Still trying to fix the overflow problem (see Thurs 27 Jan)

[harris48]

I have checked the house and there are 4 points where the cold water could mix with the domestic hot water. I have placed a check valve on pipe that feeds the hot for the sink and wshing machine and also been able to isolate the hot water for the mixer tap on the bathroom basin. The problem still continues and my last port of call is the mixer shower - the hot and cold pipes for this are hidden in the wall so diffcult to put check valves on these. Would it cause any problems if i put a check valve on the cold feed to the cylinder from the cold water storage tank and also on the hot pipe from the cylinder (below the tee for the vent). If not any other suggestions please.

 

[brumylad]

don't put check valves at either point, it would be dangerous. When the heated water in the copper cylinder expands it does so by moving up the cold feed pipe.

remind me, which cistern is overflowing, CH header tank or cold water storage?

 

[kevplumb]

don't put check valves at either point, it would be dangerous. When the heated water in the copper cylinder expands it does so by moving up the cold feed pipe.

remind me, which cistern is overflowing, CH header tank or cold water storage?

whats the vent for then

 

[harris48]

The cold water is the one that is overflowing. Is it best to put check valves as close to the mixer shower as possible.

 

[ChrisR]

whats the vent for then

GAS/WATER VAPOUR/AIR!

remind me, which cistern is overflowing, CH header tank or cold water storage?

remind me too please!

 

[felix]

The shower is the prime suspect. Check this by closing the main stopcock. If only hot water comes out of the shower it means that some plonker has taken its cold supply off the mains instead of from the cold tank. If this proves to be the case then replumb it properly. You really don't want to be in the shower when your mains water supply suddenly goes off!