Central heating woes.

I found that if you make sure that the thermostat is calling for heat, remove the thermostatic head and using a teaspoon as a thumb shield press down hard on the pin, repeatedly until after several (dozen) presses you will feel the pin spring up and start to hear water flow. (I suppose it could also just be an airlock so if you close all radiators except the cold one, it may push it through and you can bleed the air out)

How does 'air' get into radiators - the 'air' that comes out is a flammable gas and will ignite. In effect it is your system that will be coroding. Once your system is working, it will be time to put some Fernox or similar product in before it is way too late.

Yep,

Hydrogen to be exact. Water (H2O) + Iron (Fe) = Rust (Fe2O3) leaving Hydrogen (H2).

Robert G8RPI.

Bleed some water out of the radiators into an eggcup.

Fingers in the eggcup, it should feel 'soapy' or else you will have big, big problems.

If you haven't already done this, close the taps/valves on your cold radiator, then open them fully.

This is where a blockage will occur, if there is any debris in the system.

If that's successful, then you can adjust your taps/valves to suit your heat requirements.

Good luck,

Bear..

A couple of things which I have experienced which might help. I was having a problem of pressure loss a couple of years ago and eventually found it to be a very small leak on the bottom thread of one of the radiators. To fix, this would normally mean a drain down and removal of the radiator but I solved it by getting a bottle of sealer from ScrewFix. It is designed for central heating systems and does not damage the other moving parts . This solved the problem and I have not had any trouble since.

Usually at the end of the Summer, I remove all the radiator thermostat valve heads and using a pair of pliers and spray lube work the pin back and fore to make sure they don't freeze up during the time the central heating is off. If the thermostat top is carefully removed, it can be replaced without loss of the settings.

This lockdown has caused quite a lot of problems. About 4 years ago, I had new triple glazed windows fitted and about two weeks ago, there was a loud bang when one of them failed. The curious thing is that the middle pane is broken and completely crazed where as both the outer panes are untouched. because of lockdown, we will have to wait for a repair. Luckily the window is safe and functional so I will have to wait for the report.

Thanks for further replies.

I tried Jim Young's suggestion of closing off all rads but the cold one, and opening that fully at both ends. Result! Thanks Jim.

Strangely the boiler seems to have stopped dripping now and the pressure is holding up. Perhaps some crud has moved and stopped up the leak. I'll have look inside the boiler and see if there is any obvious witness to the source of the leak, but unless it starts leaking again I'll leave it be until BG can get round.

Robin.