Ok, I've not too much info on this one, but just found out that my sister has been having problems with the plumbing in an old house that she's just bought. I went around last night to size-up the problem and see what I can do to help her...
Quick description of what I've seen so far...
Central heating controller in Kitchen. Ground Floor Hot water cylinder in bathroom, enclosed in airing cupboard. 1st Floor Above HW cylinder, a feed tank (approx 600mm x 400mm x 400 mm) Cold feed into feed tank* Pipe from feed tank into bottom of cylinder External cylinder stat, set to pretty much highest temp.
- Cut, and the supply side capped.
The story starts the night that she moved in. She believed that the central heating was goosed ("the controller won't work" - ok, controller in kitchen, basic power switch found in the bathroom / tank cupboard - so I've now found how to get the controller and boiler back in operation). Because of the central heating malarky she decided to use the immersion heater, instead. Working the hours that she does, she leaves the heater on from late pm to late am.
In the morning, she found water dripping from the ceiling in the bathroom, into the walls and into the kitchen, below. At the time, the weather was dry - so the logical assumption is that this is related to the water supply.
She also finds water dripping from the pipework from the header tank, into the bathroom.
Calls an emergency plumber who, in retrospect, she didn't think knew what he was doing. He claimed that he couldn't work out what was going wrong, and as an emergency repair he cut and capped the cold water feed into the feed tank, then drained the hot water cylinder. He also claimed that hot water was getting into the feed tank.
Now, she's left with no hot water or central heating (not that she thought CH worked, anyway).
So, that's the situation that I was presented last night. Tonight I intend to remove the cap, insert an inline valve and restore the supply to the feed tank. Then, try to find the source of the leak.
Also, of note: plumbing appears fairly recent (still some shiny copper about), CH pump looks clean, guessing installation in the last 5-10 years. She intends to get the whole lot stripped out and new CH / HW systems installed, but needs to get by with a little HW for the time-being. Existing system = indirectly heated
Questions:
If the plumber is right, then why/how could the hot water in the cylinder feed into the feed tank above it - my only thoughts was a failed stat on the immersion heater leading to water boiling / expanding and feeding back into the feed tank.
What's going on in the roof?, okay, got an issue with the feed tank getting hot, but with hot-water (only by immersion heater), something is pumping / syphoning water into the roof (plenty of pipe work) but only when the immersion is on?!
Last one's wierd - there's a 3-port valve directing flow to either CH circuit or HW cylinder; but I found the actuator has been removed (still there, but dangling by the flex) - appears to have been unscrewed from the valve plate - screws missing. Looks to be deliberate, but I can't understand why. Any ideas?