I am Facilities Mgr. of an school in a 90 year old building...it once
was a hotel.
Recently we are getting hot water coming out of the cold water tap in
various parts of the building...it starts really hot...within a minute
or two it starts to cool off...
very strange...so far as I know nobody has fooled with any valves or
it seems to happen any time of day.
any body got any ideas?
A couple of possible reasons:
1) Thermal expansion in a water heater tank "pushes" hot water
back out the Cold inlet, where it then gets into the Cold main.
2) Unintended cross-connection between Cold and Hot supply lines.
Often happens when a single-handle faucet cartridge wears out
(Moen is a frequent culprit).
Washing machine valves will sometimes do this too.
In an old hotel, there may have been numerous connections between
Cold and Hot.
Start with the water heater(s). Feel the cold inlet pipe when there
is no water useage and see if hot water is migrating out.
If not there, you'll really have to play detective...
Had that problem with my house in Arizona. Water pipes are buried under the
slab there and a hot water pipe broke under the slab in the bathroom. The
bath sinks would run hot water until the water that had been heated by the
hot water in the soil was run out the faucet. This happened twice in two
years in two different places. Assuming you have a water meter, try
shutting off all water faucets except for the main valve and check the meter
to see if water is still passing through the meter. Of course if you have a
basement, this couldn't be the problem.
Look in the yellow pages for "Drain Cleaning". Roto-Router, Rooterman, etc.
They will come, clean the drain and will be out of there in under 2 hours.
It cost me $75 and didn't damage my pipes. My previous tries with
coathangers, augers, snakes and chemicals just didn't do anything except
cost me time.
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