Reason to Pull Check Valves out of Recirculation Pumps

[BirchwoodBill]

I am reviewing the one document done by the last professional who installed the Warmboard manifold 18 months ago. He walked off the job with the heat not running leaving me to hire another person to install new valves to bleed the air out of the system. Two of the three Honeywell Zone Valves also have bad end-switches - (Yes the original contractor did get paid without the heat running in the house).

The document (attached) left by the original contractor has the instructions to "Pull Check Valve" out of the two recirculation pumps (Grundfos UPS15-58FC). However, I don't see the "Check Valve Removed" label on the name plate of the pump. So I don't know if it was pulled or is still installed. The larger question is what is the reason WHY the check valve would be pulled out of the two pumps. The indirect has its own Taco-007-ZF8-9 pump.

Trying to determine if I can re-use the pumps when I upgrade the boiler to a mod-con and move all of the CH over to the manifolds (Rehau Pro-Balance).

 

[NY_Rob]

If he did discard the built in flo-check... you can get a replacement for about $10 from supplyhouse.com, or you can get a much better inline flo-check from Caleffi:
https://www.caleffi.com/usa/en-us/catalogue/line-flow-check-valve-na51059

 

[Sponsor]

 

[BirchwoodBill]

Interviewing contractors for replacement project. was told it is common practice when using a circuit with zone valves. It cuts down on flow loss.

 

[Dana]

That may be a common practice and a common rationale for it, but it's not the right thing to do. Most systems are way over-pumped to begin with, and removing the check valves causes back-flow on other zones when just one pump is running.

 

[NY_Rob]

If your thermostats control your zone valves directly (which is common/accepted practice in small-simple systems), the zone valves stay open if they were on a heat call when the DHW priority call came in. You will get reverse flow in that situation if the flo-checks were removed.
I'm not a big fan of the IFC (built in the the pump) type flo-check, I prefer the flange or inline type for numerous reasons.