Got an open vented system with two 2 port valves and a fairly recent ‘electronic’ pump, set to fixed speed 2.
In the recent colder weather, I turned the boiler up a bit and then became aware the boiler was singing so turned the pump to 3.
By chance noticed an icicle hanging from the expansion tank overflow. Got up In the loft and with a bit of trial and error determined that it’s pumping over, a steady trickle, when the HW is on – makes no difference if the CH side is running or not.
I’ve put everything back as it was and thankfully it’s all fine again.
Any ideas why it would only pump over when HW is on?
In the recent colder weather, I turned the boiler up a bit and then became aware the boiler was singing so turned the pump to 3.
By chance noticed an icicle hanging from the expansion tank overflow. Got up In the loft and with a bit of trial and error determined that it’s pumping over, a steady trickle, when the HW is on – makes no difference if the CH side is running or not.
I’ve put everything back as it was and thankfully it’s all fine again.
Any ideas why it would only pump over when HW is on?