Cold Radiators

[rosyherb]

Hi
Our dining room is always cold dispite having the radiators swapped for 2 bigger ones.
The other radiators in the house get hot but not these, they get warm at the top only, we have repeatedly bleed them and no improvement.

We have checked the thermostat and they are set right.

Also i have noticed the feed pipes aren't hot either.

Any suggestion before have to pay for a plumber.

Thanks folks

[Jomlett]

They might have air in, and need bleeding to release the air.

[ummmm]

Try turning all the radiators off and just leave those ones on.

[malagabob]

If the TRVs are on full and flow pipe is warmish possibly the TRVs are stuck. You can take the heads off to see if that makes a difference. Or do as Ummm says turn off all others to direct all flow to those rads. Possibly whoever fitted the new rads never balanced the system.

[rosyherb]

Thank you will try taking the TRV off, i did wonder about that but was worried i'd end up flooding the place, google also suggested that the pump might not be man enough, hence turning off others might highlight this... thanks makes sense now.
cheers folks.

[The Builder]

If the rads are getting warm at the top, it suggests that the TRVs are opening Ok.

Several possibilities...

All the rads need balancing. The others are possibly taking too big a share of the flow, thus these are being starved.

The layout of the pipework is such that there is not enough flow (volume of water) available to these rads... perhaps the pipework is branched off a circuit that has too small a bore (diameter.) This would be likely if minibore or microbore have been used.

The circulation pump may well need speeding up. There are usually several speeds available.

To test all this further ... turn ALL other rads in the house down to zero on their TRVs This will give all available flow exclusively to the dining room.