Heating pump constantly running

[mrikirkby]

Firstly i would just like to say what a great forum and there seems to be a wealth of knowledge here!

Secondly i have a couple of questions to ask.

I have just fitted a room stat to my CH system between the time clock and the boiler in doing so i noticed that my pump is running constantly should it do this or would it be better to have it shut of with the boiler ? It has always been like this.

Also the boiler cuts on and off every 5 mins or so when the room stat is set at 25c but no were near as much when it set at 20c. The rads are getting hot and all have trvs but the one in the hall is set to fully open as this is where the room stat is. Will probably remove this soon. There is also a pressure bypass in the loft.

It is an oil fired standard system closed but vented with hot water tank and the boiler stat is set to 80c, 6 rads.

The bungalow is only 2 bedroom and well insulated in the loft and doubleglazed all round.

The Idea of a room stat was to try and stop the boiler from starting so frequently as the whole system was running on TRV's.

Any help would be great and I will happily supply more info if needed.

Thanks in advance Ian

 

[Softus]

Some boilers control the pumping a manner commonly known as "overrun". I don't know if your boiler is one of those. If it is, then the overrun control might be faulty.

If not, the either your system is wired incorrectly, or you have a faulty (or sticking) motorised valve.

 

[mrikirkby]

Hi thanks for the reply, My boiler does not have an over run nor are there any valves it is just wired in to run continually and iam wondering if this is why the boiler is constantly on and off when the room stat is set slightly higher if the pump is pushing cooler water round and not letting the hotter water heat the rooms ?

 

[Softus]

It sounds like your boiler is cycling on/off according to the effect of its own thermostat, instead of responding to the demand from the room and cylinder thermostats, so you have an opportunity to introduce more controls and save money on fuel.

 

[mrikirkby]

If i lowered the boiler thermostat will that help ? Iam going to work out and try and see if the boiler is oversized.