2 cold radiators, rest are fine

[Plump82]

This morning I realised 2 of my radiators are stone cold (they were fine last night) I've bled all radiators in my flat but that's not made a difference. I assumed this might be an airlock but online suggests I wouldn't have hot water from the taps which I do. I'm now thinking I might need them flushed but could the radiators go from hot to cold that quickly?

Also if they do need flushed what does this entail? I have house cats so wondering what the logistics of this will be? Will the plumber need in every room with a radiator?

Not sure, but do the have TRVs on them? They can go wrong.

One does and one doesnt.

I had one radiator that was cold and found a video one YT that talked about the outlet(?) valve on the opposite side of the radiator to the TRV being stuck. I took the cap off that and put WD40 on it and that released it and sorted the problem. Might be worth a try before paying for a plumber

Just think it's strange that 2 have went cold at the same time.

Not a plumber I'm afraid, that's just what worked for me. Maybe yours are in series and one is blocking the other?

Could be the pump losing its ooomph. Some pumps just pack up and others slowly give up.
Whilst it depends on layout and location of the pump, if the cold radiators are say downstairs and the hot upstairs or if its the farthest radiators that are cold then that would be a good indication that it is the pump.

My plumber said it could be air bubbles. Told me to turn all the other radiators off, wack the heating on high and it might fix it. Worked for my individual ones not working

Well got up this morning and another one isn't working. That only leaves the one right next to the boiler working. We have another 2 that we never put on (spare room and kitchen)

That might be it. We're in a flat so all one level but there furthest away one was the first to go cold and it's worked it's way closer to where the boiler is and now the only one working is the one right next to the boiler.

Sounds to me like something is obstructing the flow in the pipes - possibly sludge. How old are the rads?

This worked to fix 2 of my radiators.

Not too sure. We've been there 7 years but we weren't told when they were installed. I'm assuming I'll need a chemical flush with that. Any idea of the upheaval?

Radiator power flush causes no upheaval, and if any rads need taking off the wall clear out it’ll be a minor inconvenience. Think the price will be a days labour ish so £250 - £400 depending on where you are in the country I imagine.

It's more coordinating the cats if any do get taken off. One will freak and the other will be trying to get in on the action!!!

So they shouldn’t need to take any off if doing a power flush.

https://trustedtraders.which.co.uk/articles/quick-guide-central-heating-powerflushing/

We've got a plumber coming out to assess so we'll see what he says. Typical it's absolutely freezing today, thank goodness for heated blankets!!

Thanks for everyone's advice. It was the pump that had gone. For as long as we've been here the boiler was fairly loud but as I've only ever lived in houses with electricity or the boiler being in the garage at my parents and me not taking much notice so had nothing to compare it to. Clearly it was working hard with very little output as this new one is almost silent and the radiators are much hotter!! Plumber did say it will be worth a flush at some point too but for now we have heat!