Adding second pump

[hardy steve]

My H2is an older model and is only set up for one pump.I'm wanting to heat detached garage next year.Here's options 1) weld a second nipple on the owb amd attach second pump and ball valve and move on.Or 2)T the 3/4 nipple above pump now and run a second pump that way.My pex now from owb to hx is 1/2". The 3/4" nipple could handle another pump with 1/2" line,but what happens if house pump comes on at same time.You know in the winter it would happen.Would increasing the 3/4" nipple to a 1" bushing then T off with 1" line to both pumps help.

 

[RacerX]

Steve could you post a sketch of what you want to do?

 

[carpenter383]

I am heating two buildings with one pump, here is how mine is set up. Water pumps to a zone valve at the furnace, then out to the HX in the garage and back to the boiler. So it is just 1 loop through both places. The zone valve in the house bypasses the furnace HX until the thermostat calls for heat. In the garage the water always runs through the HX, and the thermostat kicks the fan on and off. I'm using about a 200 ft run of 1" pex.
This may not be feasable for your set up, but I thought it would be worth mentioning.

 

[hardy steve]

 

[rx7145]

I would go with a 1"3/4"1" fitting. And run 1" to the pumps. I did this on my CB and it works good.

Still 3/4 should work as well.

 

[mtfallsmikey]

1/2" is too small....

 

[ericjeeper]

No way on this earth is 1/2 inch pex going to flow enough btus to heat a moderate to poor insulated shop of any size.
Surely your house is not heated with just 1/2 loop now?

 

[endmill]

H-2

I also have a h-2 but I have a heat exchanger coil on the top. Do you? you can run a 2nd loop of of it.

 

[mtfallsmikey]

No way on this earth is 1/2 inch pex going to flow enough btus to heat a moderate to poor insulated shop of any size.
Surely your house is not heated with just 1/2 loop now?

I've posted these before, but it never hurts to revisit pipe sizing guidelines:

2-4 GPM = 3/4" pipe
4-8 " " = 1" " "
8-12 " " = 1 1/4" "

head loss: multiply length of longest run X 1.5 (fittings, etc.)

 

[hardy steve]

I had posted me using 1/2"earlier this spring on my owb install.I got it from a friend left over from his radiant job.I didn't ask before I installed it.But it works great i couldn't be happier.I even have it running my dhw.I figure if it heats my home at 38'.It has to heat a 12x30 shed that is only 10' from the owb.