Avoid On-Off Valves on Shower Heads
Some high-efficiency shower heads include an onoff
valve. Figure 4 shows an example.
In principle, this valve avoids the need to adjust the
main hot and cold water valves. Once the main valves
are set properly, the water is simply turned off at the
shower head.
Don’t use this type of shower head. In reality, it
probably does not speed the process of getting the
desired water temperature in the shower. The stagnant
water must still clear out of the hot water supply line,
and this takes longer if the user does not open the hot
water valve to clear the line quickly.
Furthermore, this type of shower head may cause a
continuous leak. If the main valves are left open with
the shower head valve closed, the water line that
connects the valves to the shower head is kept under
pressure. This causes the valves to leak if they have
leaky packings. If the shower is used with a tub, a
diverter valve is installed, and this may leak. The valve
in the shower head is a crude device that eventually starts
leaking itself, so it has to be abandoned anyhow.