Incoming water main hot

[nutler]

Hi all,
Here's an odd one hopefully someone can help with.
I have a customer that has hot steamy water coming from their kitchen cold tap. The tap is fed directly from the incoming main which enters the house under her back door. The kitchen floor is hot along the run of the water main (about 0.5m) also the outside steps upto the the back door and about 3m of the driveway again along the pipe run. The pipe is galvanized steel from under the sink along to the 3m point in the driveway from which plastic takes over out into the street.
If you run the cold tap for about 2mins the water goes cold, wait 10mins and run again and you have 2mins of hot water again.There are no other pipes/cables anywhere near the run of the main. This occurs even when the electricity is turned off to the property to rule out a fault.
Any ideas ?

 

[Mike Jackson]

Backflow from a neighbouring property with an unvented hot water cylinder?

 

[Anton]

I'd be getting that checked out with the electricity suppliers asap. There could be a mains supply laid underground too close to the water mains or to a gas mains supply pipe.
I have seen a gas supply pipe on fire underground caused by proximity to an electrical supply cable.

 

[bright spark]

How is the neighbours water. If it's the same, then the council may have a booster pump located nearby gone faulty and running continuously. The heat off the pump would heat the mains. Saw that happen before in an apartment block with everyone getting hot mains water.
if it's not that the. Would be an idea to have electrical supplier check area just to rule it out.

mad things happen. Once a customer that owned a creche told me they had hot water coming out of toilet when they flushed it. It ended up water supply came through service duct under floor. There was a leak on pipe in duct about 6 inches of water gathered. When heat came on it heated water like a cylinder. Water going to cistern was heated up. Flush the jax and hot water out.
Mine for the books

 

[AWheating]

Had hot water from a water harvesting tank once, faulty pump was overheating and warming the water like an immersion heater.

 

[nutler]

Thanks for the quick replies guys.
Have had electricity board out to check their end and they say all is fine.
They did find a faulty appliance in the house that put a small current down to earth which includes the water main. Thats now fixed but hot water continues to run. No sign of heat at the water meter in the street, ruling out neighbours property and pumping station.
Is it possible that the small current down to earth has set of a chemical reaction or electrolysis between the galvanized pipe and the wet ground ?

 

[Chalked]

Thanks for the quick replies guys.
Have had electricity board out to check their end and they say all is fine.
They did find a faulty appliance in the house that put a small current down to earth which includes the water main. Thats now fixed but hot water continues to run. No sign of heat at the water meter in the street, ruling out neighbours property and pumping station.
Is it possible that the small current down to earth has set of a chemical reaction or electrolysis between the galvanized pipe and the wet ground ?

Impossible.
what system is in the house? Pressurised? Tanks in the loft? Shower pumps?

 

[Chalked]

Is it a single lever sink mixer?
When all pipes are cold under the sink, run the cold only and see if the hot feed becomes hot? Might be simple as a faulty tap!

 

[Anton]

Thanks for the quick replies guys.
Have had electricity board out to check their end and they say all is fine.
They did find a faulty appliance in the house that put a small current down to earth which includes the water main. Thats now fixed but hot water continues to run. No sign of heat at the water meter in the street, ruling out neighbours property and pumping station.
Is it possible that the small current down to earth has set of a chemical reaction or electrolysis between the galvanized pipe and the wet ground ?

When you find out what's causing the hot water, make sure you let us know on here.

 

[nutler]

System update.
It is an open vented system with indirect cylinder (no immersion wired) heated from gas wall hung boiler, external circulation pump fitted near cylinder and 3 port valve. There are no other pumps in the property(no showers).
Pillar taps at kitchen sink and throughout the house. The cold is as it should be in the rest of the house and loft tank.
Sooooo bizarre !