Hot water in central heating header tank

[x332race]

I have hot water in the header tank (F&E) to my vented central heating system....this has happened recently. As far as I can tell, the rads are getting hot.

Any ideas

 

[Stratman]

It's what's called 'pumping over'.

Try reducing the pump speed.

 

[stevieb15]

I have hot water in the header tank (F&E) to my vented central heating system....this has happened recently. As far as I can tell, the rads are getting hot.

Any ideas

or expansion from your hot water cylinder, thats what the Feed and Expansion tank is for

 

[x332race]

I know its an expansion tank and what it is for! However, the water in the tank is very hot and this should not be the case.....am trying a lower pump speed and slightly lower boiler temp.

Also have found that the tee-piece leading up to F&E tank is slightly magnetic which, being copper, it should not be...does this indicate a partial blockage...would this be contributing to the problem?

 

[stevieb15]

you could also look at the cylinder stat

 

[renault12ts]

Is the system making any unusual noises. Pumping over or kettling would be my guess too. Maybe the boiler stat is faulty.

 

[x332race]

Is the system making any unusual noises. Pumping over or kettling would be my guess too. Maybe the boiler stat is faulty.

No...seems to be running normally.

 

[renault12ts]

Have you easy access to the header tank. In other words can you tell where the heated water is entering. I suppose from the expansion pipe?

Had a thought. Your pump is working? Not just the upstairs rads getting hot?

 

[x332race]

There is only one pipe between the header tank and the system. There is no vent.

Also, despite having isolated the hot water cylinder and the cold water feed to the header tank, the water level has risen in the header about 2 inches overnight! Very strange.

 

[Charles Morgan]

I had a problem with hot water venting from my pressurised hot water cylinder - the internal cold water tubing had split leading hot water to pour out continuously from the tank out from the overflow, which caused a lot of water damage to my roof. I needed a new hot water cylinder, all because the original installer had not put on an expansion tank but had connected it to a pressurised cold water tank, meaning no expansion was possible.

 

[x332race]

I had a problem with hot water venting from my pressurised hot water cylinder - the internal cold water tubing had split leading hot water to pour out continuously from the tank out from the overflow, which caused a lot of water damage to my roof. I needed a new hot water cylinder, all because the original installer had not put on an expansion tank but had connected it to a pressurised cold water tank, meaning no expansion was possible.

That thought has crossed my mind but I (think) I have isolated the hot water cylinder by closing off the valves (mind you one of those is a motorised valve)