Central Heating Header Tank filling up with Hot water - help

[ctaylor]

Chaps

I know this is probably a common problem and I've searched and got conflicting diagnosis.

anyway here goes.

The small Heating header tank was over flowing. I emptied and Tied the ball cock up in the air to stop it filling. Drained it to just above the bottom Pipe. Checked it a couple of days later and it was nearing the overflow again and Hot. I noticed when the Water / Heating is on ( simple timer so both on at the same time) the larger Copper pipe which drops in from the top is trickling. when heating/water off its dry.

Believe its called the open vent (22mm copper)

Any Ideas?

I have a new Cylinder Thermostat to put on just incase thats is the issue. although not sure on wiring. old one is C , NO, NC. New one is C, 1 ,2

Thansk in advance

 

[JBPHS]

What speed is the pump set at?

James.

 

[stardanny]

You say you tied up ballvalve so it's not filling up, and lower water level to just above bottom connector.

Hmm, switch off heating and hot water, let it cool down and don't do anything till morning and check if overflow is running outside. Let us know.

Could be cylinder coil pinhole.

Daniel.

 

[ctaylor]

Cheers Guys

I changed the pump speed to 2 yesterday after reading up on the subject. it was on 3 but has been since qwe moved in 4 years ago.

It takes a week or two to start coming out of the overflow. I dropped the level a week ago say Saturday. Then went away for a week. checked it and it was pretty close to the overflow but not actually peeing out but not more than 1cm below the overflow pipe.

The water is fairly hot in the tank aswell.

Ballcock still tied up.

 

[ctaylor]

Sorry chaps not manage to turn off the heating and water yet been away with work. I do know its filling the header tank from the Vent pipe as I drained it down to the level last night and stuck a 2 ltr coke bottle under the vent pipe and it was full 24 hours later as was the header tank. not flowing out of the over flow but it just about gets to that level if you leave it long enough.

If I drop the level in the header tank again and turn Heating and water off and wait 24 hours and see if it fills up again? That will hopefuly point it in the right direction?

One other point I have noticed is the boiler in the garage never needs turning up to more than 1 or 2 on the dial even in winter at position 1 the rads are all hot. its always been like it.

Thanks again.

 

[twgas]

Before draining more water from system you need to allow it to cool, then check the water level.
The most common cause of pumping over (water discharging from open vent) is a restriction in the pipework where the feed and vent join system or incorrect pipe configuration.