F+E tank feed question

[jack95noon]

Moved into an old house that has a vented gravity fed system (cold water tank and feed + expansion tank in the attic). I need to replace all ceased gate valves which is all of them...

The feed pipe from the F+E tank to the oil boiler/radiators has a gate valve in the open position at the moment.

I would have thought this should be in the closed position unless the system needed to be topped up?

Should it be in the closed or the open position? Cant find anything online for this?

 

[Ric2013]

On the cold feed from the bottom of the cistern. Should be open, and some say shouldn't even be a valve. The water needs to expand up the cold feed when heated and run back down it when it contracts with cooling down after. (If the valve is shut water will use the vent pipe for expansion, but that's not really how it's designed to work).

 

[John.g]

As above, but could and should be IMO a isol valve on the makeup to the F&E tank which I keep shut and open very occasionally to check for system leaks, similar to the top up flexible hose in a sealed system.

 

[Ric2013]

As above, but could and should be IMO a isol valve on the makeup to the F&E tank which I keep shut and open very occasionally to check for system leaks, similar to the top up flexible hose in a sealed system.

On the mains pressure feed to the ballcock (float operated valve)? Absolutely. Actually, if you are prepared to use it in the way you describe, you need neither an overflow nor a ballcock. (Most people won't bother, however, and a conventional setup will suit them better.)

 

[John.g]

The makeup isolating valve with the conventional ballcocked F&E tank is very useful because if there has been any leakage then its easy to estimate the leakage rate, I am allways a bit surprised that my system never and I mean never takes even a drop of water between the ~ 1 to 2 month check intervals.