A.O. Smith ProMax GPDX-50, Instruction Manual

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12
THERMAL EXPANSION
As water is heated, it expands (thermal expansion). In a closed
system the volume of water will grow. As the volume of water grows
there will be a corresponding increase in water pressure due to
thermal expansion. Thermal expansion can cause premature tank
failure (leakage). This type of failure is not covered under the limited
warranty. Thermal expansion can also cause intermittent temperature-
pressure relief valve operation: water discharged from the valve due to
excessive pressure build up. The temperature-pressure relief valve is
not intended for the constant relief of thermal expansion. This condition
is not covered under the limited warranty.
A properly sized thermal expansion tank should be installed on all
closed systems to control the harmful effects of thermal expansion.
Contact a plumbing service agency or your retail supplier regarding
the installation of a thermal expansion tank.
NOTE: To protect against untimely corrosion of hot and cold
water fi ttings, it is strongly recommended that dielectric unions
or couplings be installed on this water heater when connected
to copper pipe.
All gas piping must comply with local codes and ordinances or with
the current edition of the National Fuel Gas Code (ANSI Z223.1/
NFPA-54), whichever applies. Copper and brass tubing and
fi ttings
(except tin lined copper tubing) shall not be used.
FIGURE 10.
Figure 10 shows the typical attachment of the water piping to the
water heater. The water heater is equipped with 3/4 inch NPT water
connections.
NOTE: If using copper tubing, solder tubing to an adapter before
attaching the adapter to the cold water inlet connection. Do not
WATER PIPING
HOTTER WATER CAN SCALD:
Water heaters are intended to produce hot water. Water heated to
a temperature which will satisfy space heating, clothes washing,
dish washing, cleaning and other sanitizing needs can scald and
permanently injure you upon contact. Some people are more likely to
be permanently injured by hot water than others. These include the
elderly, children, the in
fi rm, or physically/mentally disabled. If anyone
using hot water in your home fi ts into one of these groups or if there
is a local code or state law requiring a certain temperature water at
the hot water tap, then you must take special precautions. In addition
to using the lowest possible temperature setting that satis
fi es your
hot water needs, a means such as a mixing valve should be used at
the hot water taps used by these people or at the water heater. See
Figure 2. Valves for reducing point of use temperature by mixing cold
and hot water are also available.
Consult a Quali fi ed Installer or Service Agency. Follow manufacturer’s
instructions for installation of the valves. Before changing the factory setting
on the thermostat, read the “Temperature Regulation” section in this manual.
This water heater shall not be connected to any heating systems or
component(s) used with a non-potable water heating appliance. All
piping components connected to this unit for space heating applications
shall be suitable for use with potable water. Toxic chemicals, such as
those used for boiler treatment shall not be introduced into this system.
When the system requires water for space heating at temperatures
higher than required for domestic water purposes, a mixing valve
must be installed. Please refer to Figure 2 for suggested piping
arrangement.
The water supply pressure should not exceed 80 psi. If this occurs, a
pressure reducing valve with a bypass should be installed in the cold
water inlet line. This should be placed on the supply to the entire house
in order to maintain equal hot and cold water pressures.
CLOSED WATER SYSTEMS
Water supply systems may, because of code requirements or such
conditions as high line pressure, among others, have installed
devices such as pressure reducing valves, check valves, and back
fl ow preventers. Devices such as these cause the water system to
be a closed system.
INSTALLING THE NEW WATER HEATER