Print

[bfmco7]

I am currently researching and trying to put together a plan to plumb and wire my heat pumps for my future boiler. I have the lines run from the house to the boiler site. I have the wires and thermostats in place for my boiler as well as the piping (did all this when I built my home.) I have 3/4” and 1/2” lines run from the boiler site to the house.

I am looking for recommendations in plumbing my DHW And air handlers. The plan is to have a pump at the stove that circulates the hot water loop and hen do a secondary loop off of that with an additional pump for the exchangers. How would I wire and plumb this system? I know there are several options.

[wreckit87]

Your underground water piping is 3/4" and 1/2" An elaboration there would be great, as 1/2" PEX won't carry nearly enough heat to heat a home and 3/4" is still undersized for most homes. Generally one would make a series loop through either a sidearm or plate exchanger for the DHW, then the air handler, then back to the boiler. 24/7 circulation with a pump at the boiler. With your second air handler, I usually tee off the main loop and add another pump for it and run it either 24/7 and balanced with a valve, or to be turned on when the secondary air handler gets the call from the thermostat. This would require a switching relay to convert the 24v thermostat signal to the 120v for the pump. Were you the guy with the second set of thermostats that asked this the other day on the Facebook page or is it coincidence?

[shepherd boy]

  I think you have a Set of 1" and a set of 3/4 " lines, at least that is the way most premade pipe comes unless you put it together yourself.  Welcome to the forum. If so, I'd forget about the 3/4 lines, just use the 1"and go to your water heater, than two tees and a secondary loop to the air handlers with it's own pump would be my suggestion. Either air handler could cut on the heat loop with a relay in the air handler and one on the pump pulling in together. Do you have fixed speed or variable speed  air handlers?

[braveblaster]

I am looking for recommendations in plumbing my DHW And air handlers. The plan is to have a pump at the stove that circulates the hot water loop and hen do a secondary loop off of that with an additional pump for the exchangers. How would I wire and plumb this system? I know there are several options.

With two Heat Pumps I would run separate and individual loops and pumps to each unit air handle.

** One loop with its own pump to feed DWH/Plate Exchanger, from there to Air Handle and back to OWB. **

** Second loop with its own pump to feed second Air Handle and back to OWB. **

I used 1" PEX for all lines.

I have the same exact set up and have each individual pump controlled by single SWs to turn them individually ON/OFF as I wish.

[bfmco7]

Yes that was me. And yes I have 3/4” and 1” lines. My mistake. 

Your underground water piping is 3/4" and 1/2" An elaboration there would be great, as 1/2" PEX won't carry nearly enough heat to heat a home and 3/4" is still undersized for most homes. Generally one would make a series loop through either a sidearm or plate exchanger for the DHW, then the air handler, then back to the boiler. 24/7 circulation with a pump at the boiler. With your second air handler, I usually tee off the main loop and add another pump for it and run it either 24/7 and balanced with a valve, or to be turned on when the secondary air handler gets the call from the thermostat. This would require a switching relay to convert the 24v thermostat signal to the 120v for the pump. Were you the guy with the second set of thermostats that asked this the other day on the Facebook page or is it coincidence?

[bfmco7]

Does anyone have a detailed diagram of how this is done and a parts list?

[schoppy]

Each installation is unique but I have a 2 Geothermal heat pump systems, one water to water and one water to air. Slim helped me out greatly and my system works great with only one pump at the boiler and one Alpha pump for the water to water heat pump. I only have one set of 1" lines coming to the house which I would have put in 1 1/4" if I had known better. Once my lines come into the house I upped the size to 1 1/4" and used a primary/secondary loop system using monoflo tees as Slim suggested. First secondary loop goes to the DHW plate. The second secondary loop goes to my plate heat exchanger for my water to water heat pump system and the third loop goes to the hot water coil for my water to air system. Basically it is like having one pump for the whole house as the Alpha pump only uses 7 watts when it runs.   

I have another set of lines to my big shed but that is completely separate from the house. Anytime I can keep the electrical use lower with fewer pumps and get the job done only makes sense to me.

[wreckit87]

Here is how I would pipe it if it were my job. Use the 1" lines from the boiler with a 26-99FC pump running 24/7 (perhaps a smaller or larger pump depending on your length of run). Through a 30 plate HX for domestic water, counterflowed from domestic direction. Mixing valve on output of domestic tank. Closely spaced tees before the first air handler with a 15-58FC pulling water to the second air handler. Balancing valve somewhere on that loop to balance flow between both air handlers, usually the isolation valve for the pump discharge works well. SR501 relay to fire the 15-58FC wired in with the thermostat and air handler, so that when the thermostat makes to turn the fan on, it also tells the relay to turn the pump on. Of course there are some variables with each system in coil size, pipe length, domestic tank size (or lack thereof), plate exchanger vs sidearm, etc. If I were designing a system for a customer it would be something like this. I did one just like it this fall and asked the guy a few days ago, said it's working great at -20F