Two and a half rads not working - help!

[Joshie76]

Total newb at this plumbing game and really appreciate any help/advice you can offer...

We have a central heating system comprised of a 'unvented hot water cylinder', a '
Vaillant wall mounted gas *thermo-compact* boiler' (which has to be topped up manually, so I guess this means we have a closed system ) and some 'rads', as you chaps here seem to call them.

Last winter we noticed that two of the radiators weren't getting as hot as they once had (both in the same room) and this year they don't get warm at all. Now we have another radiator (in another room) that is not as hot as it used to be...

All radiators have Thermostatic Valves. I've tried bleeding them all and water comes out instantly so don't think that's a problem at all...

Do the valves need replacing, and is this something we can do ourselves, or could it be something else entirely?

The system is as old as the flat, which is just over 10 years old.

 

[corgiman]

It could the valves

before we decide can you try turning the rads that work completely off and see if the heat travels to the problem rads

Also check that the non thermostatic (lockshield) valves (at the opp end to the TRV) are properly open

 

[Joshie76]

Thanks corgiman.

I turned off all the other rads and one of the problem rads did warm up a little, but not very much.

I checked the LockShield valves and they were fully opened (fully rotated in the + direction). I've since closed and re-opened them but still no joy

 

[masona]

Are the pin inside the TVR working freely,they can get struck during the summer season when not in use.

 

[Joshie76]

Thanks... but err... how do I look at the pin?

 

[masona]

You have to take the head of the TRV's depending on the type,normally by unscrewing or a small allen key type or circlip .

Once the head is off,you should be able to see a pin & push it with a screwdriver gently, if there's no movement (in & out) then it is stuck.Don't take the pin out.Try and clean it with WD-40,you might have hard water deposit on the pin.

See this also from previous post.

 

[Joshie76]

Hmm, I can't see anything that looks obivously movable... Here's a picture of one of the valves in question. It's had a good splattering with paint sometime before we owned the house but has worked for some time since.

http://www.molmorg.com/TRV.jpg

Any ideas where I need to be screwing/unscrewing??? [/url]

 

[masona]

In your top left hand picture (Top) I think I can see a very small allen key which you undo then remove the head.

The reason I know because it's the exactly the same as mine !!!

 

[Joshie76]

If you mean the small silver circle at the left - it has no shape and is perfectly circular, so not for allen keys....

I've checked the same bit on the other rads and they don't have an allen key hex shape either.

 

[masona]

I know what you're saying but it's a very very small allen key.Try a magnify glass on it to look closer.

The only thing I can think of is,been damaged with the wrong size allen key.Try and put in a small screwdriver in and see if you can undo it carefully.

 

[Joshie76]

ok... but do I need to do anything first to ensure I don't ruin my carpets when I remove the head. Should I expect any leak of any kind?

 

[masona]

No, you be should okay,but better be safe than sorry roll the carpet back (?) or a old towel round the pipe.