2 radiators stone cold ....

Ebe_Scrooge

Sammy_Dee wrote: »

no, done nothing else with them at all. I'm hoping it is just a sticky TRV! I don't want the £300 cost of a power flush!!!!!

If it IS sludge that's causing it, you can try a DIY approach before the expense of a power flush. Make sure the heating is turned off, then completely close both valves on the radiator. Get a bowl handy and undo one of the nuts where the pipe enters the radiator. Catch the water that comes out in the bowl. If you open the bleed key this will make the water come out faster.

The water will only be coming out of that one radiator, so it won't be gallons. When it's pretty much empty, undo the nut on the other side, release the pipes and lift the radiator off the wall. Tip it up slightly to drain out the last of the water..

Carry it outside and give it a really good flush through with a hose, until the water runs clear.

Give the threads a good clean with an old toothbrush, then refit the radiator and refill it ( keep an eye on the pressure gauge if you have a pressurised system, top up as necessary ).

Repeat for every radiator if you think they're all sludged up.

Finally, check all the connections for leaks, restart your boiler and bleed the system as necessary.

It's not quite as good as a power flush, but it costs nothing. It sounds complicated writing it down, but it's actually a very easy process, if a little time consuming. Saying that, I've done a whole house in about 3 hours or so, it's not too bad ( worth having an extra pair of hands, though, radiators are quite heavy ). And like I say, it costs nothing to try :-)

Dave101t

couldnt it be the other valve, the one which doesnt have a screw cap on it? if the feed to the radiator is off, then all linking pipes will stay cold as described.
(this confused me for 2 weeks when i had 2 dud radiators with no other issues)

latecomer

It shouldn't be unless they have been closed. The TRVs can shut off themselves (or be turned off) and hence easily get stuck. The other end (lockshield) can only close if someone does it manually.

If you are going to try Ebe_scrooge's method, which we did in our house, I would make sure you have the entire system drained down first to minimise the water in each radiator and hence potential for accidents.

explumber

would suggest opening the lock shield valves fully (not thermostatic valve). you will need to count how many rotational turns of the valve it takes to open completely, so when you close them they will return to the same position.
sometimes the lock shield valves, from their closed position when first installed, are only cracked open a quater or half a turn for balancing the system. if left in this position, any sludge in the system can get wedged under the valve.
best to do this with heating running.

good luck.

Sammy_Dee

Just an update.


We had a plumber out who recommended a powerflush as he is convinced the pipes themselves are sludged up.
He quoted £460 (yeah right, Eon are running an offer £275 all in)

We told him we'd get back to him, in the meantime, another plumber (partner of a friend) suggested we try Fernox F5 first.
Drain system down, turn off all radiators other than those not working. Pump water through until it runs clear.
Then drain again, put Fernox in, refill and switch on heating.

Balance radiators, if still not working after an hour - turn off all OK rads again and just leave the dodgy ones on, see how that goes.

If no joy, open all rad valves throughout the house and leave the F5 working for a week and see how it goes, then drain and refill with inhibitor if working.

If it's still not working he then suggested the professional power flush


In theory, this is easy enough for us to do, we did renovate the place from top to bottom and we're quite au fait with DIY.

What do other people say?

latecomer

Definitely worth a try if it saves you a powerflush. We flushed ours through with chemicals (we used another brand but same idea) when we bought the house and took each radiator off and flushed manually outside. And if thats all it takes then its a cheap fix. dont forget to get some inhibitor to put back in afterwards.

To be honest if you are draining down the system anyway I'd take off the two radiators that are causing you trouble and give them a manual flush outside with the hose. Shut off all other radiators taking note of the number of turns it takes to close the lock shield valve so you can return to their original position afterwards.
Then refill the heating system but only open the TRV on one of the radiators which isn't working. Then once you have refilled the system open the bleed valve on this radiator and make sure its filling up - that should let you know whether water is getting to the radiator. If that works then open the lock shield valve and hopefully you'll get water going through the radiator. If this doesn't work then it could be a problem with the lock shield valve or the pipework back to the boiler.

Repeat for the other radiator and then hopefully once they are working you can return the rest of the system back to normal.

Good luck!

Sammy_Dee

You might be able to clear something out for me, the radiators are clearly getting water, as it comes out when you bleed them, but it doesn't get hot.

I was thinking the water was probably from before the pipes got blocked, - is that right?