towel rail cold at the top after recent plumbing work

scottishkat

hopefully someone will be able to give me a hand. i had a plumber in a couple of weeks ago to move the radiator in my bedroom. since then the towel rail in the bathroom next door is always cold at the top. i have tried bleeding it (in fact i am bleeding it obsessively!!) and i always get air out but never enough to make the top of the towel rail warm and i dont get any water out of the valve no matter how long i bleed it for.
i have tried switching off the other radiators to increase the pressure but that didnt help and i dont have a combi boiler so topping up the system isnt an option. anyone got any ideas????
obviously i could just get the plumber back in but that cost more money......

Poppy9

Being a mere female I will probably be slated by pro men but here is what I do when I have knocking pipes etc. Have a look see if you have a bleed valve in your airing cupboard. It is a tall copper pipe with a small screw valve on the end. It should feel hot all the way to the top. If not slowly unscrew it and you should hear air hiss. Checking this regularly has cured the problem with my bathroom radiator. I too was always bleeding it because part of it was cold. I am on BG 3* cover so I can call them out for free. The gasman told me to bleed the bleed valve instead. Only problem I can't remember whether he said to do it when the system was off or on as one of them draws air into the system (oh I am such a girl)

fairenoughclough

This has always worked for me.

Turn all radiators to full on, run system for at least half an hour and then bleed highest radiator in the house.

Check pressure on system and if necessary top up system.

And finally repeat after another half an hour.

Altarf

scottishkat wrote:

i dont have a combi boiler so topping up the system isnt an option.

If you don't have a combi boiler, then there should be a header tank (probably in the loft) that will automatically top up the system.

It can sometimes take a few weeks for the air that gets trapped in the system to make its way out to the top of radiators.

If it continues beyond that, do you have any corrosion inhibitor in the system? If not, the gas that is accumulating in the towel rail may not be air, but the gas that is produced from the corrosion occurring.

Party_Animal

Is the top of the towel rail higher than the other rads?

scottishkat

Turn all radiators to full on, run system for at least half an hour and then bleed highest radiator in the house.

unfortunately i live in a flat so i am all on one level

party animal - yes, the top of my towel rail is higher, but this has never been a problem before. any ideas?
i am worried about the ammount of air that i can bleed from this, i can bleed it twince in half an hour and still get lots of air out the second time. could there be a leak in the system? i make sure and bleed them when the central heating is off so i am not pulling more air into the system.

Party_Animal

You could ckeck where he's moved the rad from and to, in partcular check the valves, the nuts onto the rads and the nuts onto the pipes. Is there a lot of head? between the top of your highest rad and your header tank. Somtimes systems are badly designed and take time to get rid of the air. You sometimes have to fit bleed points at a higher level than the rads but this is a last resort.

derrick

This might be obvious,but are both valves on towel rail open?

hutchie_3

You are probably aware of this but just in case,Never bleed radiators when central heating is on,you could get badly scalded

quoia

Bleed the radiator / towel rail with the PUMP TURNED OFF and let GRAVITY do the job!

Depending upon the exact location of the pump in the system it is possible (actually probable) that air is SUCKED INTO the radiator when you open the bleed nipple.

The reason for this is that the pump is normally fitted into the RETURN pipe and NOT the FLOW side of the boiler. It's done this way so that the pump runs cooler, pumping the "cool water" that has already done it's job having passed through the radiators and lost heat, and NOT the near boiling point water just after it leaves the boiler.

So, the pump USUALLY PULLS water out of the radiators and PUSHES it into the boiler. Depending upon the head of water and the volume and flow velocity the pump can handle, water levels in upstairs radiators can actually fall if you open a bleed nipple when the pump is running.

anskills

another scenario might be that the plumber may have upset the balancing off the radiators when moving that other one, try turning all the lockshield valves completely off (not the trv) and turn the towel rad one full on, then see if it heats up totally. i guess there could even be a blockage or he has not filled the system up correctly and bled off any air that entered after moving that radiator. id be calling him back whatever to sort the probelm anyway