Buderus

Jamie_6

Tech support

Tim Schirch

by-pass loop with constant circulation

Hi,I would appreciate any help with this matter.I just installed a Buderus G115/34 W/a riello burner, R2107 control,room sensor and LT160 tank.My system has 5 zones including DHW.Could anybody tell me if I need a bypass loop w/flowcheck from feed manifold to return manifold?Why I ask is,when electrician came to wire system he told me it is needed to protect system from pump running w/zone vaves closed.To my knowledge,the control sends power to pump and zones on the same circuit.The zone valve on the constant circ. zone only stops when pump stops(unless my new taco esp fails and sticks closed).Do I need a bypass loop to run A constant circulation zone?
Thanks for your time Tim.

Steve Ebels

Is the pump

Wired off the 2107 HK-1 or is it running off the zone panel? The 2107 will run the pump continuous at any outdoor temp below your selected warm weather shutdown. So if that's how it's wired yes you do need a pressure bypass. If the pump is wired off the zone panel in such a manner that it only runs when you have an open zone valve you don't need it.

That said..... If you have the heating curve on the O/D reset matched pretty well to your homes heat loss, the pump will be on 95% of the time as well as your zone valves being open also. The BFU room sensor will help with tailoring the water temp to the load as well, so there will be very few times the bypass will actually be needed. BUT! it only takes one time of deadheading the pump and it can be smoked.

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