New Boiler, Now Two Radiators Don't Work

anotheruser

Quick question for some advice.

I had a new boiler fitted as the old one broke. It was on all night but two radiators are still freezing cold, despite being full of water.

I originally thought it was just being slow. Bled and re-bled the radiators in the approximate order from the boiler but the last two on the loop seem not to want to have hot water.

The others are working fine. These two used to work fine also.

Any advice on what might be causing it and how I can check?

pmartin86

Sorry if this seems like an obvious statement, but are they turned on? most radiators these days have valves on the radiator itself so you can turn them on/off as needed?

anotheruser

Yep, all turned on, valves open and boiler on and working.

booty40uk

Installer should have checked that all rads and hot water outlets were working correctly as part of the commission process.
Try turning off the ones that are hot and see if it sorts it out. System will probably need balancing too.

anotheruser

That's a good idea; Will try it.
For secret reasons, the installer didn't do that. They didn't even bleed the radiators.

WTFH

Check the system pressure.
Alternatively, it could be a sticking valve. Were they screwed off tightly over the summer? If so, encourage the valves at either end of the rad with a "gentle persuader"

I_have_spoken

COuld be debris was dislodged when the boiler was decommissioned and has blocked the pipes.

Often a power-flush is mandated before the warranty on a new boiler is valid.

southcoastrgi

sounds like an air lock, as booty said turn off the other ones & see what happens

anotheruser

Just a quick update:

I turned off all the others and left the two on. What do you know, hot water flowing lovely. So I open up all the others one by one and now they're all working

Thanks for the help!