Underfloor heating boiler pump always on

[batty_1]

Hi. Newbie question, couldn't find a similar one.

When my underfloor heating pump is on, the pump on the combo boiler is also on, this is both when the boiler is calling for heat or not. So, gas light on boiler pump on, gas light off boiler pump on. (Worcester Bosch greenstar 30cdi)

Is this behaviour correct, it seems a waste to have the boiler pump on when the underfloor is not calling for heat but is on.

Hope that makes sense.

Thank you

 

[oldbutnotdead]

The boiler doesn't call for heat, the heating controllers call for heat and the boiler fulfils that demand.
The underfloor pump shouldn't be running unless one or more of the underfloor heating controllers is calling for heat. The boiler being active when underfloor pump is active is correct, it is likely that the boiler itself is not firing all the time because of the lower temperature required by the UFH.
You need to have a look at whatever is controlling the UFH, ensure it is working properly and isn't programmed in a doom loop (unachievable objective)

 

[batty_1]

Hi thanks for your reply. The underfloor heating is just in one room (kitchen extension) and it calls for heat when below the thermostat setting.

When the water temp reaches 50 (or thereabouts ) the boiler light goes out but the pump on the boiler and the underfloor are still running as the temp in room is still below thermostat setting.

When temp reached all turns off

I assume from your response that my system is working as it should.

I was concerned the boiler pump may be consuming electricity for no real purpose as the pump on the ufh should be doing the pumping round the pipes of the ufh.

 

[Johntheo5]

Is this behaviour correct, it seems a waste to have the boiler pump on when the underfloor is not calling for heat but is on.

If the UFH heating only is calling for heat then both the boiler pump and the UFH pump should both be on, the boiler may not be firing continuously but the burner may be cycling on/off.
If there is no demand for UFH then both the UFH pump and the boiler pump should stop but the boiler pump may run on for a few minutes after the UFH demand ceases.
Are you saying that the boiler pump is on continuously?

Just saw your post above.

 

[oldbutnotdead]

Hi thanks for your reply. The underfloor heating is just in one room (kitchen extension) and it calls for heat when below the thermostat setting.

When the water temp reaches 50 (or thereabouts ) the boiler light goes out but the pump on the boiler and the underfloor are still running as the temp in room is still below thermostat setting.

When temp reached all turns off

I assume from your response that my system is working as it should.

I was concerned the boiler pump may be consuming electricity for no real purpose as the pump on the ufh should be doing the pumping round the pipes of the ufh.

Yep, it's all good, working as it should. Modern pumps consume very little power, the boiler pump is sending heat in the pipework to the UFH pump so it has heat to circulate under the floor.