On several occasions during this cold weather I have been woken by a banging noise from my boiler and also steam coming out of the air vent.
After several nights of this I have done a bit of detective work and can deduce the following.
The central heating isn't calling for heat but the hot water is.
The pump is running.
There is enough pressure in the boiler.
It normally happens about 4-5 hours after the heating is switched off after I have gone to bed.
When the boiler is overheating and venting, if I make the central heating call for heat the water is pumped around the heating circuit and so the boiler stops overheating and behaves itself.
I thought the pump may be sticking, a plumber friend of mine rang Ravenheat and they said the same, as luck would have it I had a replacement pump and swapped it out to no avail.
(i have since checked and the pump is running when it is overheating)
The boiler is connected to an Ariston pressurised hot water cylinder which has an energise to open valve fitted on the hot water supply pipe from the boiler. This gets it's signal via a relay from the boiler.
The top and bottom of it seems to be that when the hot water only is calling for heat there is some form of restriction in the pipe, either the mid port valve or the valve local to the pressurised cylinder. Thus the water can't circulate and hence the boiler "boils". Now for the strange bit, it only ever happens in the early hours of the morning, once I call for heat on the heating and the boiler stops "boiling" I can turn back to hot water setting and it works fine. During the day it works fine also, although the heating will be coming on and off with regular frequency as the house is occupied.
I am somewhat puzzled and would appreciate any assistance.
Thanks
After several nights of this I have done a bit of detective work and can deduce the following.
The central heating isn't calling for heat but the hot water is.
The pump is running.
There is enough pressure in the boiler.
It normally happens about 4-5 hours after the heating is switched off after I have gone to bed.
When the boiler is overheating and venting, if I make the central heating call for heat the water is pumped around the heating circuit and so the boiler stops overheating and behaves itself.
I thought the pump may be sticking, a plumber friend of mine rang Ravenheat and they said the same, as luck would have it I had a replacement pump and swapped it out to no avail.
(i have since checked and the pump is running when it is overheating)
The boiler is connected to an Ariston pressurised hot water cylinder which has an energise to open valve fitted on the hot water supply pipe from the boiler. This gets it's signal via a relay from the boiler.
The top and bottom of it seems to be that when the hot water only is calling for heat there is some form of restriction in the pipe, either the mid port valve or the valve local to the pressurised cylinder. Thus the water can't circulate and hence the boiler "boils". Now for the strange bit, it only ever happens in the early hours of the morning, once I call for heat on the heating and the boiler stops "boiling" I can turn back to hot water setting and it works fine. During the day it works fine also, although the heating will be coming on and off with regular frequency as the house is occupied.
I am somewhat puzzled and would appreciate any assistance.
Thanks