Radiant heat disaster
Greeting folks,
I am in severe need of some help. My wife and I are currently renovating a home with in-floor radiant heat. I am attempting to put the system back into working order. Unfortunately, I cannot sort how the previous owner had this hooked up. I have been able to reconnect the in-ground lines into the manifold with minor issues so far. The most challenging portion is sorting how he had the outside boiler connected. The two red and two white 1in pex running through the wall and held in place by the spray foam run outside to a concrete pad where they end. The boiler that had been there was removed years ago and it is unclear if he had a pump at the boiler.
Any help or insight anyone could offer would be greatly appreciated.
Note: the white PVC is for potable water and not connected to the system at all.
Comments
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The fact that it has been decommissioned would make me suspect that it wasn't working when it was taken out of service.
There are so many stories of people who just build heated floors without designing them. They figure it's gotta work. Actually, it doesn't. There's a good chance that with a system like this even if you get it back working as designed, it's not going to work that well.
I don't see any zone valves, which makes me wonder how it was controlled.
Even though you've hooked it up, I would start by blowing compressed air through each loop to make sure it's not obstructed, and to make sure you have the loops matched up properly. I would want to know the length of each loop and where it goes. If they're not labeled I don't know how you figure out where they go. You could figure out the length of each loop by pumping water in with a pump and measuring how much water it takes to fill it.
Once you figure out what you've got under the concrete, we can talk about how to figure out how much heating you need and how to configure it.
What kind of heat are you considering? The fact that the old boiler was outdoors makes me think it was wood or something weird like that. That's another warning sign.
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We were told that the system did work previously but the system was drained when the previous owner moved about 30 minutes away and did not want to return on a daily basis to fill the coal/wood boiler (and the fact that the neighbors constantly complained about the coal smoke). The building sat empty for several years and was used as cold storage. From what i can tell the zones are controlled by thermostats which run pumps through relays, the three black boxes on the wall.
Fortunately, some of the lines are labeled as to the zone they run to/return from but does not include length. Ill work on blowing compressed air through the lines. When we are able to run water through the lines we are going to attempt to map the lines and label them by using a thermal imaging camera.
At this point I have purchased a wood boiler that will be delivered next week. I am starting to fear that i jumped the gun on that a bit.
Thank you again for your time.
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you might build a test gauge to fit onto that Pex and test one loop at a time, 60 psi will show a leak quickly. A test gauge on one end, shark grip cap on the other.
Or get a gauge like this with a female hose adapter. Screw it onto the drain valves on the end of the manifold and isolate the loops to test one at a time. That will be quicker than taking every loop off the manifold.
Any idea where the loops run to?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Looks pretty normal.
Circulate water though the exterior red pipes (so your wood boiler needs its own pump) and run the pumps to heat. You wire your thermostats to the black pump relays, these also have 24V supply if your thermostat needs it.
The plate HX can also be used to heat your hot water, depending on which direction your flow your boiler water, it can be priority over floor heat. No controls, but shouldn't need any.
Once you get it plumbed up and running, check the temperature setting on the mixing valves since you don't know what they are set for.
The white pipes might have been for a dump zone for the wood boiler.
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Pressure testing the loops is an excellent idea, basically you want to be as sure as you can be that it's going to work before investing time in it. My standard test kit is a pair of Sharkbite washing machine hookups:
Put one on each end of the PEX. At one end put an RV blowout valve to connect to your compressor:
At the other end put a pressure gauge. If you want to let it sit for 24 hours you can close the valves on the Sharkbite fitting.
The reason I ask about controls is it looks like all of the zones are on the same manifolds with nothing between the manifolds and the loops. So all of the zones are on or off together. What is the heated space like? Is it all one big room or a lot of little ones?
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Honestly, just start over. Leave the pumps, heat exchanger, and mixing valves (and maybe the copper and manifolds if you don't care about looks or functionality) but throw everything else away and start fresh. Wood boilers are almost always piped wrong and this is no exception. The underground lines (assuming they are the same non barrier tubing in the picture) are filled with groundwater now and will give off more BTU to the earth than the building. Dig them up and bury a single set of good foamed lines such as Thermopex, Rhinoflex, Insulpex, or Logstor. Nothing else is worth burying. You're going to need to flush everything to get the atmospheric crud from the previous boiler out of the lines, and to do this properly you'll need an additional heat exchanger (unless you don't want domestic hot water, which is the function that this one was previously serving, then you could reuse it for the radiant) and pressurize the whole radiant system with the appropriate closed loop components and piping.
The old wood boiler had a pump (or two) on it which circulated 24/7 through that heat exchanger on one loop and the white tubing on a second loop. Those two tees to the left of the heat exchanger allowed either of the two right zones to draw hot water from one through the mixing valve(s) and return cooler water back into the other as some sort of primary/secondary loop but it's very poorly executed. I do these wood boiler systems quite often and if this were my job, I'd throw away every component besides possibly the pumps and heat exchanger.
What make/model wood boiler did you order?
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So @GroundUp , just to clarify, you think the infloor loops need to be junked too?
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I think this is a bit of an over-reaction. Just because the original build used plastic and sharkbites, it doesn't mean it wont work. All the bits are there. Not pretty but will work.
I do agree about the underground insulated pipe, wrong insulation can get saturated with water over time making it ineffective. If your wood heat is cheap, not a big issue, you can look at it as free snowmelt.
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The loops behind the sink are labed as they go to the second floor of the residence. The other sections I assume go into the concrete for the garage and first floor of the residential section.
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I ordered a central boiler edge 760. From your feedback my assumption that the previous owner was intoxicated when he installed the system may have not been far off.
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Nothing overreactive about it. I never said anything about the plastic or shark bites, nor that it wouldn't work. I said it's piped wrong and should be started fresh to have a proper system.
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Meh, it's a lack of knowledge more than anything. I've seen hundreds of OWB systems installed by "professionals" that look worse than this. The biggest thing with OWB is that most owners are burning wood to save money, so they often end up hiring the cheapest plumber they can find or do it themselves with some guidance from their uncle Bob's dog's neighbor's brother in law and they end up with a clusterF like you have on your hands. The beauty of hydronics is that it's very versatile and even the crappiest of installs will still move heat from one place to another, but almost never are these OWB systems done correctly and yours is no exception. If you want it hacked together, it wouldn't be tough to make a few connections to what you have and make it work. If you want it done properly, starting over is your only option.
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I can only assume you're attempting to be facetious, but it's not working.
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Not facetious at all. Just not sure if when you say "throw everything else away" you're including that. Because I agree that the OP is probably better off assuming that nothing on that wall is going to be of use. But it seems that if the in-floor coils aren't leaking or crimped they're pretty hard to screw up.
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@DCContrarian it's painfully obvious that I didn't suggest he tear up his floors. Furthermore, I quite literally stated that the manifolds, etc could stay as-is if he doesn't care about aesthetics.
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Lets objectively look at what is wrong with the setup.
1.The two loops share the same takeoffs so they are not hydraulically de-coupled.
2.Open system, no isolation.
3.Questionable underground piping.
1.This is a non-issue if the pumps have an IFC.
2.Most of the bits there don't care about oxygen. The pumps will rust. Sample of one, but I have cast pump on well water and going for over a decade, so they might be replacement item every 5 or 10 years. Wood boilers are maintaince, so that is not a huge item. The cost of doing this properly (HX,pumps, feed, regulator, expansion tanks) is many times more than the cost of budget pumps. You can also replace pumps with brass/stainless when they fail.
3. If your fuel is cheap, replacing that is not worth the cost of digging plus pipes. Doubt that juice is worth the squeeze.
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Looks like it had a plate HX for separation? Or is that a DHW HX?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
That's for DHW
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have you pressure tested the system?
Ran water through to determine what line is supply and what one is return?
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Usual outdoor wood boilers are unpressurized. This eliminates any pressurized boiler testing requirements. It also introduces air into the system. This issue is mitigated by use of highly inhibiting corrosion inhibitor. No idea how good it is but this is what they use. Even with non-ferrous materials, corrosion is possible without corrosion inhibitor.
We did similar open systems for solar thermal but used non-toxic propylene glycol auto antifreeze. It has better inhibitors for this type of system. Never had any issues.
First step as mentioned before is to pressure test with air or water to see if everything is intact.
Are you considering another outside wood boiler? Not a big fan of them but they have their place, I guess.
Most outdoor boiler companies sell some sort of inhibitor.
If you are considering an indoor boiler like a wall hung gas unit, then either corrosion inhibitor or automotive non toxic antifreeze would minimize eventual corrosion issues.
Tom Gocze0 -
As a newbie DIYer, may I suggest that the Original Poster look for Caleffi's excellent iDronics Journals (here: https://idronics.caleffi.com/magazine-archive) There are other Manufacturers such as Taco that also provide educational materials. I shouldn't assume that jjustham is not a professional but if he is not, then all of the abbreviations and other jargon may be confusing. It might help to ask DIY posters how much they already know about hydronic heating. Sorry if this sounds condescending but I am just trying to help. As an electronics engineer, my family often tells me they don't understand my explanations of electronic stuff :-) Sometimes I just take for granted that everyone knows the technical stuff that took me 40 years to acquire.
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I would first test the in slab tubing to see if it flows and will hold pressure. Once you have confirmed that you have something serviceable to work with, start making a plan to repipe it all. The piping size and arrangement you have will never work and needs to be scrapped. I would suggest reading the Idronics link provided in the other post and start making a plan. Do you know what type of tubing you have? Right now the heat exchanger is part of the heat system. Do you need it to be? What model is the heat exchanger? How many zones? What model are the pumps?
"If you can't explain it simply, you don't understand it well enough"
Albert Einstein1 -
Best and cheapest option - hire professional plumber who have good experience in radiant floor system installation. Before his start do anything-ask him to show you what his have done before. Also ask which software plumber use to design radiant systems-if his don't use any one-not sure can this person know what they do. ( mostly plumbers use Loop Cad to design radiant system).
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I had the job of restoring a radiant floor system for a new owner of a previously foreclosed residence that spent several winters unoccupied. There were multiple frozen pex lines in the floor both within the home and in the garage area. Finding the frozen lines meant isolating each circuit and pressure testing with compressed air. Locating the leak took more time using a Big Ear sonic listening device to survey the floor slab and focus on the area where the escaping air was the loudest. It took a 1/2" SDS Max hammer drill to break up the floors and patch the frozen sections. Not my favorite job but still possible. Do not waste time installing your boiler until you know which circuits can be operated and which still need to be isolated for a future repair.
Small persistent leaks once the system is up and running might be managed using Hercules Boiler Liquid (available from www.Supplyhouse.com as well as most boiler supply houses). However, getting a successful seal on an open system connected to an atmospheric boiler will require isolation from the boiler and recirculation with the floors at pressures in the 30 to possibly 60 psi range.
Another solution I've used for small persistent leaks on older radiant sytems is a solution called Loop Conditioner. My source is for geothermal loops but this solution was initally created for leak sealing of Pex piping in RVs, spas and swimming pool piping systems. It appears more like a liquid latex solution that needs to be recirculated under pressure in the radiant floor loops while isolated from the atmospheric boiler. I've used it twice to seal minor underfloor leaks in old polybutylene floor heat installations made back in the 70's and they are still holding up with no fluid loss.
Underground and in-slab leak detectors can be very expensive some sonic units on Amazon might be had for under $200 but the professional ones for leak detection will run well over $2,000 so depending on your access it might be experiment with a budget model or find a rental source for a professional one. If business call American Leak Detection is within your area they too have the equipment for finding in-slab and underground leaks an may be worth a try.
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Based solely on this picture, for anyone to speculate as to what needs to be done, is a complete waste of every ones time. What the homeowner needs to do is hire a competent mechanical contractor to visit the jobsite and get the full picture and figure something out. Do not even try to fix it yourself.
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Just call a reputable heating contractor with basic knowledge of radiant systems. Left to myself, I believe I would start by stripping all of that superfluous piping back to the point where we had just the supply and return manifolds and then air test all loops to insure, at least those are all viable. And then cross your fingers that those loops are the correct length. Then the repiping scheme for proper boiler piping, temperature control and zoning would be up to said reputable contractor. This depending on his personal preferences and choice of boilers. But, given the location of that T-87F base plate, my guess is work of a rookie. That being said, I would take every necessary step to insure the viability of the existing loops.
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