"PipeDown" wrote in message
ink.net...
The other faucets probably didn't show signs of being overpressured
because the aerators or built in flow limiters were working on those sinks
which apparently they were not in the kitchen sink

The expansion tank may or may not be needed. If you already have a few
water hammer arrestors and the hot pipe volume is not too great, you can
get by without. Think of the bladder (expansion tank) as a very large
water hammer arrestor installed at the supply end of the pipe instead of
at the delivery end. Both of these devices allow the water pressure to be
absorbed in a flexible component instead of stressing the otherwise rigid
walls of the pipe network.

If there is a check valve on the cold supply going into the hot tank (or
the new pressure regulator) such that when the hot water expands the
additional volume has no where to back out, then you will see a short shot
of pressure whan you turn on the tap and then quickly return to normal.


All correct answers.

New code states that all homes are to have a back flow preventer. So, if the
water comes in at lets say 45 degrees and then heats up to 110 in the HWTank
its going to expand. Your pressure will rise due to this. If the kitchen
sink does not have an aerator it will blow out fast then slow down. Also,
faucets in bathrooms actually help control the amount of GPMs allowed, its
an energy and conservation design into the facet, which kitchens do not
have. Every showerheads flow is restricted by an orifice much like that in
aerators.

Now, with a pressure reducer and back flow preventer you must have an
expansion tank or you can damage both the reducer and backflow valve. IF
your meter has a backflow preventer/check valve in it and you do not have a
pressure expansion tank you will be charged for a new water meter by your
utility! Also, it is now code that you must have a backflow preventer, some
areas are starting to demand proof that they are tested and work by a
licensed back flow tester, some every year others every third year. This has
been the law for commercial/industrial for some time and it is being
implimented for the residential market.

Do what the plumber says and stand there BEFORE he does the work and show
him what is happening. If it still does it afterwords tell him to take it
off and hit the road. He should have gauges that can show you the actual
pressure before and during the water being turned on.