Hot water in cold water storage tank

[Teggs]

Guys,

I wonder if any of you could suggest the reasons my cold water storage tank is filling with hot water. I first noticed this when my shower stopped getting cold. At first I thought it was the shower pump but on further investigation I noticed that the water in the tank was very warm, almost hot.

Any help would be appreciated,

Terry

 

[Onetap]

What sort of hot water system is it? An open vented cylinder? If so, then possibly/probably the end of the open vent pipe is dipping into the water in the tank, allowing hot water to rise by convection up the open vent, being replaced by cold water going down the cold feed.

If it's heated by an electric immersion heater, I'd suggest you turn it off until the problem has been rectified since it could be a defective thermostat, which is potentially more dangerous.

 

[mbga9pgf]

http://www.metro.co.uk/news/82750-3-5m-homes-may-have-fault-that-killed-baby

Get it checked ASAP.

 

[Teggs]

Sorry should have said it is an open vented system, heated indirectly. Although there is an immersion heater this is turned off (I've tested for voltage).

I was assuming that this would be steam venting into the tank but what would cause it?

Thanks for your replies so far.

Terry

 

[seco services]

can be mains cold back filling the hot supply.

 

[dennyboy]

can be mains cold back filling the hot supply.

so could a bath mixer tap cause that?

 

[Teggs]

Funnilyenough I isolated both the basin and shower which utilise the tank and pump that they are also joined to, however I was not starting with a cold tank of water so that may well be it. I'll keep you posted.

Terry

 

[seco services]

can be mains cold back filling the hot supply.

so could a bath mixer tap cause that?

bath, basin, kitchen, shower can all cause crossover of water supplies if
the cold is mains hot gravity.

 

[Onetap]

can be mains cold back filling the hot supply.

Could be, but the tank may also over-fill or overflow as well. Any mixer taps with mains cold connected? A kitchen mixer with a open vented HW system should mix at the spout, not in the body of the tap; you'd be able to feel the hot pipe and tell if the cold water goes back up it when the tap is in use.

Getting a hand on the open vent and cold feed should tell you which one the hot water is using to get into the tank.