dual pumps

hollywood7445

I am thinking about running a Primary- Secondary circulator system for my radiant slab heat. I plan on using 3 pumps. One on the primary "return" loop, one on the secondary" supply "and one on secondary "return". Has anyone ever set one up like this before?

Jamie Hall

A pump on the return and a pump on the supply? No need. In fact, not really desirable at all. Put one pump of the correct size on the supply side. A pump on the return would have low pressure at its inlet -- and the pressure might be low enough to cause cavitation and a lot of noise, as well as destroying the pump. Not a good idea.

hollywood7445

I have 5 x 300' loops of 5/8 I.d. pex going to a manifold. I was going to use a 1/25 hp Taco pump.

Jamie Hall

You need a pump to circulate water through the manifold and radiant slab and mixing valve. You need a pump (I'm presuming this is p/s) to circulate through the boiler. End of story.

Figure pump sizes (the boiler probably has a recommended pump) based on flow and headloss

Rich_49

hollywood7445 said:

I have 5 x 300' loops of 5/8 I.d. pex going to a manifold. I was going to use a 1/25 hp Taco pump.

Which 1 / 25th HP circ were you going to use ? There's a few