16 • Residential Gas Water Heater Use and Care Guide
1974 requires the use of backflow
preventers and check valves to restrict
water from your home reentering
the public water system. Backflow
preventers are often installed in
water meters and may not be readily
visible. As a result, most all plumbing
systems today are now “closed,” and
almost all homes now need a Thermal
Expansion Tank.
A Thermal Expansion Tank is a
practical and inexpensive way to help
avoid damage to the water heater,
washing machine, dishwasher, ice
maker, and even toilet valves. If
your toilet occasionally runs for no
apparent reason (usually briefly at
night), that may be due to thermal
expansion increasing the water
pressure temporarily.
✓
Water Pipe and
Tank Leaks
Drain
Drain Pan
Drain Pan
Discharge Pipe
Figure 27 -
A metal drain pan piped to an
adequate drain can help protect flooring from
leaks and drips.
Leaks from plumbing pipes or from
the water heater itself can damage
property and could cause a fire risk.
•
Install an automatic leak detection
and shut-off device (available at
your local plumbing supplier). These
devices can detect water leaks and
can shut off the water heater’s wa
-
ter supply if a leak occurs.
•
Install a metal drain pan (available at
your local plumbing supplier) under
the water heater to catch conden-
sation or leaks from the piping
connections or tank. Most codes
require, and we recommend, install-
ing the water heater in a metal drain
pan that is piped to an adequate
drain. The drain pan must be at least
two inches wider than the diameter
of the water heater. Install the drain
pan so the water level would be
limited to a maximum depth of 1-¾”.
The pan must not restrict air flow to
the burner.
✓
Water Tempera
-
ture Regulation
Install Thermostatic Mixing Valves
to regulate the temperature of the
water supplied to each point-of-use
(for example, kitchen sink, bathroom
sink, bath, shower). Install and adjust
the mixing valve according to its
manufacturer’s instructions.
WARNING! Even if the water
heater’s thermostat is set to a
relatively low temperature, hot water
can scald. Install Thermostatic Mixing
Valves at each point-of-use to reduce
the risk of scalding (see Table 1).
MIX
Figure 28 - Thermostatic Mixing Valves installed
at each point-of-use can help avoid scalding.
BACKGROUND:
A Thermostatic Mixing
Valve, installed at each point-of-use,
mixes hot water from the water
heater with cold water to more
precisely regulate the temperature of
hot water supplied to fixtures. If you
are not sure if your plumbing system
is equipped with properly installed
and adjusted Thermostatic Mixing
Valves at each point where hot water
is used, contact a qualified person.
INS
TALLA
TION
INSTALLATION
