Supply tank overflowing and radiators come with hot water on only

[Andy123]

For about a year now the radiators have been coming on with the hot water switch only on whereby i have got round this by turning the rads of but the past few weeks the small feed and overflow tank in the loft is filling up with hot water up from the airing cuboard from the feed pipe which is really hot all the way up to the tank, its not coming from the overflow pipe bent over the top of the tank but from the feed pipe at the bottom of the tank causing it to overflow onto my conservatory roof.

The system is really old about 20 years or so.

I thought it may be coil in the cylinder is broke as this would fit both symtoms but not sure.

Any thoughts appreciated.

 

[SimonG]

Its not the cylinder. Try looking at your 2 port / 3 port valve.

 

[diamondgas]

Sorry to disagree SimonG, I believe the perp is right ... Sounds like you have a cylinder coil that has become pourus.... Most definitive way to find out is isolate the mains feed to the ball valve of the F&E header tank. If it continues to fill and overflow there's usually only one other place it can get it's water from; the domestic header!

 

[SimonG]

Sorry to disagree SimonG, I believe the perp is right ... Sounds like you have a cylinder coil that has become pourus.... Most definitive way to find out is isolate the mains feed to the ball valve of the F&E header tank. If it continues to fill and overflow there's usually only one other place it can get it's water from; the domestic header!

I disagree with the cylinder . Had a problem for a year with 2 port / 3 port valve, so rather than getting fixed properly, shut down rads. Expansion now probably blocked and expanding up cold feed.

Really need a few more details and maybe some pics or failing that a call to aa plumber to have a look.

Be interesting to see what it was

 

[diamondgas]

SimonG: sounds like your are talking about the extreme rather than the norm yeh? Possible I'd agree but would go down the route I suggest first! Isolate the F&E no heating on at the mo ...

 

[SimonG]

Not really just that the only mention of an issue is with hot water. Would have been tempted down the cylinder road if it was happening cold as well. But no reason why op can't rule that out, I just believe it's a follow on to not getting the original problem sorted.

 

[Billy Bob Bob]

call a AA plumber to take a look that will be handy he can hit the cwst with a hammer stick some jump leads on the motorised valve and tow the boiler away

 

[Andy123]

Thanks for the replies, the reason i thought it was a broken coil in the cylinder is the large hot water supply tank in the loft has a much higher head of water than the small tank and once the small tank reaches a certain level to overflow, it does not seem to increase after that. I know very little about central heating/plumbing though as i come from an engineering background. Will have to try that test cheers.

 

[diamondgas]

call a AA plumber to take a look that will be handy he can hit the cwst with a hammer stick some jump leads on the motorised valve and tow the boiler away

AA as in Alcoholics Anonymous yeh? ... lol

 

[diamondgas]

Thanks for the replies, the reason i thought it was a broken coil in the cylinder is the large hot water supply tank in the loft has a much higher head of water than the small tank and once the small tank reaches a certain level to overflow, it does not seem to increase after that. I know very little about central heating/plumbing though as i come from an engineering background. Will have to try that test cheers.

Let us know what happens Andy please