I have mine set quite high, and because all my towel rails have no TRVs on them, it does allow me to extract the heat. If the boiler has heated the water, I might as well have it. But there is a balance to be struck between the cost of running that pump longer, vs trying to dump any left over heat back in the house.
Opentherm control of our boiler tends to keep the internal pump (within the boiler) running all day this time of year. Appears to keep circulating at very low temps, approx. 30c and fires the flame up every 15-20 mins to top up the flow temp or as needed to reheat the water cylinder. As we have the heating on all day does this normal?
Yes it does sound normal. As long as you get the balance right between an over-run that actually allows for heat to be extracted versus the cost of that pump running, you are OK. e.g. there is little point circulating 20C water round the CH loop.
Thanks for clarifying but should the boiler fan also keep running? I say this because when the boiler is just circulating water (setpoint below return temp), it is surprisingly loud, in fact louder than when the boiler is actually heating at its lowest modulation/temp. It's almost as is, the fan defaults to a higher setting than when on its lowest modulation (5kw). Although our boiler is in the garage, the noise is very obvious when within our master bedroom above. Very certain the system is fully bleed of air, and the pipework is all secure etc...
The boiler should be completely off during a pump overrun. Unless your boiler is designed in a way that the fan is trying to also cool the boiler in an over run situation.
Mine does not fire up during an overrun, but that would defeat the object of the overrun, as you say, it should be off. My pump though is frequently starting up of its own volition, often every few minutes. There is an audible whoosh as it does so. It runs for a very short time and then stops to do the same again a little while later. There is no set pattern to how often it does this. I assumed the system (OT + Evohome) was wanting heat and the boiler sensing there was sufficient to circulate without firing up but I checked on the Panel and no room or zone was calling for heat, all showing 0%. Having had a noisy old boiler making lots of kettling noises and now a nice new Intergas in a way this noise of the pump starting is more intrusive than the noise of the old boiler - and she was noisy (I am referring to the heating appliance and not a person!).Originally Posted by bruce_miranda
The problem with mine I think is the fan speed is directly related to the pump speed, and when the pump is on the fan is on! Got Ideal visiting today to check for any obvious faults.
Our pump is integral to the boiler, and the fan appears to be directly linked to the pump speed.
To me that seems odd. The fan is doing a different job and is not needed when the pump alone is on. Mine certainly isn’t. The fan is needed to extract fumes from a firing boiler.
Just had a heating engineer visit. Very much looking like a pump, not fan related issue. They believe one of the main 22m supply/return pipes is resonating sound through our ceiling which they think is being caused by incorrect clips being used, and/or a pipe touching another pipe/surface. Next step is to lift some flooring above to inspect further. Deep joy!
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