View the thread, titled "hot water really hot" which is posted in Plumbing Advice for Any Other Country on UK Plumbers Forums.

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peterrawlings

I have recently discovered that my hot water has got extremely hot so much that its you arre unable to put your hands under the tap when its running. I checked the thermostat and it was set at 50 so i turned it down still no difference so i changed the tank thermostat still no difference. I switched off the hot water switch on the control box and found that the water was still heating up!!!. I have a normal vented system with an Ideal Classic boiler. However I was in the loft yesterday and noticed that the open vent pipe that vents into the central heating header tank was dribbling water when the pump was running. The hot water tank is heated only by the boiler and has a motorised valve on the pipe leading to the tank. I hear that operated when I turn the thermostat on the tank up and when I switch on/off the hot water on the control panel. Any ideas what the problem is. I do have central heating insurance with E-ON my electric and gas supplier.
 
If you have insurance why are you asking us? Whatever they do you will get it for free. Get them to sort out the pump-over (fault you described at the header tank) at the same time. Otherwise your system will sludge up in double quick time.
 
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I only wanted to know what the problem was, I have been reading the thread on the forum about British Gas service engineers ripping people off. If I knew the problem it would give me some idea so when the engineer arrives (next 5 days as its not classed as an emrergency) if he tries to say its not covered by the insurance I will be armed with some sort of info. SORRY TO HAVE BOTHERED YOU GRAHAMEP. I thought this was a friendly type of forum.
 
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Pete, there is a possibility that the coil (heat exchanger) inside your Hot Water Storage Cylinder has failed, not certain though, because if it had, I would expect your vent pipe to the cold water storage tank to be running (because of the extra water being pushed into the hot tank) and as a result your overflow from the CWS would also be running. Go and have another look and see if any of that is occurring. If I'm right, you will need a new Hot Water cylinder. In which case good job you're insured.

As you have a separate expansion tank and a CWS tank it is reasonable to assume that you have a standard "indirect" cylinder and not a primatic one.
 
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>Hot Water Storage Cylinder has failed, not certain though, because if it had, I would expect your vent pipe to the cold water storage tank to be running.

if your your f/e tank & cws tank are positioned right f/e lower than cws a failed coil will result in the cws tank emptying and your f/e tank filling and not filling through the vent pipe but the cold water feed at the base of the f/e (water takes the shortest route)

> I switched off the hot water switch on the control box and found that the water was still heating up.

more like a bypassing motorised valve.

> However I was in the loft yesterday and noticed that the open vent pipe that vents into the central heating header tank was dribbling water when the pump was running.

thats useally more to do with a blockage or pump speed to high.


> I hear that operated when I turn the thermostat on the tank up and when I switch on/off the hot water on the control panel.

if you have heating off at programmer and operate the hw on/off at the stat or programmer you shouldn't hear nothing from the mot valve as it will be in relaxed position for hw. (heating closed hw open) and resistance on the lever.

the motor in a 3 port will only operate if heating called for.


have you checked for a bypassing 3 port valve. system cool heating only on to pipe to the cylinder should remain cool.
 
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Thanks Sonray the pipe that enters the cylylinder from the motorised valve is hot all the time so I suspect motorised valve problem. Best call out the experts. You dont work Canvey island area?
 
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