Radiator/Central Heating issues

[barnsleydyson]

Evening

First of all, I've trawled this board and google for the answers to this so apologies if it's a repetiton - looks like a cracking site so I'll be here much more often to get this house of mine sorted once and for all!!

I've a couple of problems/questions.

1. Radiators banging

When the boiler reaches a certain temperature, one of the radiators in the house bangs continuously until you a) turn it off b) turn down the temperature on the control or c) turn the central heating off completely. I've bled it and when it's on it heats up quite nice but it doesn't last long! What can I do? When we had our back boiler serviced the plumber mentioned that it could be something to do with a pin but would cost a couple of hundred quid to fix?!

2. Radiator temperature

I'm only able to turn down the temperature on one of the radiators in the house. What should I do? I've considered ripping them out and replacing them with new ones but not sure if that'll do anything?

3. Control board

I've one of the old turning circle control boards on the wall. How easy is it to replace with one of the new digital ones? Is it just a case of fitting into the plate and then wiring up in the same manner?

Any help appreciated!!

Liam

 

[D_Hailsham]

1. Radiators banging

When the boiler reaches a certain temperature, one of the radiators in the house bangs continuously until you a) turn it off b) turn down the temperature on the control or c) turn the central heating off completely.

Do you have thermostatic valves on your radiators?
If so, do they have a single arrow or two arrows at right angles on the body?
If just a single arrow, is it pointing in the correct direction - towards the rad on the flow (hotter) pipe, away from the rad on the return (colder) pipe?

the plumber mentioned that it could be something to do with a pin but would cost a couple of hundred quid to fix?!

If you have a thermostatic valve, he could be referring to the pin on the body of the valve. If you remove the head of the valve (usually held on by a knurled nut - no water will come out), you will see a pin sticking out from the body. This should be up. If you press down on it and let go it should spring up. If it is stuck down, tap the body of the valve with a hammer to release it. Failing that, use a pair of pliers to raise the pin - but don't bend it!. A slight amount of WD40 can help free the pin.

2. Radiator temperature

I'm only able to turn down the temperature on one of the radiators in the house.

This also sounds like valve problems - see above.

3. Control board

I've one of the old turning circle control boards on the wall. How easy is it to replace with one of the new digital ones? Is it just a case of fitting into the plate and then wiring up in the same manner?

What do you mean by control board? Are you talking about the timer?

 

[barnsleydyson]

Hi - sorry, yes I mean the timer. I've heard you can just buy a digital timer and replace the old one?

I'll try the tips with the valves later and let you know - thanks for all the help.

Liam

 

[JohnD]

tell us the make and model of the old timer, post a pic if you can. Many of them plug onto an industry standard backplate (they have clamping screws underneath) and are quite easy to change. The manufacturers also have charts of compatibility and wiring changes from old to new. It is usually a bit easier if you get the same make again, but despite the brand badging, there are only a couple of big makers.

BTW the "rotating wheel" timers are less sophisticated, but very much easier to set and understand than digital ones. For this reason they are still made and sold to elderly or simple people. I put one on my old mum's system a year or two ago.

 

[barnsleydyson]

Hi

Sorry, I struggled with a couple of the instructions RE the banging radiator so I thought if I uploaded some pictures someone could talk the absolute plumbing novice through it.

As you can see, the rad is quite old and doesn't seem to have been 'looked after' as it were. Again, any help much appreciated.

I've also uploaded a picture of my temp control to see if I can get any digi one that can be put straight on to the backplate.

Cheers,
Liam

Radiator temp control
http://img101.imageshack.us/i/01012010288.jpg/

Valve
http://img254.imageshack.us/i/01012010289.jpg/

Radiator
http://img101.imageshack.us/i/01012010290.jpg/

Overall temperature control
http://img706.imageshack.us/i/01012010291.jpg/

 

[D_Hailsham]

The first pic shows the Thermostatic Radiator Valve (TRV). There is a single arrow on the chrome body, pointing towards the radiator. So this should be the flow pipe. You can check this. It should get hotter before the pipe at the other end.

If the pipe at the other end gets hot first the TRV is on the wrong end. Modern TRVs can go on either end.

As you can see, the rad is quite old and doesn't seem to have been 'looked after' as it were.

Only the valves look sad, the paint on the rad is OK. It's not a good idea to paint TRVs or any valve!!

I've also uploaded a picture of my temp control to see if I can get any digi one that can be put straight on to the backplate.

That's a picture of your time control. I am not sure if it uses the standard backplate. If it does, you may have to change some of the wires as terminals are not always standardized.

What sort of temperature control do you have - a room stat?

 

[barnsleydyson]

The first pic shows the Thermostatic Radiator Valve (TRV). There is a single arrow on the chrome body, pointing towards the radiator. So this should be the flow pipe. You can check this. It should get hotter before the pipe at the other end.

If the pipe at the other end gets hot first the TRV is on the wrong end. Modern TRVs can go on either end.

Hi - thanks again for the reply.

I've just taken the TRV off and the pin doesn't move up or down. However, if I push the pin in it makes the banging noise that I've mentioned. I take it that's a problem on it's own? Do I need to replace the valve?

Also, I think it's just a standard room stat - it's just a circular control at the top of the stairs.

Liam

 

[JohnD]

if I push the pin in it makes the banging noise

This happens if it is at the wrong end of the rad. The valve operates like a piston which is pushed into an aperture, if it is at the wrong end, the flowing water pushes it shut with a bang, like a door blowing shut in the wind. Sometimes you can reduce or cure it by turning the lockshied valve, at the other end of the rad, so it is almost closed (less than half a turn from shut) but this may reduce the rad temperature too much

 

[barnsleydyson]

Thanks - fingers crossed since I gave it a few taps with the hammer to 'persuade' it there's been no banging. Also, since I pushed it in the first couple of times it's not made a sound.

Here's hoping.....

Thanks for all your help everyone!

 

[barnsleydyson]

Think I spoke too soon - just before I went to bed last night the rad started making more of a hissing noise. When I turned the TRV down there was a slight bang but when I tightened the knurled knut the noise went away.

Do we think the TRV is at the wrong side then? Is there anyway to tell from the pictures I posted?

Also, how easy is it to switch it round?

Thanks again,
Liam