2 geothermal heat pumps, one water pump, csv

[bluegrill]

I have 2 Water Furnace units, both 3 ton. One is 20 years old and one is 2 years old (Envision). I have  a 1 hp pump which delivers about 12 GPM which is enough for both units. It is an open loop system. When the older unit runs by itself the water pressure is about 30 psi. When the newer unit runs by itself the water pressure is about 15 psi. When both units run the pressure is about 10 psi. If I were to put a cvs on the pump and adjust so the pressure stays at 20 psi whether any combination of 1 or 2 units running, does the csv cause the flow rate to go down. Especially, if the older water furnace unit, which is now seeing 30 psi, sees 20 psi after the csv will it be getting fewer gpm's. I hope I have explained my question clearly enough. I guess a simpler way to put it is, when using a csv to REDUCE pressure, does it also reduce the flow rate.

[Cary Austin]

When you reduce the pressure through anything, it will reduce the flow rate.  The heat pump will have more flow through it at 30 PSI than it will at 20 PSI.  The only way a Cycle Stop Valve would reduce the flow is because of friction loss through the CSV.  With a CSV1, the friction loss at that flow is almost not measurable.  With the CSV1W or CSV1Z, the friction loss may  reduce the flow from the pump a slight amount.  In other words, when both heat pumps are running and the pressure is usually 10 PSI, a CSV would give you a pound or two less pressure.  

I think I see your problem.  I believe your best solution maybe to use a CSV1 that holds 10 PSI.  In this way when your heat pump is only running one zone, you will have the same pressure as when both zones are running.

[bluegrill]

Thanks for the response. You recommend a csv1 holding 10 psi. I don't see that product anywhere. The csv1 seems to be preset to 40, 50, or 60 psi. Did you mean csv1z?

[Cary Austin]

No, I can do a CSV1-10.  Lots of things not in the book.  Call if you want.  800-652-0207  8-5 M-F
Thanks

[WF_Inc]

bluegrill,

We apologize for not responding earlier, as we only discovered your post today.  We trust that you have been in contact with your installing contractor, in regards to your concerns.  However, if a resolution has not been found, please feel free to contact us, as we will be more than happy to work with you and your contractor.

WaterFurnace International, Inc.