new boiler working hard but not heating house enough

[thorndwt]

Hi
in summer had a new worcester condensing boiler fitted by a plumber
the hot water is hot
the rads get warm but not really hot enough
the boiler can be left on 24*7 and when its cold struggles to get the house above 17-18 centrigrade
i cant help but think somehtings not set up right

any ideas please?

i have bled the system; its got auto air bleed valves on and it is pressured to 1bar

thanks for any help!

 

[Breesey]

Where's the boiler stat set?

Do you have TRVs?

 

[gas4you]

What worcester is it?

 

[dal5band]

Generally, you can set the max HW temperature and the max CH temperature (radiators). Sounds as though yours arn't set right.

 

[bengasman]

Combi or conventional?
If conventional, set dhw and heating at separate times.
Are the rads at the bottom as hot as at the top?

 

[Slugbabydotcom]

the rads get warm but not really hot enough

Combi's generally come with the CH burner pressure set to produce about 55000btu. This is around half the average capability. It may need setting higher according to requirements. A faulty temp sensor is highly unlikely but it did happen on the first combi I ever fitted back in the eighties.
As already asked Where is your boiler stat set? That is after all what controls the temperature of the system water.

Your radiators could be undersized! a heat loss calculation will be required to check that one.

Poor flow through the system occasionally through something as daft as a valve not opened properly [I'll play my Joker on that one]
Other causes are a blockage maybe due to sludge, airlock or pump speed set too low. It should be on max!

A badly sited room stat could also cut off the heat too early. Is yours situated near any heat sources that could be giving it a false reading?