By default, the equilibrium setting was -5c. Currently, the outdoor sensor shows -3.3c. Still the BUH is kicking in for space heating.
I tried lowering it to -7c and initially that seemed to cure it, but again, it kicked in.
According to the reference guide:
“Equilibrium temperature: Outdoor temperature below which operation of the backup heater (or external backup heat source in case of a bivalent system) is allowed”
Am I missing something?
It will still come on for defrosts if needed, and if the flow temp is below 18 afaik.
Are you tracking BUH on as a sensor so you can see when it’s coming on?
I’m not tracking it at the moment, would need to reprogram ESPAltherma.
I can see it in the input power though and can see it was coming on during heating and defrosts. I’ve turned off the (mislabelled) breaker for now. So far, it’s working just fine without the BUH.
It may fail to restart after a defrost if it’s expecting the BUH to be operational and increasing the water temp above the unit minimum…
It’s done 6 or so defrosts since, so it’s looking ok.
Thx for the heads up
