overflow pipe

iglimpse

Overflow pipe has been dripping. thanks to all the excellent advice on here, replaced the ballcock and arm in the tank :T

But to my horror, problem continues even though the water level is below where this pipe emerges. Seems to be coming out of smaller overflow pipe. After all that effort :mad:

Anybody got any further clues. Typical semi. Central heating all OK (boiler 25 yrs old though).

thescouselander

Did you replace the ballcock in the correct tank? It could be the small header tank for the central heating that is overflowing and not the main cold water tank.

EliteHeat

The first thing to do is to identify which tank is overflowing. You probably have two; one cold water tank and one header tank.

Next, you need to work out under what circumstances the overflow pipe is running.

Assuming that you have replaced the cold water tank valve, then it is likely that the problem originates from the smaller header tank.

The overflow can be caused by the following faults:-

1) Simple valve failure or adjustment required. With the heating system off, the water should only be 2-3” above the bottom of the tank. If the water level is too high then the overflow pipe will start to run when the boiler is on, due to the expanded volume of heated water.

2) Water entering the tank via the open vent. This is called ‘pumping over’ and is normally caused by a heavily sludged up system and will require specialist treatment. This will happen only when the boiler is running.

3) Water entering the tank via the cold feed to the heating system. This is caused when the hot water cylinders heating coil is pinholed and the header tank is lower than the cold water tank. The only solution here is to fit a new HWC – a very common problem. The overflow will run regardless of whether the boiler is running or not.

iglimpse

Cheers. It was the other tank. Job done. How much do you think a plumber would have charged for that ?? Cost me £7. I just love this site

EliteHeat

iglimpse wrote: »

Cheers. It was the other tank. Job done. How much do you think a plumber would have charged for that ?? Cost me £7. I just love this site

Charge would have been a standard callout fee plus parts. So you've saved yourself £40-£70'ish :j