Hello everyone,

When I installing a recently purchased surface mounted aquastat to control circulation pump, I noticed that the boiler inlet side is higher than outlet side and thus the hot water goes back to inlet side when pump is off, however, the aquastat is installed in outlet side, which results in this problem - the hot water moves away from the aquastat so it never senses the temperature rise and never make the connection for pump to start.

I could install the aquastat at inlet side to sense the hot water before pump is started, but a new problem is, when the pump starts, the colder water (due to being at inlet side) comes shortly and shut down the pump again, so I can imagine the pump will switch on and off very frequently (called short cycle?).

To solve the problem fundamentally, I have thought of one way, i.e., switch the pump in and out and let the boiler flow in an opposite direction. In this way, the hot water will automatically (pump off) or forced (pump on) to flow to the higher side (boiler outlet) where the aquastat is installed. But not sure if this is in violation to the boiler's setup/design.

I didn't see the inlet or outlet label anywhere on the boiler.

Any comments/advice would be appreciated.

Thanks in advance,

-York

 

No, you absolutely can not change the direction of flow through the boiler.