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SUNMAXX SOLAR HOT WATER SOLUTIONS
TROUBLESHOOTING AND MAINTENANCE II
Date: 11/01/2010
Okay, well I’d like to welcome you to the SunMaxx Series Solar Hot Water Webinar: Maintenance and Troubleshooting. I’d like to spend the next half an hour speaking with you about different maintenance and troubleshooting techniques that we find very successful. As always, I’d like to remind you to type a question in the chat box. Since we have a relatively small group, this might lend itself well to discussion-based webinar. Without further ado, I’d like to get right into our first slide. And I see, can somebody confirm I’ve got a little graffiti it appears on my screen, is this the case with everyone’s? Some stars, some scribbles, and a few good mornings, or is the screen clear?
Okay, now one of the most important things in terms of troubleshooting and maintenance – sorry Jess, I’m not sure who or what was responsible for this. Oh it’s no problem Tim, we’ll just have to see right through it. We’ll see if I can. Well, a little technical glitch I’ll work out later on. In order to properly troubleshoot and maintain a system, system commissioning is most important. In proper system commissioning you can avoid many of the problems associated with solar thermal systems. A lot of times they do fail because of installation errors or they fail due to neglect. So I’d like to go over four basic considerations that should be made in proper system commissioning. I also want to remind you that you download this pdf form of the webinar, and here you have a link to our brochures resource center through SunMaxx website. So when I say refer to the technical manual and other SunMaxx resources, you should be able to simply click on that and it takes you to our information center, or you can visit sunmaxxsolar.com and go right to the information center where you can download our technical manual. In the technical manual, you will find a troubleshooting and maintenance system commissioning guide.
So the four things that I want to specify regarding system commissioning are pressurizing the closed loop, purging the air, getting the air out of the system is probably one of the most important steps in making sure that early on your system is operating properly. And over the course of the first couple of weeks you may have some pump trouble if your air is not completely purged. Another one that we get a lot of technical calls on is programming the controller and then, obviously, mixing the glycol. So one of the first things in terms of pressurizing the closed loop is that you’ve got to use a pump that’s capable of building up enough pressure to ensure that there are no leaks in the system, and our SunMaxx filling station can do that. There are other ways, you can buy at least a half horsepower sump pump from one of Home Depot or Lowe’s. And you can do it this way. Our pump’s filling station not only has the appropriate size pump to build up to roughly, depending on the vertical height, it can build up to 50 or 60 psi, but that also has a filter, and the filter with the aperture allows you to clean all the debris out of the loop.
So, what we like to recommend is that you first pressurize your system with air. Using a modified trader valve, you can build the pressure in your system up prior to purging and flooding your system. Pressurize it with air and you can pressurize it up to 75 or 85 psi. And be sure that it holds the pressure for several hours; so this might be something where you do it at the end of the day and you pressurize it, mark your pressure, and come back the following day. This’ll be a first step in making sure that your system is nice and tight with no leaks and no places for air or water to escape. Another thing that you have to do before you pressurize and commission your system is determine what your system pressure will be. What would you like system to operate at? Now, we recommend that you choose a pressure that is most appropriate to the vertical height. And simple calculation would take the vertical height, divide that by 2.31, and then add 1 atmosphere to that. That would give you what your target pressure should be. I do want to point out that pressure in a system does not affect system performance. So, if you end up with your system charging pump being capable of 20 psi, but you estimate that you should have 30 psi, you can rest assured that 20 psi will offer no difference whatsoever in system performance. So, you want to make sure that your at least higher than 1 atmosphere and not to exceed 90 psi. The relief valves on our pump stations are set at 87 psi. So you want between 70 and 90; it’s going to give you the same system performance. It’s really a question of liability. How much pressure do you want in your system continually? Often, the lower the pressure, the less liability.
Now, one reason why determining your system pressure ahead of time is important, that target pressure, is so that we can properly assess what size expansion tank you should use. So, for example, if we determine that your system pressure should be at 35 or 40 psi, that number is what we’re going to use to help establish the size of your expansion tank. And should you realize that your pump is only capable of bringing your system up to 20 psi, that in itself is not a problem. The problem lies in the fact that the smaller or the lower the pressure, the larger the expansion tank will need to be. So, knowing your target pressure and shooting for that target pressure is important. But ultimately, determining what your pressure is ahead of time allows us to accurately size the expansion tank.
Now once we’ve determined this and we’ve commissioned the system or purged it, we have to get all of the air out of the system. There are some built-in mechanisms. The air purger in the pump station is a manual air purger. There’s the built-in air scoop that will build a pocket of air bubbles. Then we recommend that you shut this air purger down with a ball valve. You can see a ball valve on that nipple coming off of the supply. That air purger outside should really only be used during system startup. This is not necessary. However, with drainback systems, as you will be maintaining a bubble of air in a drainback system and you don’t want to remove all the air. In fact, it would be impossible to remove all of the air with a drainback. So, purging systems may take several days. For those of you who are doing a job an hour or two hours away, several days of purging air is not really something you want to look forward to. However, it is essential, because if you purge the system, you commission the system, and you think you’ve got all the air out, as temperatures increase, the ability to store dissolved oxygen decreases. And it may seem like you have all of the air out. In just a couple of days, there will be another pocket. So please remember that in the SunMaxx pump station, there is a automatic air scoop. And this air scoops will build up a pocket of air.
It will take all of the air out the loop. And it will prevent it from cavitating the pump, but that air still will be trapped inside of the pump station and will need to be manually bled, and we recommend that you do this once a day for the first week. This may be something that if you have a long distance installation you can train your homeowner to do this. What this will do, by getting rid of all of the air, is increase the likelihood of total system success. So purging air is extremely important. Now, in terms of programming the controller, if you use a SunMaxx IntelliMaxx controller, regardless of the model, all you have to do is plug that controller in and bring 120 volts to the controller. Automatically the default settings will allow that controller to operate your system. There are delta T on and delta T off settings preprogrammed, and they will work, however, for climates such as the one that I’m currently in in the Northeast and even in the Northwest, we recommend that you adjust the delta TO so that your pump 1 turns on at a differential of 15 degrees. In the middle of winter, we often recommend that that delta TO is turned up to even in the neighborhood of 21 degrees. This will decrease the pump turn-on, turn-off cycles. The max temp should turn the pump off when it reaches 175. There is a default setting programmed for the maximum temperature, however, you need to activate that setting.
So, the default settings on your controller will simply turn the pump on and turn the pump off based on the differential. But there are many other parameters that you can allow your controller to do as long as you activate that particular setting. And the max temperature setting is one that needs to be activated. Your second array, usually tied into a recirculation pump or a three-way valve, can also be adjusted. If you choose the array, for example with the IntelliMaxx DHW plus, there are several arrays you can choose from. You have to find the array that best suits what it is you are trying to accomplish. And just visually, looking at the location of the pumps and the location of the exchangers, and then go to that section in the manual. It will describe exactly what you need to do for array number 2 in order to activate all of the functionality and to adjust the delta T. So once this is done, you should have virtually a maintenance free system. And if you have any trouble programming your controller for the exact option you are trying to activate, as always you call the 1-877-SunMaxx and dial into the extension for technical support. There are several, one of them is extension 229, we can help you program your controller when you get to that point.
Okay, so like I mentioned, each controller comes with several different arrays. In our CombiPlus controller there are 11 or 12 different arrays. Now, one thing you can do if you do not find the array that most suits what you are trying to do, we can use these arrays and modify them slightly. So if we know that, for example, array number 1 has pump number 1 and has recirc pump number 2, well that recirc pump number 2 is visually depicted as being a recirculation loop that is bringing heat from the first tank and dumping it into the second tank. What we can do is, if you prefer to have a valve in place of that second pump we can help adjust those delta T or thermostatic set-point. I’d like to also point out, one nice feature to these controllers is they allow for both thermostatic control and differential control. That is, they will send voltage from a relay, for example pump number 1, the standard is that it is based on the differential between sensor 1 and sensor 2, however, given the right array, you can activate a pump not based on the differential but based on the exact set-point. So if I know if I want to replace, in this diagram, pump number two with a valve, I can program the controller to make sure that that valve opens, if it’s a normal closed valve, it will open at a very specific set point temperature. So that’s a thermostatic option. So each of these relays for all of the arrays has what’s called a thermostatic option. And that is, it will activate and energize based on a specific set point rather than a differential. Should you buy your glycol from SunMaxx, you will find that it is premixed. It is premixed at 50% concentration. What this means is all you have to know is the total volume that your system’s going to hold. You do not have to mix your glycol. However, it’s extremely important. And I know many of you will try to shop around and find value in the different components, which is perfectly fine. But I would caution you that different manufacturers sell different concentrations, if they are already premixed at all. So be sure that you know exactly what the concentration is before you begin to do your mix. Along that same line, when you do your mixing, you must be sure that you have accurate volume for your whole system.
And so what we recommend is that you fill your entire system and then you drain your entire system. What this will do is accomplish two things. One is that, first, it identifies exactly what volume of fluid you have in your system, so we know how much glycol to use, how much water. But secondly, it essentially filters your system out by cleaning out the pipes. It removes any shavings or debris that might be left inside the pipes that would normally get caught in the pump or valves, slowly degrading the system. So filling your system and then flooding it and purging it will first allow you to identify exactly what volume you have but also it will help clean your system out.
Now, in terms of system maintenance and yearly maintenance, one of the most important things you can do for a closed-loop system is be sure that the pH never falls below 7. Yeah, Don, I think that by filling your system with plain tap water, it’s most cost effective. You don’t have to do any trial and error with your glycol, but if you measure what leaves your system or what you put into the system, that gives you an exact number to go with in terms of system volume. And then you can just flush that water right back out and down the drain. So, in terms of maintenance, one of the very tricky things is to be sure is that the pH never falls below 7. And with glycol, there can be some indication that you’re losing acidity and a very slight drop in pH. But it could happen overnight, after the course of two hours and your system stagnates, if there are collectors, if there’s glycol that is still in your collector, that it will turn acidic. And what could happen to the pH is that it will literally drop off logarithmically. It won’t just go from 8.3 to 8.2 to 8.1. It could drop from 8.2 down to 7 and then down to 6.5. So you have to very close attention to the pH and also the system concentration.
One big mistake I’d like to point out is that a lot of boiler and HVAC guys who install cold water makeup valves to their heating loops, which is standard. However, when installing a solar thermal loop, the last thing we want in that line is a cold water makeup valve. And I have seen a couple of cases where a cold water makeup valve line has been installed with a leak. So there’s a small leak in the glycol bay system, which introduces 100% water back in, reducing the concentration of the glycol, causing it to freeze. So make sure you have the proper concentration and that your system pressure is maintaining +/- 5 psi year round. Also measuring performance is something that a lot of guys will overlook. There’s some very simple ways to measure performance, all of which are laid out in our technical manual, and I’m going to go over it in just a moment. But being sure that you’re setting up a baseline performance data, so for the first week or the first month or the first year, it’s important that you and/or your client have a very good handle on how well the system’s performing and what can I expect out of it. And should you see a decrease in performance from one year to the next. Then you should begin to look at what would cause such a decrease. But the bottom line is that you need to have a baseline, and system performance can be measured analytically or anecdotally. I’ll present to you a very simple way to do that in just a moment, and obviously the mechanical integrity.
Now making sure the pH is accurate, you can use one of many different tools: a digital pH meter or a little pool kit or you can use a pH testing probe for example. These can be purchased from different companies. The easiest which would be to purchase a pH kit from a pool company. And with simple litmus paper, this would be a good indicator. Obviously, if you’re going to get into the business and become more professional at solar thermal, you’re going to want to get a nice digital pH tester. What can cause pH to go down is consistent and excessive temperatures that exceed the manufacturer’s recommendation of the glycol. So as a manufacturer ourselves, we have two grades of glycol. We have what we call the low temp glycol which is rated for about 250 degrees Fahrenheit, at which temperature it begins to break down and turn acidic. We also have a high grade, high temperature glycol, which is rated for somewhere in the neighborhood of 360 degrees. So, personally I highly recommend investing a little bit more money in a high temperature glycol, that way you can be sure that even in the worse case scenario, during system stagnation and you do overheat your glycol, the buffers in that glycol do not break down and do not cause the pH to become acidic.
Now measuring concentration can also be done with some very simple tools. Many of you look at the concentration of your anti-freeze in your car radiator from a tool that you buy at NAPA. That same tool will suffice, a simple hydrometer will allow you to maintain the concentration. Perhaps it is something you can include as part of your maintenance and service contract with the homeowner. You buy a pH test kit and you buy them a hydrometer and say this is included, this is something that I would like you to look at each year, and if we have any indication that concentration is dropping or pH is dropping then you can make the drive out to his house. Perhaps that’s something they can do. Either way, whether you do it or they do it, you’ve got to be sure that at least once a year of the proper concentration of your glycols, especially going into the winter, it would be something you would do as a normal boiler service call from a fuel company each fall, they would come out and check the boiler. You should do the same with a solar thermal. Coming into the winter, the most important thing you can check is the concentration of glycol. Now, you really have to shoot for a concentration between 35 and 55%, depending on your location. The further north, the closer you would need to be to 50%. But one thing that many people don’t realize is that as you exceed 55% and into 60-65% glycol, that’s going to change the solution or the makeup of that solution and cause the water to separate from the glycol.
We don’t want the water to separate from the glycol because then the water will freeze on it’s own. So you want to have a nice solution and maintain that solution, and a good solution is mixed to maintain between 35 and 55%. So, I’ve heard people throw around the idea that ‘oh I’m just going to use 70% or 80% glycol.’ That would lower the freeze protection, but it would also encourage the separation of glycol and the water. So, more is not better in terms of concentration of your glycol. Now maintaining your pressure, most pressure gauges have a little red dial that can be moved and set as your target pressure, well this needs to be marked during system commissioning so that you’ve identified what your starting with and you can easily correlate any fluctuations from this standard. We’ll also to identify your target pressure, so before you even commission your system, use the little red dial and set it at whatever pressure you’re trying to achieve, get your system up to that pressure, close it off and come back the next day and be sure that you haven’t lost any pressure. And then fill your system up and put the tubes in or get your pump running and you should be fine. Make sure that that mark stays in place, and you can even use a permanent red marker to help you be sure.
That’s a great question, how do you extract any glycol without introducing air back into the system? What it really just takes is a very, very small amount. You should have a small drain cock in your filling station as well as any drain of your pump station is going to let you drain just a little bit out. You really just need a few drops, so by removing some of this glycol you will drop pressure but it’s going to be a very, very, very, very small amount, minute amounts. So what you want to do is use the fill ports, the fill drain port on your pump station to extract several milliliters of glycol, no more than that. And by removing just that small amount you shouldn’t have any problems with getting air back into the system. But, if you do have air back in the system, the pump has a manual air bleeder and so in a very short period, in a matter of just a few minutes, you should be able to get that air right back out if you did get some in.
Okay, now measuring performance. This text that you see here on the slide is all laid out in the technical manual, and you can find a section in the technical manual of measuring performance. Basically what you want to do is look at the amount of energy that is brought into the solar thermal storage tank on any given day. By looking at the amount of energy or temperature gain of a fixed volume of fluid, that can correlate directly to the number of BTUs because we know it takes 8.3 BTUs to raise one gallon of water one degree Fahrenheit. So if I know for a fact that I have an 80 gallon storage tank, I’d look at that 80 gallons and multiply that by the number of degrees rise throughout one day and then multiply again by 8.3 and that should be equal to the total number of BTUs that my system was able to produce and deliver to my storage tank on any given day. I want to choose a day that I don’t have a load. It becomes a little bit more difficult to calculate production and subtract load in looking at the storage tank. So try to find a day when there is no load and every BTU that we produce goes into the storage tank, and that number is a direct result of gallons times 8.3 times rise in temperature. That’s going to equal your BT production. And from that number then you can look at the SRCC report and see what they would expect you to produce, you can look at the TSol that you should have gotten with a quote or you can call your sales rep or call myself, for example, and say ‘I’ve got a 40 square foot system up in Seattle, Washington and I produced 4-7,000 BTUs today, is that appropriate?’ and we’ll be able to tell you pretty quickly whether we think you’re right in line or not, but it’s important to have that done and have that in place so that you know exactly what your system is producing. It’s also important for the homeowner, to educate them how they can measure their performance because, from experience, homeowners really like to know how their system is doing and will go out of their way to make their own calculations and perhaps keep a log, and that log can be invaluable for troubleshooting. So it’s important that you do educate your homeowner.
Now making sure that all the mechanicals are intact, a couple key things that you sure of that the bolts are secure and the fasteners are secure, there’s no leaks or tears. With flat plates you want to be sure that the underside of it is cleaned of any debris, there’s no leaves, no buildup, no squirrel nests. With tubes, you want to make sure the caps on the bottom of the tubes are snug, preventing them from falling down out of the manifold, and that your controller wiring is tightly sealed, there’s no penetration into your wiring because that’s going to increase the resistance and change your readings slightly.
Now moving forward, this troubleshooting maintenance table again has been taken right out of our technical manual, so this is a very good first step line of defense, so to speak, so that if you have any trouble you can work through this and if this doesn’t help you then call the SunMaxx tech support line, and that’s where we can step in and be of good value. So, I’m not going to go through this troubleshooting chart, just to point out that you do have this available to you through sunmaxxsolar.com. Different situations where the pump won’t run, or the pump runs continuously, or there’s no circulation in the system, or you’ve experienced a large pressure drop. These are all the different causes of those effects, and some recommended actions that you might take to prevent that from happening in the future. You might be experiencing overheating, or based on your baseline data you’re seeing some performance loss over the first month or the first year or first two years. And if that is the case, and you do have good baseline data then you can start to look at what would cause performance losses.
Okay, as promised I kept it to 30 minutes, and I would like to thank you all for your attention. I encourage you to continue to visit us every Monday at noon. We would like to encourage you to take your time, do the systems as per our recommendations. Let me go back real quick, Don’s got a question. I’m going to stop the recording now for those of you who are going to archive, and if you’ll hang on Don I’ll answer your question momentarily. So thanks again, take care.
