circulating pump

My hot water circuit from the boiler that heats my indirect domestic hot water heater has flow through it any time one of the heating zones has flow regardless of whether it's separate circulation pump is running, causing my domestic hot water to heat to 180F and has now ruined the relief valve...

Hey guys, I just bought a 20y/o house with an oil boiler and three heating zones. From what I can tell, there's one circulator pump for all three zones and three zone valves (there's another circulator pump which I'm not sure what it does. It is also a bit noisy but not much). One of the pumps...

Forgive me if this has been addressed elsewhere; I did a cursory search but didn't see anything helpful. I have Rinnai - 69K BTU - 95.5% AFUE - Combi Gas Boiler - Direct Vent (Model: E75CN) water-heater for my radiant heating system (and domestic hot water). When the thermostat calls for heat...

I need help with a hot water heater system in a new construction. We are going with a 50 gallon heat pump water heater with a tank booster and a recirculating pump. The plumbing company is putting in the return hot water lines for the pump but expects me to provide the water heater, pump, and...