Pump signal switch off when the boiler switches off

[Sandy43]

At my home heating system, the pump signal is picked up from the same
point as boiler. That means the pump is switched off at the same time
the boiler is switched off. The boiler was installed by an heating engineer
about 6 years ago.

It is not connected to "over run signal from the boiler.
This means it does not give any chance to heat exchange to cool down by circulating water while boiler is not heating.

Does it do any harm to the boiler heat exchange or any other parts in the
boiler?

 

[DP]

Old boilers with cast iron heat exchangers were powered from the same point that ran the pump.

Improvement on this concept was more efficient heat exchangers and pump controlled by boiler. Often this type of boiler was not suitable for gravity HW.

If your boiler has a pump connection, it would be prudent to wire the pump to the dedicated connection. Also, hopefully you will have motorised valves to control your heating and hot water. For a S plan (if fitted) you will need to have a bypass valve installed.

Might be an idea to call the installer and quiz him.

 

[Sandy43]

This was a "Y-Plan" system before with the mid-position valve.
I had a lot of problems and I converted to "S-Plan" about couple of years
ago. Since then it has been performing very well.

It is too late to contact the heating engineer now after 6 years.
I have to think of cabling the boiler from my kitchen to Airing cupboard
as it is at quite a distance. There is not spare wire running from the boiler
to Airing cupboard at the moment.

 

[simond]

Great discussion.

Lets not forget the elephant in the room. And the boiler is a?