Temperature-Pressure Relief Valve - A.O. Smith Residential Power Vent Gas Water Heaters with Hot Surface Ignition Instruction Manual

A.o. smith residential power vent gas water heaters with hot surface ignition instruction manual
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Installing the New Water Heater (cont'd)

Temperature-Pressure Relief Valve

WARNING
At the time of manufacture this water heater was provided
with a combination temperature-pressure relief valve certi-
fied by a nationally recognized testing laboratory that main-
tains periodic inspection of production of listed equipment
or materials, as meeting the requirements for Relief Valves
and Automatic Gas Shutoff Devices for Hot Water Supply
Systems, and the current edition of ANSI Z21.22 • CSA 4.4
and the code requirements of ASME. If replaced, the valve
must meet the requirements of local codes, but not less than
a combination temperature and pressure relief valve certi-
fied as meeting the requirements for Relief Valves and
Automatic Gas Shutoff Devices for Hot Water Supply
Systems, ANSI Z21.22 • CSA 4.4 by a nationally recognized
testing laboratory that maintains periodic inspection of pro-
duction of listed equipment or materials.
The valve must be marked with a maximum set pressure not
to exceed the marked hydrostatic working pressure of the
water heater (150 lbs./sq. in.) and a discharge capacity not
less than the water heater input rate as shown on the model
rating plate. (Electric heaters - watts divided by 1000 x 3412)
equal BTU/Hr. rate.
Your local jurisdictional authority, while mandating the use
of a temperature-pressure relief valve complying with ANSI
Z21.22 • CSA 4.4 and ASME, may require a valve model dif-
ferent from the one furnished with the water heater.
Compliance with such local requirements must be satisfied
by the installer or end user of the water heater with a local-
ly prescribed temperature-pressure relief valve installed in
the designated opening in the water heater in place of the
factory furnished valve.
For safe operation of the water heater, the relief valve must
not be removed from it's designated opening or plugged.
The temperature-pressure relief valve must be installed
directly into the fitting of the water heater designated for
the relief valve. Position the valve downward and provide
tubing so that any discharge will exit only within 6 inches
above, or at any distance below the structural floor. Be cer-
tain that no contact is made with any live electrical part. The
discharge opening must not be blocked or reduced in size
under any circumstances. Excessive length, over 30 feet, or
use of more than four elbows can cause restriction and
reduce the discharge capacity of the valve.
No valve or other obstruction is to be placed between the
relief valve and the tank. Do not connect tubing directly to
discharge drain unless a 6" air gap is provided. To prevent
bodily injury, hazard to life, or property damage, the relief
valve must be allowed to discharge water in quantities
should circumstances demand. If the discharge pipe is not
connected to a drain or other suitable means, the water flow
may cause property damage.
The discharge pipe:
—Must not be smaller in size than the outlet pipe size of the
valve, or have any reducing couplings or other restriction.
—Must not be plugged or blocked.
—Must be of material listed for hot water distribution.
—Must be installed so as to allow complete drainage of both
the temperature-pressure relief valve, and the discharge
pipe.
—Must terminate at an adequate drain.
—Must not have any valve between the relief valve and tank.
The temperature-pressure relief valve must be manually
operated at least once a year. Caution should be taken
to ensure that (1) no one is in front of or around the out-
let of the temperature-pressure relief valve discharge
line, and (2) the water manually discharged will not
cause any bodily injury or property damage because the
water may be extremely hot.
If after manually operating the valve, it fails to com-
pletely reset and continues to release water, immedi-
ately close the cold water inlet to the water heater, fol-
low the draining instructions, and replace the tempera-
ture-pressure relief valve with a new one.
HOT
RELIEF VALVE OPENING
"THIS WATER HEATER IS PROVIDED WITH A COMBINATION TEMPER-
ATURE-PRESSURE RELIEF VALVE. FOR SAFE OPERATION OF THE
WATER HEATER, THE RELIEF VALVE(S) MUST NOT BE REMOVED
FROM ITS DESIGNATED POINT OF INSTALLATION OR PLUGGED."
YOUR LOCAL JURISDICTIONAL AUTHORITY, WHILE MANDATING THE
USE OF A TEMPERATURE-PRESSURE RELIEF VALVE COMPLYING
WITH ANSI Z21.22 AND ASME, MAY REQUIRE A VALVE MODEL DIF-
FERENT FROM THE ONE FURNISHED WITH THE WATER HEATER.
COMPLIANCE WITH SUCH LOCAL REQUIREMENTS MUST BE SATIS-
FIED BY THE INSTALLER OR END USER OF THE WATER HEATER
WITH A LOCALLY PRESCRIBED TEMPERATURE-PRESSURE RELIEF
VALVE INSTALLED IN THE DESIGNATED OPENING IN THE WATER
HEATER.
SEE MANUAL HEADING—"TEMPERATURE-PRESSURE RELIEF
VALVES" FOR INSTALLATION AND MAINTENANCE OF RELIEF VALVE,
DISCHARGE LINE AND OTHER SAFETY PRECAUTIONS.
12
WARNING
COLD
TEMPERATURE-PRESSURE
RELIEF VALVE
DISCHARGE PIPE
(Do not cap or plug)
PROVIDE A 6" AIR
GAP BETWEEN THE
END OF THE
DISCHARGE PIPE
AND DRAIN

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