other and at very low flows that can happen and then the valve can be unstable that element might not be sure what to do if it's hot on one side and cold on the other so it's important to have enough velocity and well mixed water around that around that motor and so that shaft is connected like I said to the cartridge and it opens and closes those inlet ports in proportions so as that stem moves up and down it's opening and closing the cold ports pretty much proportionally the set point you can kind of see that here in the cutaway it actually is connected to a spring that then changes the force that opposes that thermostatic motor movement so that the the the temperature indications on the dial are calibrated to correspond to the movement of that of that thermal motor and that's how it works to maintain temperature one thing to note is that the mixing port never closes okay it's always proportioning between the hot and the cold and the mix is always the same opening that's why it'll have a cv of for example three now I got a really interesting pre-submitted question here that applies to this how would you pipe a two temperature system when you need hot water direct from the heater and tempered water to the fixtures that's a really great question so what the what this question is is suppose we needed to pull some hot water off of this piping between the mixing valve and the heater for something like a commercial dishwasher or a washing machine you know can you do that answer is yes but what that will do is it'll cause a pressure difference between the hot and the cold ports so you have to be you have to be aware of that and if you have much of a pressure difference between the hot and cold port then the valve will struggle to control a stable mixed outlet so that's when you have to use check valves if you have something tied in to eat actually either side something tied in near the cold side or near the hot side then you want to have those check valves in there because you can imagine if you popped open a solenoid valve to feed a washing machine it could actually draw cold water from that cold and let through the and then backwards through that hot port and it's just flow going the wrong way and these valves are self-contained they don't require any electricity they are you know just do what they're they do what they do and that's pretty simple let's look in the land at an electronic master mixing valve now this sample is just a globe type valve there are there are other types of alb but the difference between an electronic and a thermostatic in this one it's it's linear also so the stem right here moves up and down that's similar to a thermostatic mixing valve and inside if we look at this cutaway what we'll see up in the stem area or the bonnet of the valve are some packing seals and the ones I'm familiar with have a Teflon type of what's called a V ring and they wipe the stem and typically these stems are stainless steel and so those packing seals keep the stem clean as it moves up and down and this example here if you look there's two inlets there's an A Inlet on the left and a B Inlet on the bottom and there's two seats there so that plug has a seat mating surface on the bottom and then another mating surface on the top so as the stem moves up and down again it proportionally changes the flow for the two inlets to the outlet now most I don't know most but but a lot of globe valves have metal to metal seats what that means is there's no soft seating surface in there and now a metal to metal seat is going to have some amount of leakage and we're going to talk about that and in just a minute another kind of electronic master mixing valve or valve type is a rotary or a 3-way ball valve now here's a cutaway of the Caliph eligio mix so rather than being linear it's rotary so the stem rotates 90 degrees and up in the stem area typically you'll have a rings so as the stem rotates it rotates within the o-ring seals and that ball will rotate I know if you can really see it here but there are rings on the edges of the ball here and that's where the seal is provided on a ball valve that's rotating so both of these types no matter what kind of electronic master mixing valve you have they require some sort of proportional or floating control actuator they have to modulate so a proportional actuator would be of 0 to 10 volt or 2 to 10 volt or perhaps a 4 to 20 mili-amp proportional type signal or a floating which is a three wire drive one-way Drive the other way signal those are all modulating and to and to do mixed temperature control you have to modulate so that's the actuator you also require a controller something needs to tell the actuator what to do and that is in this case there's the controller for the Liege amix and you have to have a sensor in the mixed outlet so in this picture you can see that sensor next to the gauge is screwed into the outlet adapter there and that sensor is wired to the controller which then tells the actuator what to do here's a here's a flow chart or a diagram that I like to use so in in the mixed water is a temperature sensor as the water temperature changes that sensor will send a signal back to the controller as an analog input and within the controller is some type of a control algorithm now this might be a proportional integral or a PID PID proportional integral derivative type of algorithm but what that does is compares the set point that you've programmed in the control to the value coming back from the sensor it looks at the amount of error in that signal and then decides what kind of a modulating signal to send out to the actuator which then positions the valve which then changes the next water temperatures of this is a closed loop control system just a very really basic look at how that works now in this picture to notice this sensor right here the Collegium product has a return sensor now this is used when we do thermal disinfection to to kill Legionella so I wanted to just point that out that's not really typically required for doing normal mixed control it does give you the value but it's used in the control logic for for thermal disinfection some of the differences in specifications I mentioned earlier the thermostatic valve is just standalone doesn't require any electricity or electrician or anything like that I want to talk about failsafe or Spring return that question actually comes in quite a bit when we're talking about the electronic mixing valve so the Coletti product that you see on the right does not have a physical spring so it's not it's not spring return doesn't have a fail-safe mode when you remove power failsafe is a term that I use if you have a super capacitor or some other type of electronic technology in the actuator you can do the same thing as a spring return does it's just an electronic way to position the valve in the event of loss of power how important is that in a master mixing valve it's a good point of discussion if you lose power in the building your research pumps going to turn off everything's going to turn off and so then if you have water draw at a fixture that valve is just going to be sitting in the last position is that bad don't you know don't know it depends either way we highly recommend using a UPS or an uninterruptible power supply on anything that's critical such as an electronic master mixing valve what about accuracy I mentioned earlier in in the discussion on a SSE 1017 that as long as you pass these temperature variations then then you're approved to a SSE 1017 so that's doable with a thermostatic or an electronic valve it's not actually that difficult to maintain that kind of accuracy now accuracy some folks will say that an electronic valve is more accurate it certainly can be and it can be faster depending on how you program it and whether you use the PID program or some other algorithm you can actually change and control the speed of response but really the accuracy depends a lot on the valve type the mechanical side of the valve the design and in combination with the actuator and the controller so all of them together will affect the accuracy so really you know just check this the literature the datasheet on the individual products that are out there for that accuracy and of course they're all going to say three percent or better because they have to to pass ASSA 10:17 what about the sensors I mentioned that thermal motor that integral wax element in the thermostatic valve really basic now mixed electronic valves will use maybe a thermistor or an RTD or some other type of electronic sensing sensing device they're all going to have to meet the low-lead laws for North America and see NSF 372 is the one that covers governs products used in and drinking water so all the products that you are able to buy to do this are going to meet that law one of the questions came in what about sizing the valve is there a different approach or a different way to size a thermostatic valve compared to an electronic valve and the answer is dull what you're really looking at is you know the demand in the building so you might use a table like this that discusses fixture units or there's information in the uniform plumbing code or you know I atmo has this water demand calculator so whatever you're currently used to size you know for the demand is is good for either a thermostatic or electronic no different what about a user interface you know how do you look at a thermostatic valve well you really just have the dial setpoint right so the you know Man 2 valve interface is really just a physical dial and you may or may not have a temperature gauge to provide you with feedback there really that's all there is of course with the standalone thermostatic mixing valve but you know electronically everything opens up right the world is available to you so there are a lot of products out there that have LED LCD user interfaces a lot of advantages to going with this okay first of all you can set an exact set point you know you can set it for a 120 if you want and with a dial you're getting as close as you as you think you can there are a variety of configuration options local and remote indication of temperatures and status and everything just like any other electronic product and of course that gives you web access integration to a building automation system it's it's wide open there really depends on on the product that's available get into a little more technical detail here let's talk about close off what I'm talking about here is the inlet ports the hot and cold inlet ports most thermostatic valves are not designed to close off 100% on those two inlets and that's not a problem some you know what we'll call flow through is actually pretty normal and if you're thinking about just regular mix temperature control it's really not an issue the the thermal element will move up and down and mix the water as it needs to to maintain setpoint um now that can become a problem and we're going to discuss this a detail later when we're talking about recirculation and temperature creep so we'll wait and get to that gets at that point another thing to note is that metal to metal seat globe valves will have some flow through there's actually an ANSI standard that's called a leakage standard and there's like class 1 class 2 class 3 class 4 whenever you have a metal to metal seat you're not going to get a what's called a bubble tight close off so that means that a globe valve that has a metal to metal seat could still allow temperature creep in a research system most ball valves just by the nature of the ball and the seals are what are referred to as bubble tight so there's no flow through what that means is that the hot port will close 100% and the cold port will close tight as well so you know that means it means a couple of things first of all you eliminate creep and we're going to get into that too but something else to think about is if they can close off tight then they can operate on less of a differential temperature from hot to mixed compared to a thermostatic valve if you look at a spec sheet for a thermostatic valve you might see something like minimum temperature difference between hot and mixed equals 18 degrees or 27 degrees okay that's something that becomes less of a concern when you have a valve that will close off tight what about capacity a lot of people asked about capacity so let's let's spend some time on this the capacity of the valve depends on the type of the body and the design internally so here's a table that shows just some references three different pipe sizes one one and a half and two inch a typical maximum cv for a thermostatic valve you can see they're three to seven maybe twelve maybe sixteen on the two-inch and when you go to the different types of valves the flow capacity changes a lot a spool or a cage type valve or a cartridge type valve generally they're a little higher you can see that these numbers are higher than the thermostatic and a global valve you know twelve maybe for a CV on a one inch maybe thirty and then 45 on a two-inch those are if you look across the industry those are pretty typical maximum Seabees but the ball valve look at that that the CV the maximum CV for ball valve is significantly higher now why is that ball valve will have higher flow capacity because they have lower pressure drop the larger effective area you know through the internal side of the valve allows for more flow and lower pressure drop so what that actually means is there could be cases where you could use one ball valve where you might need two of the other types of Valve's to meet a certain maximum GPM requirement you know if you're on the bubble there with with the GPM maximum here's a graph for a typical thermostatic valve this is actually the Collette 521 so what we want to talk about here is flow range for the thermostatic the maximum flow that you're going to get through a thermostatic mixing valve is really based on what I refer to as a reasonable pressure drop what does that mean if you have too much flow through any restriction or too high of a pressure drop no matter what it is you're going to be looking at potential noise maybe maybe some cavitation maybe some erosion so what we suggest in our collective products is to try and stay at a maximum of about 20 psi D through a thermostatic mixing valve now you can go a little higher and you can you know periodically but what so what we're talking about is right up here in the graph so if you go higher than that you're just asking for problems and if you go a little higher and get a little bit of noise if you back down okay not a big deal but this is a guideline and this is what we recommend the minimum flow on a valve like this is really based on the control stability remember I mentioned earlier this whole issue of laminar flow and that you need a nice mixed turbulent water flow around the thermal motor to keep it stable that's basically how we determine the minimum and that really is determined in the lab by empirical testing it really depends on the design of the valve and so there's that statement about you know well mixed water and you need a differential between hot and mixed I mentioned that earlier too so a thermostatic mixing valve needs to have temperatures to work with okay it needs a a good hot temperature that's significantly higher than your mixed outlet setpoint and it needs the cold water to work well so this valve right here I mentioned the 20 psi D maximum here we are right here at the top of the range so in terms of what we recommend this is pretty much the maximum and that would correspond to around 15 GPM I feel if you come down here on the x axis and this valves been tested and we know that it performs very well down at about 1 GPM minimum so it will actually work lower than that but we know that right in this range right here or a point 1 psi pressure drop across our 521 series mix Callie it works great so this is the flow range of this valve that has a CB of 3 and there's the equation that we use to determine flow based on CV and pressure drop so what if we need more than 1 to 15 GPM in a master mixing valve here's a product that we have that is we call a high-low thermostatic valve and what it does if you look down here this is the 521 mix Cal right here so there's a three quarter inch mix Cal the one we just looked at on the graph that's this valve down here here's the big brother of that the mix Cal Plus this is an inch and a quarter valve and what we have here is these are piped in parallel but right downstream of the big valve is a PR V and when the capacity the flow through this assembly starts to get up around the maximum range of this little valve this pressure drops right here at the PRV will fall off and then open the port so the big valve kicks in so they work together in a in a staging kind of a relationship and this assembly right here will deliver one GPM 250 GPM so remember we looked at the valve by itself it was 1 to 15 now we're looking at 1 to 50 in this high-low assembly so that's a very very good approach a lot of these out there a lot of people build their own we make this just like you see it here and ships in a box ready to go what about the flow range for an electronic valve generally the ranges are higher so let's look at this graph here the kalevi valve that you see here in a one inch has a minimum of three and a maximum of 94 here's the inch and a quarter so 4.4 GPM to 107 now these max flow ranges are based on that 20 psi drop that I mentioned earlier that applies to everything and that's our recommendation so that you'll notice too that the minimums are a little bit higher well yeah that's that's that's the nature of a modulating valve like this now one thing to know though is that whenever you're using one of these valves you're probably going to be looking at a recirculation system so if you have a recirc pump in this commercial application generally it will fulfill these minimums so if your research pump is running 3 GPM then essentially with this one-inch valve you have a minimum flow of 0 draw from the fixtures that will still be within the control range of the valve the maximum flow again is going to follow that same rule you know like I mentioned 20 psi D is a good rule of thumb at least for our products you'll see literature out there that says max differential 65 psi in and and that's just amazing really who is going to put 65 psi D across a master mixing valve that's that's kind of insane the minimum flow will depend on the valve type and the valve design really the literature is going to tell you any of those electronic master mixing valves out there will tell you what they're minimums are and that just is based on the capability of the valve to provide good range ability from maximum to minimum flow switch gears a little bit let's talk about piping when a mixing valve does not have tight closed off so here's a here's a schematic that shows a thermostatic mixing valve and let's assume that this valve has a little bit of flow through on the hot port and the cold port what can happen is you can get temperature creep let me tell you what that is in any recirculating hot water distribution system okay there will be times when the circulator is operating and there's no water being drawn at the fixtures so you can look at this as being a closed loop condition if there's no draw you cannot add additional cold water what that means is you have to maintain that recirculating hot water temperature using just the returned water okay and if you have a little bit of flow through on that hot port then you can get creep and what what happens is if more heat is being added to that recirc loop then is being given up by the supply piping to the ambient air then you get creep because you're adding more heat to the piping then you are removing from the piping so if you think about that if your piping is well insulated which it should be then the chance of creep is greater if the piping is not well insulated and you have a lot of heat loss in that supply line from the valve out to the fixtures you get a lot of heat loss to ambient then maybe a little bit of flow through at the hot port will not cause creep but that really all depends on what's going on in the installation so what you have to do to prevent that is add this bypass valve right here this little valve right here number one this return valve is kind of optional but what you have to do is put this valve and right here and what that does is excuse me let me go back that throttles the amount of water that can go back to the tank so what you do is you close this down almost all the way and that really minimizes the amount of research water that can be added back into the tank which then means that very little water will be coming out here and going into the hot port so with the pump running you tweak this down tighter and tighter and tighter until very little water is going back to this tank it makes sense Bob you know all right now let's say that mixing valve has tight closed off in other words we have a master mixing valve here that does not have any leakage coming into the hot port right here you don't need the bypass balancing valves why all this research water that's coming back none of it can go into the tank because none of it can come out of the tank so in that case the reason return water is coming back here going back into the cold line and then out here where the heat is transferred out to the ambient conditions and then back so creep is eliminated when you have a valve that can close off tight let's talk about balancing very very important balancing is is you know cannot be underestimated here what we have is some pictures of different types of balancing valves this is a manual balancing valve from Coletti this is a variable orifice type here is a fixed orifice type of balancing valve manual and here is a caliph a quick setter which is a very unique manual balancing valve that has a built in flow meter this product right here is a dynamic or an automatic balancing valve it has a fixed GPM cartridge in here so when you install that it will maintain a fixed GPM value even if if your pressures fluctuate and this is a thermal balancing valve right here the Collette one sixteen series so any of these balancing valves can be used successfully with either an electronic master mixing valve or a thermostatic master mixing valve so let's talk about balancing a little bit here's a circuit that is not balanced so you can see coming from the water heater the riser that's the closest to the heater is going to get the most flow the next one will get a little bit less and then the one way out at the end is going to get very little flow if any because we don't have any balancing going on in this circuit it's a big problem especially if you're someone out here at the end of the line trying to get hot water what if you put in a manual or an automatic balancing valve what you do is you set the GPM for each of these risers to be the same so a manual balancing valve or an automatic one will set the same flow rate now we're balanced okay what I want to talk about is a thermal balancing valve it's a different animal okay it does not balance GPM it's shown right here this kalevi thermal balancing valve the thermo setter uses temperature so rather than looking at GPM numbers we're looking at temperature numbers so all you do is you set this dial to a specific temperature and they modulate open and closed to vary the flow in each of the risers to maintain temperature so it's it's a really interesting concept so I want to spend just a little bit of time talking about that here's a cutaway of the kalevi 116 so this gold-colored element right here it's the same kind of thing that you would see in a master mixing valve that's thermostatic so it's a sealed wax element expands and contracts and as it expands it contracts it opens and closes this seat right here it's the only balancing valve that actually modulates flow in a riser that's what's different about it here's a graphical representation of how it works let's say we had the dial right here tuned in at a hundred and forty degrees Fahrenheit as that water cools off let's say the hot water supply is depleted or you're doing a start-up or something like that if the water coming into the valve is lower than what you have set the valve will modulate open what does that do that brings more hot water to that riser to then bring the temperature up back up to set points so these valves will generally work right in this region right here they'll modulate open and modulate close to maintain temperature at that location so very very interesting concept it eliminates balancing altogether right if you install this valve and you set the setpoint knob there is no balancing you just walk away it will still do what it needs to do to control temperature at that point and I have a saying I like to use it's a temperature solution for a temperature problem so we're not having to use a differential pressure manometer and tweak and use charts or circular tools to set differential pressure that then corresponds to GPM that then corresponds to the temperature right because that's what you're doing with the manual valve and it doesn't rely on a fixed GPM it just goes right to the point and controls temperature what does that look like in a system this is a nice graph I like to use this here's some staged tankless water heaters let's say that during normal operation these are set for 140 degrees so they're delivering 140 degrees to the electronic master mixing valve we have that set at a hundred and thirty which is a good supply temperature and that supply water is going out to the system where we have anti scald valves okay very important at all locations to have anti scald valves if you are delivering water temperature anything north of 120 Fahrenheit so then also in this schematic we're showing the the 116 series balancing valve where you install those is on this return pipe just before it joins back to this main return pipe trunk here so this location is after all the fixtures when you're coming back on the on the way to the the variable-speed research why do we have a variable-speed recirc pump here think about that for a minute I mentioned that the 1/16 valves the thermal balancing valves modulate flow that's different right they're not the same as the manual or automatic so as these thermal valves open and close what's that doing it's changing the head loss in this return pipe so if you put in a variable speed or a smart pump here and set that for a constant differential pressure it works great with these thermal balancing valves because as they control temperature this pump will ramp up and ramp down to deliver the head pressure necessary to deliver the right temperature water out through the system so you could call that a great marriage ok we had another question that came in what if I set my tankless water heaters to the temperature that I need at my fixtures do I still need a master mixing valve technically no right so if we if we wanted to deliver 120 degrees out here we could set these water heaters to you know whatever 125 and eventually just deliver that temperature directly out here a couple of things to keep in mind if you do that one is your return temperature by the time it comes back in your research lines and gets back to your research pump that water may be tepid it may be at a hundred or ninety five degrees that can be a problem and I'm going to show you why on the next slide so you're operating a low temperature system that can be susceptible to bacteria another reason you may or may not want to do that is if you set these to 120 that's all you have so if you have any kind of industrial washing machine or dishwasher or if you have anything out there that you know wants to use really hot water then you don't have the ability to do that so great question thanks for that question I took about elevated temperatures I want to just touch on controlling Legionella bacteria using elevated temperatures or what we call thermal disinfection okay I have a whole another presentation on this so we're not going to go into too much detail but just briefly Legionella bacteria like shown in this picture here is everywhere it's in lakes and streams and and even in the dirt now it can actually get through the municipal water treatment as well so it's very very common or can easily get into your plumbing system okay so this stuff getting into your plumbing system will find a place if the water is right here in this optimal growth area between you know in this gold band here between zip like 68 and 118 or whatever that is that bacteria if it can hide in the biofilm or the scale or any corrosion layers it will grow and proliferate in your plumbing system so keep in mind this temperature range right here so to kill that bacteria there are two things you need to consider first of all you've got to get up into this kill range you've got to get up above this point right here into the red zone or the kill zone and you have to maintain that temperature for a period of time so it's a time and temperature formula to kill Legionella bacteria so why do I talk about all this if we have a thermostatic mixing valve okay you can sit that on the tank and set it set your tank temperature for 140 using your aqua your aqua stat or whatever is controlling your storage and so this water is safe right this water is 140 so it's up in this red zone you won't get any bacterial growth in this in this condition but what happens when you deliver that water through the thermostatic mixing valve out into the system and back it's it's very possible then your temperatures are going to be down into this range here which is undesirable you want to stay out of that range all the time so a thermostatic mixing valve protect the recirculation system because you can't elevate that temperature up above where you need to be to deliver the temperature water that is going to kill the bacteria now with an electronic valve you can do this you can actually disinfect the whole recirculation system either by manual or an automated process so most of the master mixing valves out there the electronic ones on the market have a button on the front or somewhere in the user interface that you can activate a shock and what that shock will do is it'll tell the controller to set the tempered water setpoint up to 160 or so and what you want to do is leave it up there for about a half hour I know this says kills bacteria instantly but you need to recirculate the whole system for like 30 minutes or so at those temperatures and you need to monitor that return temperature so the Coletti legion mix product has that returned sensor that we looked at earlier it will look at that return temperature sensor and make sure that we're well up in this kill area for that half hour to make sure that the whole system gets gets sanitized an electronic master mixing valve can interface with the hot water source so maybe a contact output for example can tell the water heater to go to a higher temperature if you have a second aqua stat for example and an output on the electronic control can make sure that the research pump is on so whenever you go into this mode and you're doing a thermal disinfection of course your research pump has to be running so you can verify that that's on and if your controller has memory it can log everything that's going on so the the Coletti product has a 40-day first-in first-out buffer that records everything all the time so it will record all the temperatures the supply and the return any alarms that occur any status changes and gives gives the the building owner of the building manager a complete history of what's going on those are important things to look for if you're going to employ this this strategy so how does that look now back to our system picture so what we would do during this thermal disinfection is jack up our supply temperature to about 170 mix it down to about 160 send that very very hot water out through the whole system come back at 150 now we are well within that kill zone for that half hour period or whatever you set it to to make sure that all the bacteria is killed and it will even kill the stuff that's hiding in the biofilm and the corrosion layer because if we're at 150 degrees for a half hour that whole pipe is going to get hot so this is a very effective way to control Legionella is with is by using elevated temperatures and you need that electronic master mixing valve to do that so I talked about that thermal balancing valve and then elevated temperatures well if your thermal balancing valve is sitting there at minimum position how do you get enough water flow through the system to do that disinfection the thermal setter has an optional second cartridge here so this is another thermal element if you send 155 degree water down the pipe this element will pop open and that's represented by this green curve right here this is the bypass disinfection cycle using using the second thermal motor it has a real tight throttling range so what it'll do as soon as it sees that temperature from 155 to 160 it opens up to a CV of 1.2 now that's a nice big CV so if all the balancing valves are opening up then that will allow you to get really good flow through the research system and allow you to accomplish that disinfection cycle there's another option too and essentially in that second part of the body is a little zone valve and it's actuated by a 24 volt spring return on/off actuator 2 wires so you can send 24 volts to all of your balancing valves and pop them open any time you want to to do a you know to open up the valve to a CV of 1.2 so you can get a good flow through the system when you're doing a flush or a disinfection cycle so I wanted to mention those as kind of an added advantage to that thermal balancing valve if you if you're going to do thermal disinfection how we doing there Bob mark any questions so far yeah there's been quite a few coming out of marks and typing back responses I haven't seen but that will grab some at the end oh great well we're doing good on time so there will be questions at the end only have a few more slides and we'll have time for questions so keep them coming alright so let's talk about service and maintenance you know comparing thermostatic to electronic valves we know that scale is a reality hard water is everywhere it's tough on everything it's tough on valves as tough on pipes just plan for it this is something that it's important so what you want to have as as a building manager and owner is to have a regular inspection plan it's a lot better if you install isolation valves I know that's an initial cost but we don't always see that so that causes really headaches during service and maintenance you know that scale removers like the slime away stuff and CLR and vinegar and water I know Bob is a big advocate of this you can actually pull a valve out you know drop it in a bucket of this solution and brush it off and rinse it off and put it back in service so that's something to know at least our valves are cleaned that way now look for a valve that has internals that are designed to resist this okay if you have I know I know the coal efi mix cal valve the engineered polymers inside of there really resist scale buildup and it's easily flushed away because it's really smooth look for a valve body with Union connections anyone who's done any pipe fitting or plumbing will know that Union connections are your friend Union connections just allow you to quickly pull a body out and clean it and put it back in and minimizes downtime so that's that's a nice feature something to think about - electronic assemblies that have the integrated controller so if you have a master mixing valve and the controller and the user interface is attached directly to the valve those can be expensive and difficult to service and you might have to take them offline completely so that's something to consider one good thing about electronic valves is they can let the service people know what's going on that can generate a service alarm if you have a sensor fault or a high temperature alarm of course you can't get any of that with a thermostatic mixing valve so that's a really big advantage for electronic valves you know in the realm of service and maintenance and something I didn't mention yet but our valve and I know I think one other product on the market has something that is a full cycle exercise so it's an automatic maybe in the middle of the night where the valve goes fully open fully closed back to fully open and what that does is it actually exercises the the movement of the valve and seat and it can clear debris and reduce service frequency because you're flushing away anything that might be you know trying to cling to the the seat and the plug or the ball of the valve so that's a great feature to have that's it's helps with service and maintenance few other items to kind of sum it up and take away I mentioned early on that thermostatic valves tend to be lower cost okay we know that they're easy to install there's no wiring no electricians so that's why they're so popular they've been around forever and there's nothing wrong with thermostatic mixing valves if they work for you electronic systems with a full function user interface what I'm talking about here is the the push buttons for configuration and the display and the alarms are everything are right there on the wall mounted at the user interface compared to a master mixing valve that you have to bring your laptop out there and plug in the laptop and then bring up your your browser or your application it's just really nice to have everything right there in the user interface that you can you can go to our product the collect eligio mix actually has 11 languages in it so you can select you know everything from French to Spanish to - you know it's a global product so if you are working with customers in a global way or if you're working up in for example Montreal or down in a state where maybe the building manager would prefer Spanish you can just set that really a great feature a couple of other technical things the seals in the collectively geo mix are made of peroxide cured EPDM and that's important because EPDM when it's peroxide cured then stands up to chloramines and a lot of public water has chloramines in it a PDM that's not peroxide cured will degrade quite rapidly compared to the peroxide cured seals and if you are using a brass product you know a lot of valves out there or either they're stainless or bronze or brass if you buy a brass master mixing valve it's better to get the DZ r or d zinc in vacation resistant alloy and that stands up to aggressive water because aggressive water can actually leach the zinc out of the brass and it causes micro cracks and eventually the brass can actually fail if too much of that zinc is is extracted out of the brass so just kind of sum it up here as you can tell we believe that an electronic master mixing valve coupled with a variable speed or a smart recirc pump set that pump to constant differential pressure and put in a thermostatic balancing valve and that will give you the ultimate in in a modern you know for a modern domestic hot water control system so that's where all this was leading a lot of advantages to electronic master mixing valves wanted to show you this picture this is a great shot of a retrofit project and the first thing that kind of jumps out at you here is how small that Li geo mix valve is compared to where there was a large thermostatic mixing valve assembly the the second thing is there are some balancing valves there you'll see three of those remember we talked about thermostatic valve having some flow through on the hot port and we needed those little balancing valves in there to prevent creep this contractor that did the retrofit he just left them in there they're not required for use with this valve you just left them in there because it's easier to pipe so it's a great picture for those two reasons and it shows some really nice work so um let's see yeah so those valves were left full open they're not not functional they don't do anything the Coletti product there has a little integral temperature gauge so you can see the mixed sensor right behind the gauge we've had some comments and questions coming in concerning applications of thermostatic mixing valves and the questions were along the lines that does the does the CLEF a thermostatic mixing about is a problem if they go through periods of no use in terms of functioning properly and and one of the writers had indicated that they see and and like college dormitories were saying it there's no demand for the summer that afterwards the mixing valve a mixing about not necessarily kalevi wasn't working correctly and this photographs is a good point to make about thermostatic mixing valves thermostatic mixing valves in in if you have any type of hard water situation even two three grains they naturally wipe any calcium buildup as they as they exercise as they modulate as there's demand they basically go up and down up and down but with really really hard water that can end up becoming you know the problem in most thermostatic mixing valves in hard water applications will actually that's the failure mode think it's and but it's especially pronounced in cases where you have a little bit of hard water but periods of no demand and because they're not exercising they're not moving and maybe the hot water heater is still left on in that dormitory say for other purposes and if the mixing valve is in close proximity to the hot water heater even though the temperature of the water isn't the highest at the mixing valve there will be some calcium that comes out of solution so three months goes by there's a little bit of calcium buildup on that on that shuttle mechanism that you showed Kevin and so when there's demand it's locked in that position and you're going to have to cool of water and it's just not going to be stable or maybe to warmer water and so that's for digital mixing valves if you have hard water conditions that aren't solved by other means such as water softening and the like is a really good solution and this particular example is a case where a thermostatic mixing valve had hard water scaling problems and was replaced with a valve that actually exercises and is digital so that was a really good really good point a good question that one of the listeners had there's another question you see we got the our but as it relates to a SSE 10:17 the question Kevin you showed a slide that talked about the the the the maximum temperature variation that a valve needs to stay within based on flow rate three five seven degrees do you know is that is that is that a test where the outlet temperature is measured and then the water temperature and in that now that is changed and variation is measured or is the outlet temperature that you are the setting of the valve say 120 degrees you set it 220 degrees is a test that you're just measuring that the outlet temperature is within plus or minus 3 degrees of that it's not a time-based test it's basically accuracy based test there is a period of time they say you know change the flow reduce it by 50% for example and wait I don't remember what it is maybe one minute two minutes and then take the measurement so there there are some periods of time in there where they actually take that measurement and let the valve steady out okay very good back to digital mixing valves you talked about different brands well some brands might have an exercising feature other brands of digital mixing valves perhaps not is there a time of the day that is recommended for exercising and if so when is that is the question just in the middle of the night some time when there's generally little to no use that's the best time to let the valve go through a stroke the légion mix valve takes takes a couple of minutes because it's a 60 degree stroke so it goes all the way one way all the way back and then back to where it was so you don't really want to do that when you have high usage okay very good another question came in concerning when you're showing balancing commercial recirculation balancing valves in this case the question was do the thermal balance does clef ease thermal balancing balance close off a hundred percent oh the balancing valves no they they have a minimum cv if you remember that graph there was a horizontal line near the bottom of the flow the 116 has a minimum if you have to have that or the the thermal motor won't know what to do you can never shut the water off completely so there's always a little bit of a flow through there so the valve can react to temperature changes another question came I gotta get another scale question are some products thermostatic mixing bells more susceptible to scale than others I suppose that means brands and I'll answer that yes they are it depends on the material used inside of the thermostatic mixing belt because all things being equal scale will precipitate out on surfaces in different at different rates polymers as an example are more resistant to scale accumulations in metals so a valve that has a generous use of polymers versus metallic type moving mechanism inside of their valve will be more resistant to scale accumulation and Nicoletti mixing valve has the shuttle mechanism is a polymer type design mark if I could add the two it's the temperature the hot water has a big effect on how often the male scales up too because we know that you know the minerals precipitate precipitate out at the higher temperature so if you're feeding the mixing valve 170 degrees on the hot port there's a potential to get a lot more scaling on it from seeing like a hundred and forty degrees or one hundred and fifty degrees and there's a I forget what the factor is I think it doubles forever ten degrees or something like that the scale precipitation so usually when I see a valve that scales up quickly like this this question here within the first 90 days they said they were seeing issues it could be that the hot water number one you've had hard water extremely hard water possibly but also that they're running that tank and that will they to temperature to another question that probably Bob your best to answer this is related to that if you do have a problem with the thermostatic mixing valve with scale is it recommended to just replace it or can you clean it or it depends well yeah and this picture is a good a good place to be and I can explain what I've done in a couple jobs especially a job like this where it's a critical application if you put three ball valves on all three sides of that and a little service port and exit like a web stone valve for example of some of your folks another web stone it's got a ball valve shut off and it's got a little full port bow belt next to it you could actually run a cleaner through that valve without taking it out of there you could just you know take the pressure off it shut up all those three valves and hook up your D line work it like you use for a tankless water heater and usually it only takes about a half hour running that D lime or acid through there that you can clean them out if they're not plugged up completely we're hunters not going through and then obviously probably gonna have to take it out and replace it and take it back to the shop and give it a good working over but if you're going to do a yearly maintenance on it you had those three isolation valves on that just like you were doing a hydronic system isolate a component you could just get one of those little five-gallon bucket kits and comes with the cleaner and everything and just you know deal I'm that Valve right in place so that's another option for you know I'm going maintenance where you do have hard water conditions okay very good another question came in and it might have been shared with the audience already but as it was relating to the growth of bacteria which is as we know becoming more and more commonly communicated in the in the press and the media the question is does Legionella grow in water or on the pipes for example if the research water is always taken back to the heater and heat it back up to 140 would that sufficiently address bacterial concerns like I mentioned earlier it will look for somewhere to hide and feed it has to it has to feed off of something so it's going to look for a place where it can stick stick to the wall of the pipe where there's some biofilm or corrosion or somewhere where it can hide now if it goes back to the heater yeah it'll it'll be killed as long as it stays in the 140 degree water for a half hour but generally it will proliferate in the layers of the piping for letting us be with you for this last hour and see you later yeah thanks everybody and thanks to my team at Coletti for putting it together thanks Mary see you on the next one bye bye

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