Cold radiators - totally flummoxed

gas4you

DD, turn off the rad valves, then drain the rad. Then one at a time open the rad valves and let them flow into a bucket and see what comes out. Let a couple of bucket full of water come out from each pipe.

Failing this I would reverse flush this pipe circuit.

Although extremely rare, it has not been unheard of to get a faulty radiator.

lovesgshp

dollydolittle wrote: »

Thanks for getting back so quickly - definitely no air whatsoever in that rad. The top third gets hot, not as hot as other rads in the house, but I'd be happy if I could get it to be that temp all the way down.

What else could be stuck in the valve, apart from the bit we checked following Cardew's suggestion?

Another thought, can you change the thermostatic valve from another known working radiator to the problem one. Process of elimination!!

dollydolittle_2

They came yesterday and I couldn't be here so husband worked from home. When I got back he said they had rebalanced the system!!!

I am spitting feathers and feel that they are just stringing us along. The radiator is exactly the same as it was before the 'rebalancing'. Oh, and they turned up the temp on the boiler so the other radiators are blisteringly hot now, as if I'm going to fall for that.

We established two weeks ago that the return pipe was not getting hot, that only the top few inches of the rad were getting hot and that as turning off all the others made no difference then there must be a problem with restricted flow in the return. They all stood there and agreed that this was definitely the case. And yet again they turn up and rebalance it. And say it is now fine. And leave. And it is exactly as it was. I am so upset they had better not even think of trying to bill me for yesterday! (The valve is OK btw.)

Strangely, I couldn't get them on the phone today, and no one has got back to me. I feel so stupid.

So, any ideas? I now have a completely new boiler, new pipework all the way to this rad and the rad in the room above (which are both new) and a lot less money. Obviously, I also still have a cold living room.

At the end of my tether. Beginning to wonder if I would be able to get someone else in to redo the lot and then send them the bill. Am I being unfair?

dollydolittle_2

Update: was told by someone to try turning the temp right up high on the room thermostat and let it run. I did, and there was a clunking noise from the rad in question and it got properly hot most of the way down. So maybe there was some sort of air lock that has just cleared and it'll be OK from now on. And maybe they were right about balancing it, even though it didn't get hot when we turned all the others off.

So seems I was being unfair to them, after all. I take it all back. I am very grumpy when I get cold.

Sigh, you would never think it could be so complicated, would you? Definitely going to get a wood burner in here before next winter though. Not spending another one shivering in hat, scarf, two pairs of socks and duvet while watching telly.

grimsalve

I've got a similar problem. Two radiators stay cold even though the rest of the heating in the house is fine (fortunately, the cold radiators are in rooms that we don't use much and the other radiators tend to warm the whole house up anyway).

The house is about 3 years old and I had the installation company round a couple of times when we moved in to have a go at fixing the problem but they couldn't work out what was going wrong (or couldn't be bothered)... and then they went bust. I've tried bleeding the radiators in case there's any trapped air but they are full of water (so they must have worked once?) and also removed the TRVs in case they were stuck but the radiators still remain cold.

I talked to a plumber/heating engineer recently and he suggested draining the whole system so he could investigate further but I was a bit concerned about how much this would all cost and how much damage it might cause (eg. if there's a kinked pipe). I'm guessing it could be something a powerflush might fix?

Cardew

Removing the TRVs(presumably just the top) is only one step. You need to check if the plunger is 'stuck' down. The plunger is a thin pin that has a strong spring action. With the TRV top removed it should be out(up) and you should be able to press it in against the stiff spring pressure. I have a couple where the plunger 'seizes if not used for a long while; just 'exercising' it cures the problem.

grimsalve

Cardew wrote: »

Removing the TRVs(presumably just the top) is only one step. You need to check if the plunger is 'stuck' down. The plunger is a thin pin that has a strong spring action. With the TRV top removed it should be out(up) and you should be able to press it in against the stiff spring pressure. I have a couple where the plunger 'seizes if not used for a long while; just 'exercising' it cures the problem.

Yes, I'd checked that too - I had a stuck TRV in my last house so I knew how to test it.

EDIT: I just had a quote from Powerflush - OUCH!!!!

dollydolittle_2

As you've probably read, we replaced the rads and then repiped, all of which was quite expensive and they still didn't work. We needed someone who really knew what he was doing to come and spend time balancing them properly. We had already tried to do it ourselves and didn't get anywhere, and actually everything pointed to them not needing rebalancing, but that is indeed what seemed to fix it.

I'm not sure such people are easy to find, but maybe if you ask around. Interestingly, it was a builder who we had round for something else who was absolutely positive they hadn't been balanced properly even though my heating engineer said they had.

grimsalve

Could someone possibly explain what exactly is "balancing"? The installers said they had done this when the system was installed (even though 2 of the radiators don't work) but I thought it would just involve fine tuning the radiator valves to even out the temperature a bit.

What would be a typical price and how long would it take to carry out a complete balance assuming there's nothing wrong with the pipes, valves, radiators, etc. (fingers crossed!).

dollydolittle_2

Someone who does this for a living will, I'm sure, tell you exactly what it is. But basically you are right.

As far as I understand it, the hot water flows from your boiler and gets to some rads first (our rads are off two manifolds with the exception of the two rads that weren't working which we replumbed bypassing the manifold entirely) anyway the other rads were taking all the water and not leaving enough for the two cold ones that were last. Balancing involves restricting the flow to the hot radiators by adjusting the valves so that there is more for the cold ones.

We haven't had a bill yet, and I am hoping we don't get one as it should have been done as part of the original boiler installation. Unfortunately, I wasn't here at the time either, so I can't tell you how long it took.