Cold radiators and overflowing header tank

[diytry]

Guys,

Wonder if you might be able to offer me some advice?

I had a leaking valve on a radiator connected to the pipework leading to my hot water cylinder. The radiator is situated in the attic and is the highest radiator in all the system.

I drained down the system enough (or so I thought) to replace the valve. During the draining process I heard a gurgling noise from the kitchen radiator so assumed that the system was more then drained below the attic level.

As I removed the valve there was still plenty of water in the radiator which I manually drained. I replaced the valve and refilled the system.

After bleeding the radiators I switched the boiler on to test. I have found that the attic radiator and the cylinder flow and return pipework heat up as it should, however at first I had no heat to any of the other radiators.

I left it over night and tried today. I have found that most are now warming however a couple don't warm up at all. Furthermore I have water pouring out of the overflow from the header tank (when the boiler is on). I'm assuming that there may be a blockage, but am unsure as how to deal with the overflow and cold radiator.

If it helps the system has no pump, or room stat, it does have a programmer allowing the choice of either hot water, heating or both. It is an old Thorn floor standing boiler. I'm assuming that this somehow works on gravity.

Any advice would be greatly appreciated.

Yours

Johnny

 

[Nige F]

Overflow from header tank ...pipe to the outside of building. OR vent over top of tank running when boiler switched on. No pump not hidden somewhere....Size of pipes up/down to radiators Thanks,

 

[diytry]

Thanks for the reply Nige,

It is the overflow that is flowing. I can't see the vent pipe as the header tank is hidden away in a really small overhead cupboard in the eves above the attic.

The pipework is 22mm (maybe 3/4"), as its back bone with all radiators being fed from 15mm (or 1/2") copper. It's ages old and when I drained some of the system down found plently of sludgey water coming out.

My one thought was to connect the mains inlet supply to the CH pipework and literally push out the blockage or air (if that is what it is). However I'm scared of casuing damage to the boiler or the system in general.

J

 

[Nige F]

Overflow...change the ballvalve...ok to fill from the mains, if you have a double check valve on the tap feed or the filling hose...stops backflow of the cruddy water into the drinking water...costs a couple of quid. If you`ve got an outside/hose tap there should be a check fitted to the supply. Does sound like a gravity setup Does the" backbone "rise right through the building

 

[billington]

This system is in need for an upgrade, your fuel bills must be sky high.Find your self a nice corgi man to give you an estimate for a fully pumped system complying to part L 1