Print

[schoppy]

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.

[RSI]

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.

[slimjim]

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.

[LittleJohn]

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.

[schoppy]

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.       

[slimjim]

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!

[RSI]

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.

[mlappin]

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.

[RSI]

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.

[schoppy]

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.

[RSI]

http://www.pexflex.net/index.htm

[mlappin]

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”.

[schoppy]

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.
 

[RSI]

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?

[LittleJohn]

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