Outdoor Wood Furnace Info
All-Purpose OWF Discussions => Plumbing => Topic started by: schoppy on May 10, 2015, 09:57:43 PM
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Any recommendations from you veteran boiler users/installers out there? What are the possible options for hooking up three loads in a home being fed by a 1 inch pex line. The loads are a 10 plate water to water for domestic hot water, a 20 plate water to water for an in floor heating system and a water to air coil for a forced air heating system. Not sure what would be the best plumbing option, manifold style or mono-flow tees or ? Thanks.
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How far apart will these 3 heat exchangers be from each other?
If all in the same general area, I would use either a 20 and a 30 plate or two 30 plates and put everything in series.
If they will not all be close together then it depends on the layout.
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I would definitely agree with RSI on this, upsize the plate exchangers, more than likely you could get away with them in series but I think I would use a primary loop with mono flow tees or more circs on the loops.
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I would ask a different question; do you have to have 3 heat exchangers? I realize you have to have seperate for DHW and heating, but I think you coudl get away with a side arm and a single FPHE, just an idea.
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I put in the OWB to heat my 50x60x16 (very well insulated shed with in-floor radiant using a 40 plate) and decided if I was going to keep burning wood I wanted everything on it for maximum savings. I have two Geothermal heating systems in my house, one water to air and one water to water. This year I did not hook up the water to water system but would like to next year. Both the heating units and the DHW are within 15 feet of each other in the same room. This years system was the 10 plate DHW in series with a 22x25 air coil (used a large coil to prevent air pressure drop across it) and it worked very well. It had a delta-t of approx. 25 degrees with the shower running and heat on high. The water to water geothermal system uses a 40 gallon buffer tank and I could hook up a 20 plate to this, use the existing pump for the buffer tank and disconnect the compressor for the geothermal to pick up this load with the wood boiler. I want to avoid excessive delta-t back to the boiler and slimjim has been helpful with many of my questions regarding this also. I can only find monoflow tees in a 1x1x3/4 configuration and am not sure if this would allow enough flow on my current loads which utilize 1 inch fittings. One other problem that happened on shut down this spring was several shark bite fittings I used leaked loosing a lot of my water/antifreeze. What fittings do you guys use? I used the push fittings because it appeared they would have the least flow resistance. Do regular pex crimp ring style fittings affect flow much? Oh, slimjim, I was off on my wood usage also. Best guess is this years wood usage was 11 to 13 full cords of hard wood and I didn't start the boiler until December. Sooooo what do you guys think or how would you hook these loads up in your home? LittleJohn, sorry but I don't know what FPHE stands for? Thanks for the help.
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I'm going to let the others have their input schoppy except that FPHE stands for flat plate heat exchanger or otherwise known as a water to water exchanger, Thanks for the kind words!
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There are multiple ways to to set it up and they all have advantages and disadvantages. I think at this point, it is best to decide which way you prefer so we don't keep giving you conflicting info and then we can continue from there.
You may have noticed I prefer to keep thing simple. As long as there is not too much in series, it can sometimes be able to run on a smaller pump/flow rate and usually cheaper and easier to setup. Going with a more complex system with manifolds, etc (talking about main loop, not floor manifolds) has other advantages over series setup.
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Any recommendations from you veteran boiler users/installers out there? What are the possible options for hooking up three loads in a home being fed by a 1 inch pex line. The loads are a 10 plate water to water for domestic hot water, a 20 plate water to water for an in floor heating system and a water to air coil for a forced air heating system. Not sure what would be the best plumbing option, manifold style or mono-flow tees or ? Thanks.
No matter what you do, you shouldn’t have a problem with it. I’m heating DHW, using a water to air HX in the furnace and a 30 plate on my snow melt system all being fed with Logstor and a Taco Delta T pump. Since going from “1 pex” to the Logstor the Delta T pump has no problems keeping the T at 20 or less.
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Any recommendations from you veteran boiler users/installers out there? What are the possible options for hooking up three loads in a home being fed by a 1 inch pex line. The loads are a 10 plate water to water for domestic hot water, a 20 plate water to water for an in floor heating system and a water to air coil for a forced air heating system. Not sure what would be the best plumbing option, manifold style or mono-flow tees or ? Thanks.
No matter what you do, you shouldn’t have a problem with it. I’m heating DHW, using a water to air HX in the furnace and a 30 plate on my snow melt system all being fed with Logstor and a Taco Delta T pump. Since going from “1 pex” to the Logstor the Delta T pump has no problems keeping the T at 20 or less.
Putting a 10 plate, and 20 plate in series will require a very large pump if it can even be made to work at all and supply enough heat. If the 10 plate is going to be used it would be best to put it on a secondary loop and it's own pump. That is the only way I will ever use 10 plates anymore.
Other than that, there are a lot of ways it can be done and work fine.
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mlappin what is a logstor you are using? I haven't heard of this before. I looked up the Taco delta T pump and it sounds like a good pump.
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http://www.pexflex.net/index.htm (http://www.pexflex.net/index.htm)
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Any recommendations from you veteran boiler users/installers out there? What are the possible options for hooking up three loads in a home being fed by a 1 inch pex line. The loads are a 10 plate water to water for domestic hot water, a 20 plate water to water for an in floor heating system and a water to air coil for a forced air heating system. Not sure what would be the best plumbing option, manifold style or mono-flow tees or ? Thanks.
No matter what you do, you shouldn’t have a problem with it. I’m heating DHW, using a water to air HX in the furnace and a 30 plate on my snow melt system all being fed with Logstor and a Taco Delta T pump. Since going from “1 pex” to the Logstor the Delta T pump has no problems keeping the T at 20 or less.
This was assuming of course that you either use mono flo t’s or separate circulators as needed off the main loop.
My system is set up in series, I run into a sidearm first, then to the air HX and the snow melt is last, all are 1” id ports so no restrictions.
Matter of fact my 30 plate actually uses 1 1/4 ports and I used stainless reducers to get down to 1”.
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Thanks for the link RSI, I did know about the Denmark pipe. I agree with you on keeping it simple if I can keep a good delta-t. That is what I am trying to do.
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The reason I like series when possible is because if you run parallel 99% of the water that goes through the DHW heat exchanger goes right back to the boiler without being used. Only time it is used is when you have water flowing through the domestic side.
A sidearm in more of a continuous load because it takes so much longer to recover and can work ok with much less flow.
The other heat exchangers are similar but they are more continuous so you aren't circulating water for no purpose as much.
As long as you have the same GPM on the system, you will have the same delta T no mater what configuration you go with.
What is the total length of pipe in your system and how many fittings? What size pump?
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Another way to control the return temperature is to install a Thermostatic by-pass valve, as is recommended by Central Boiler.
...basic theory is to not let any water go into a heat emitter, unless the water coming from the OWB is above 140f
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From the OWB to the house is about 75 feet (1" pex). I used all push fittings which I will probably be replacing as some of them leaked and I don't want that again. One 90 elbow on the supply just inside the house wall before the strainer and pump then 90's at the 10 plate and the air coil with one more 90 on the return line at the house wall again. The pump is a B&G NRF-36, 3 speed. Is my 1" pex going to be big enough for a 10 plate DHW, a 20 plate for the in-floor and the water to air coil on the furnace? The shed is 175' and heats a 40 plate water to water for my in-floor (this had a pretty large delta-t). Thanks.
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The 10 plate is more restrictive that all the pipe in the system.
Are you just adding the floor heat and the rest is all existing?
Will the floor heat be heating an area that was heated before with forced air or somewhere that was previously not heated by the boiler?
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When you say 90’s I take it you’re referring to the pex fitting 90’s? Short and sharp bend like a pipe elbow?
Like RSI pointed out, the 10 plate adds a LOT of restriction and the short nineties add more.
In the shop setup I used long radius copper elbows, takes up more room but a lot less retriction.
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The more I read the more I learn. I would have thought the more plates the more restrictive but you are saying just the opposite? The floor heated area is normally heated by a 46,000 BTUH water to water geothermal system, it would be additional load on the owb if I added it. Right now all of my fittings are 1" push fittings including the 90 degree elbows. Would 1x1x3/4 monoflow tees work for the 10 plate and 20 plate if I added the 20 plate in? Do you normally do the first in last out for the piping of the monoflow tees? Or should I look at changing out the 10 plate? RSI, I see you are from Wisconsin also, I'm just north of Portage. Thanks guys.
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Once you reach a certain size in your plate exchanger’s they go up to one inch fittings, go with even more plates and they go up to 1 1/4” fittings. Most if not all of 10 and 20 plates I’ve seen listed only have 3/4” ports.
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All the plates are in parallel so the more you add, the less restriction. The port size has little to do with it. A 3/4" threaded fitting will be larger inside than a 1" pex fitting.
Most 5x12 heat exchangers have a minimum of 1" threaded but some 20 plates have 3/4" on the side for the DHW so less adapters are needed.
Since you are adding more heat load, I would go with two 30 plates in series. It will keep head pressure to a minimum and should increase the flow by a couple GPM over what you have now.
If you went with two 20 plates it might be ok but bigger is better on heat exchangers.
If you want to try another brand of push fittings, I have a couple Copperhead brand elbows that I ordered for someone and then they decided to use crimp instead.
I am in Columbia County too.
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All the plates are in parallel so the more you add, the less restriction. The port size has little to do with it. A 3/4" threaded fitting will be larger inside than a 1" pex fitting.
Most 5x12 heat exchangers have a minimum of 1" threaded but some 20 plates have 3/4" on the side for the DHW so less adapters are needed.
Since you are adding more heat load, I would go with two 30 plates in series. It will keep head pressure to a minimum and should increase the flow by a couple GPM over what you have now.
If you went with two 20 plates it might be ok but bigger is better on heat exchangers.
If you want to try another brand of push fittings, I have a couple Copperhead brand elbows that I ordered for someone and then they decided to use crimp instead.
I am in Columbia County too.
Depends on what your line sizes are though, I went with the Logstor for more flow, I still need to work on the stuff in the house, but in the shop it’s all a minimum of 1” copper so I could get the flow without having to use a higher capacity pump.
Be a shame to install Logstor then cut the flow down with a 10 plate that only had 3/4” ports.
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My 10 plate does have 1" ports. Replacing my 1" pex lines is not an option for me, not going through that again as I buried my lines 6ft deep and ran a potable water line at the same time. I was looking at changing my push elbows to long radius 1" copper with sweat to crimp adapters. We'll see what Shark Bite says about their fittings leaking. Their literature says they are rated for 200 psi and 200 F and I know my boiler never saw 200 F.
RSI when you say two 30 plates in series do you mean using monoflow tees or just piped in series because I would still have my 22x25 water to air coil down stream of the two 30 plates? I looked up Copperhead fittings and they look good but reluctant on push fittings now. How does supply temp drop across a 10 plate versus 30 plate compare for the same load? Are you a dealer in Columbia county?
Has anyone ever measured the I.D. difference between the stiffener for 1" push fittings versus 1" crimp? Wondering how flow compares between the two?
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I never use Monoflow tees so I am not sure how well they work. I meant just in series. You may want to put bypasses around each heat exchanger so you can isolate them if necessary.
Another possible way that might work better is to put the floor heat exchanger and water to air heat exchanger in parallel after the DHW heat exchanger. It depends on the piping and heat load on them if this would be better.
If you had Sharkbite brand fittings, I wouldn't bother trying any other brand. What brand is your pex? Yes, I am a boiler dealer in Columbia County.
The size of the stiffener in the sharkbite fittings will be close to the same as the crimp fittings. It may be slightly larger but not much.
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My piping is Rehau 1" PEXa (red) oxygen barrier running from the boiler to the house and shed. It is Rehau 1" PEXa non-oxygen barrier (white) in the house and shed. It is my understanding that 1" PEX a,b or c are all the same dimensions but use different processes to cross-link the plastic.
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Since you have PEXa, you can use the expansion type fittings. They do require special tools but the Rehau Everloc fittings are much better than anything else. The Wirsbo style expansion can also be used but they aren't as good as Everloc but do have the larger inside diameter. I saw Menards is now selling the Wirsbo style and the tools are cheaper than for everloc.
Regular crimp fittings are going to be a lot cheaper and won't restrict that much unless you use the pex elbows. (and a lot of them)
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Since you have PEXa, you can use the expansion type fittings. They do require special tools but the Rehau Everloc fittings are much better than anything else. The Wirsbo style expansion can also be used but they aren't as good as Everloc but do have the larger inside diameter. I saw Menards is now selling the Wirsbo style and the tools are cheaper than for everloc.
Regular crimp fittings are going to be a lot cheaper and won't restrict that much unless you use the pex elbows. (and a lot of them)
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Thanks everyone. I talked with a Rehau rep today and he recommended their brand of course but I will have to check them all out. Need to do a few checks that slimjim also recommended and have my water tested again after loosing a lot of my treated water. One other note, I contacted Sharkbite also and one rep told me that all their fittings have the shark imprint on them if they are sharkbite brand fittings.