Feed and Expansion Tank

[Charley]

Your help would be apprecaited. My feed and expansion tank keeps filling and overflows into the main water tank. What are the potential problems and remedies. I have replaced the main valve cock on the water tank. I am not sure what is causing this to happen, but what can I expect on cost to rectify. I was led to believe it may be a faulty coil in the hot water cylinder. Is this correct, or couyld it be another problem.

Charley

 

[chrishutt]

Not likely to be a leaking coil since your CH FE tank is higher than your DHW cold feed tank. Have you checked for discharges from the vent pipe (pumping over)?

 

[Charley]

Chris Hutt

Thanks Chris. What do I have to do in connection to the vent pipe if it is that to stop it from filling. Whats the remedy.

 

[weareleeds]

If it is pumping over you could have a blockage around the cold feed area which will involve clearing but more important it to cleanse the system to prevent further problems. If your boiler allows it may be possible to seal system but without any more details a proper diagnosis is impossible

 

[Charley]

It is an indirect system. The F & E tanks is above the cold water tank. It is a traditional British domestic hot water supply system, in which water is heated and stored for use, is based on cold water feed from a storage cistern to a heated cylinder that is vented to the atmosphere. My bolier is an ideal standard W2000, approx 16 years old, but serviced annually.

 

[ChrisR]

I can't make sense of what you're saying is happening.

expansion tank keeps filling and overflows into the main water tank

So the overflow from the heating f/e tank goes into the main cold water tank??? Shift it so it goes outside!!

Don't confuse an Overflow with a Vent pipe. Vent is the the one (one for each tank) which comes up over the top.

 

[Charley]

The F & E tank is filling up almost to the top, where the overflow pipe is into the cold water tank. The cold water tank has a overflow as norm that goes outside. I am concerned why the F&E tank keeps filling almost to the top, so there must be a reason. The float valve in the F&E is working, but is almost totally submerged. I drained the F&E tank yesterday, but it filled up within a couple of hours. Even if i directed the F&E overflow to the outside, it will still constantly drip, so need full details in how to stop it. You help is greatly apprecaited. What tests can I conduct.

 

[JohnD]

First, you want to make sure the ballcock/float valve in the F&E isn't dripping. If it has a tap in the supply, turn that off. As these valves are quite cheap, you could do worse than just take off the old and fit a new.

Measure the old one as some F&E tanks are quite short so have a shorter arm than some new ones.

From your description, this seems to be the most likely cause. I would expect the water in the F&E to be quite clean and clear looking, though there may be old sediment at the bottom.

Also, look at how you might re-route the overflow so that it discharges outside the house. Water from the radiators is going to taintthe water that you was and clean your teeth in. It probably contains ant-corrosion chemicals.

When you have fixed the presenting problem, you will need to clean out the radiator circuit and refill with corrosion inhibitor, as the old will probably have been washed out and the fresh water will encourage the radiators to rust from the inside.