My father had a similar problem in a residence, with a
temperature control mixing valve. He ended up buying two
check valves, and install them. End of problem.

Many stores, their sprayer has a squeeze valve, and it's
possible to leave hot and cold turned on at the mixing
faucet. The syptomatic thing is to have the restaurant put
check valves under their sink.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Limp Arbor" wrote in message
...
I work in a 4 story building with standard commercial
toilets and
urinals. For some reason when the valve for the spray arm
is left on
in the kitchen the toilets and urinals get supplied with hot
water.
Kitchen is on the 2nd floor and the warm toilets affect at a
minimum
floors 1 through 3. The building has circulator pumps in
the
basement.

Could this possibly be by design?

No this is not in WV. It is in NJ in a building less than
10 years
old.