DIY Doctor

Very hot water in my expansion tank - Help !

Postby 80Sprint » Tue Jun 10, 2008 7:58 pm

I have very hot water in my expansion tank and it is overflowing onto the roof. There are 2 overflows going into the tank. One is dry the other has a steady flow of water. The pipe runs back down to a bend where it joins another larger pipe, this has a tap higher up, and the large pipe runs downstairs where it goes off in 2 directions. One direction has a vale on it.

Any idea's where i should start. I have heard the tank could collapse !

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Simply Build It

Postby plumbbob » Wed Jun 11, 2008 8:39 am

Certainly, there is a risk of the tank failing suddenly as they are not designed to hold hot water over a long period of time.

It would be wise to switch of the hot water/heating until the problem is resolved.

Unfortunately, it is difficult to offer serious advice, as you have not really given any details about what type of system you have and it is not wise to offer advice based on assumptions and guesswork.

Unless you have a certain amount of understanding about hot water systems, it would be advisable, considering the risks involved, to find someone with experience who can rectify the fault and examine the tank to ensure it has not already been damaged.
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Postby Skids » Thu Jun 12, 2008 7:28 pm

Hi 80Sprint

Is the Hot Water Cylinder overheating?

Dose the boiler shut down when the HWC reaches temperature?

You might start looking at the thermostat on the side of the HWC? which should tell the boiler to shut down.

If the HWC is being heated by a electric immersion heater, check the thermostat is cutting out?

Bit more info on the system would help?

All the best.


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