Hi all. I’ve got a Baxi 400 heat-only boiler (located in the garage) with an S-plan htg/DHW set up. The pump is located in airing cupboard with the control valves and the unvented cylinder.
When we first moved in, we found the heating pump ran constantly regardless of heating or DHW demand. When the pump runs against closed valves, the pipes make a knocking which is enough wake me up/keep me awake (light-sleeper)
This was diagnosed to there only being a frost-stat in the garage (set at the lowest setting of 5 degrees) and no pipe stat, plus it being winter and blooming cold!
I’ve noticed recently that it’s doing the same thing. However I have disconnected the frost stat wiring so it cant be that, and at the moment there is no htg demand.
The last time it happened was the night before we were going on holiday and had a 3am alarm set. I turned off the fused spur to the heating which kills everything. When I woke up I turned it back on, expecting the pump to turn on, but it didn’t.
Is it possible that there is some electrical malfunction with the 2-port valve to the cylinder? The valve itself isn’t stuck as I can manually move it using the lever (and can hear water moving through it) but in my head that’s the only thing that could be switching the pump on (see below diagram)
It’s certainly giving me something to think about whilst on holiday!!!
When we first moved in, we found the heating pump ran constantly regardless of heating or DHW demand. When the pump runs against closed valves, the pipes make a knocking which is enough wake me up/keep me awake (light-sleeper)
This was diagnosed to there only being a frost-stat in the garage (set at the lowest setting of 5 degrees) and no pipe stat, plus it being winter and blooming cold!
I’ve noticed recently that it’s doing the same thing. However I have disconnected the frost stat wiring so it cant be that, and at the moment there is no htg demand.
The last time it happened was the night before we were going on holiday and had a 3am alarm set. I turned off the fused spur to the heating which kills everything. When I woke up I turned it back on, expecting the pump to turn on, but it didn’t.
Is it possible that there is some electrical malfunction with the 2-port valve to the cylinder? The valve itself isn’t stuck as I can manually move it using the lever (and can hear water moving through it) but in my head that’s the only thing that could be switching the pump on (see below diagram)
It’s certainly giving me something to think about whilst on holiday!!!
