Plumbing problems - hot water to header tank

The most likely cause of the symptoms are a failed or non existent thermostat in the immersion heater. The unit would boil the cylinder, projecting hot water and steam into the loft tank via the open vent pipe usually violently causing splashing over and spillage into the loft and finding its way down from there. The loose actuator suggests there was a long term problem which had been bodged around and left for the future purchaser.

Your sisters actions should be IMHO

Inform purchase solicitor as even with caveat emptor there is an implied assurance the system will work (unless the contract enquiries answers "said" there were problems with the heating/hot water system. . Inform insurers who may be able to supply qualified assistance regarding the failed immersion thermostat and resulting water damage.

Inform the emergency plumber that he will be expected to (pay to) put right the non justified and non neccessary pipe cutting and blanking he did.

Your idea of putting a valve in the tank to cylinder pipe is sensible and IMHO should have been what the call out guy ought to have done. If he really didn't have a valve with him then simply tying up the ball valve and draining the head tank would have been sufficient to stop the leak situation until proper assistance could be called in (if he really couldn't tell where the problem lies - it sounds to me like he is a chancer making big bucks without any real knowledge!)

Hope this helps

You might understand if you give the tank its full name. It is a feed AND EXPANSION tank. When the cylinder starts off from cold and is then heated, the water expands really quite a lot. This hot water goes back up the feed pipe to the tank, where the level goes up. This water can often get quite warm. If someone has been stupid and put a check valve in the line, then it will go up the vent pipe instead, and will be very hot.

You need to get the cylinder cold, and watch the tank as the cylinder heats up to see if the hot water is coming up the feed pipe or the vent pipe.

The tank will get warmest and the level rise the highest when the cylinder has started off stone cold.

It was broken and they couldn't be bothered to fix it.

Christian.

The 600 x 400 x 400mm. header tank also seems a little small for the job even if it is just serving the Hot Water cylinder. Where is the main cold water storage tank?

Chris.

Ok, quick update...

Hmmm, the header tank is a little small, but then so is the cylinder (well, quite a narrow diameter, guessing 400mm dia, under the insulation). All designed to fit in a small cupboard, rather than, perhaps, function.

Fitted inline valve to feed to tank and restored the supply; tank started filling. Went to attic to check on situation up there - bone dry, so I'm thinking water on ceiling in bathroom is condensate, nothing more (have to discuss this later with sister who was at work whilst all this was going on).

Got back to bathroom to find water dripping from the plywood sheet that the feed tank is sat on, onto the pipework and then generally splashing about. Closed the valve and started draining tank via bath tap. As the water level subsided the leak got perceptably less, although the natural hystersis in the tank / spongy plywood makes life difficult to diagnose.

So, with both torches dead, and 3 hours later, got bored and came home to think.

Think the next best thing to try, I think, is to fill the feed tank, inch by inch, with 10 minutes between each fill to find where in the tank the leak starts. I've tried to search for an obvious leak, both externally and by running my hand along the inside of the feed tank, but there's nothing obvious (well, hard to tell when you have your cheek pressed against a 10ft ceiling, hanging off a step-ladder)

Which leads me to...

Anyone heard of tanks splitting?, I don't think it's a problem with pipes/unions, since the leak starts rather higher than the outlet (which is dry, anyway), and somewhere lower than the feed pipe / overflow pipe.

Is that 600 x 400 x 400 header tank made of plastic/poly whatever? That may have cracked due to ice in the past and is now supple enough to stay shut until head of water is enough to open the crack. Does this header have an overflow outlet?

Chris.

That's my big fear, and yes it is a black plastic / poly / slightly supple material (same as every other feed tank I've seen in the last 10 years).

It does have an overflow outlet, but this is higher than the tide-mark on the inside of the tank for the water level.

Could be a right ball-ache to replace, since it's basically built into the space for the cupboard, and the three sides of the cupboard walls are all brick. Can't get to either side or rear of it; did plan to drain it completely and try to raise is a couple of mm and with help of torch try to see where the water leaks from the base of it onto the plywood plinth.

I'm guessing that if this is a pinhole failure (unlikely, I know), I can possibly patch this from the inside; if it's a split due to pressure then this is a new tank job.

Thanks for responding; I'm back there tomorrow to have another look in cold light of day, and with my sister present.

Hot water in your header tank is not good.......there are a number o causes..OVERHEATING is the main one....Also poor piping....Pump spee too high.....if your header tank is metal id change it to plastic i you suspect a leak....

the actuator should not be separated from the valve...a sticking en switch in the actuator could cause PUMPING OVER of hot water to you header or overflow pipe....

Hot water in your header will lead to blockages and inefficiances i years to come from your ch system....hot water out of your system i replaced with fresh cold water loaded with AIR...this air cause corrosion and you usually see mucky rusty water in the heade

-- gastec

Did you actually READ the original post? The tank in question is the cold header for the HW system - *not* the F&E tank for the primary circulation system. The problem occurred when the immersion heater was on but the boiler/pump were *not* on. So forget about pump speed and pumping over!