House not getting Warm

[dgrallying]

i have recently been having some issues with my heating due to a sticky 3 port valve, i have now changed the valve and the heating seems to be working fine however the heating does not seem to get above 21 degrees.

i have checked the rads and none seem to have any air in them so i know thay are all getting hot, but for some reason it will not get hot, i have even turned the boiler right up.

have you got any ideas?

 

[twgas]

if rads are getting properly hot then the system is working, could the rads be too small for the rooms, the TRVs shutting down or the room stat getting up to temperature and shutting off.

 

[dgrallying]

never had the problem before, the rads haven't got TRV's and the room stat seems to be working fine.

could it be something on the boiler?

the boiler is a Potterton Kinghisher MF cf80

just in case you ask the pump is working fine and i have flushed the system

 

[bengasman]

well, it has been pretty nasty cold, more so than usual for the time of year.

maybe the roomstat is not working a hundred percent after all.

could be it is the old open vent problem