Temperature-Pressure Relief Valve; T&P Valve Discharge Pipe Requirements - A.O. Smith GPVX 75L Series Installation And Operating Manual

TEMPERATURE-PRESSURE RELIEF VALVE

WARNING
This water heater is provided with a properly rated/sized
and certified combination Temperature-Pressure Relief
Valve (T&P valve) by the manufacturer. The valve is
certified by a nationally recognized testing laboratory
that maintains periodic inspection of production of listed
equipment of materials as meeting the requirements for
Relief Valves for Hot Water Supply Systems, ANSI
Z21.22-CSA 4.4, and the code requirements of ASME.
If replaced, the new T&P valve must meet the requirements
of local codes, but not less than a combination temperature-
pressure relief valve rated/sized and certified as indicated
in the above paragraph. The new valve must be marked
with a maximum set pressure not to exceed the marked
hydrostatic working pressure of the water heater (150 psi)
and a discharge capacity not less than the water heater
Btu/hr input rate as shown on the water heater's model
rating plate.
For safe operation of the water heater, the temperature-
pressure relief valve must not be removed from its
designated opening nor plugged. The T&P valve must
be installed directly into the fitting of the water heater
designed for the relief valve. Install discharge piping so
that any discharge will exit the pipe within 300mm (12 in.)
above an adequate floor drain, or external to the building.
In cold climates it is recommended that it be terminated at
an adequate drain inside the building. Be certain 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
9.15m [30 ft.]), 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 T&P valve and the tank. Do not connect discharge
piping directly to the drain unless a maximum of 300mm
(12 in.) air gap is provided. To prevent bodily injury,
hazard to life, or property damage, the relief valve must
be allowed to discharge water in adequate quantities
should circumstances demand. If the discharge pipe is not
100271597
Explosion Hazard
•
Temperature-pressure relief
valve must comply with ANSI
Z21.22-CSA4.4 and ASME
code.
•
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
•
Do not plug, block, or cap the
discharge line.
•
Failure to follow this warning
can result in excessive tank
pressure, serious injury or
death.
connected to a drain or other suitable means, the water
flow may cause property damage.
CAUTION
Water Damage Hazard
Temperature-pressure relief valve discharge pipe
•
must terminate at an adequate drain.
T&P valve discharge pipe requirements:
•
Must not be smaller than the pipe size of the relief
valve or have any reducing coupling installed in the
discharge line.
•
Must not be capped, blocked, plugged or contain
any valve between the relief valve and the end of the
discharge line.
•
Must terminate a maximum of 300mm (12") above a
floor drain or external to the building. In cold climates, it
is recommended that the discharge pipe be terminated
at an adequate drain inside the building.
•
Must be capable of withstanding 121°C (250°F) without
distortion.
•
Must be installed to allow complete drainage of both
the valve and discharge line.
Important: Allowing the T&P discharge pipe to blow down
into the drain pan can result in flooding of the area and
result in serious property damage. Significant quantities
of water can be released by an open T&P valve. Ensure
the system has adequate capacity to channel water to
the drain.
DANGER
HOT
HOT
BURN
The T&P valve must be manually operated at least once
a year. Caution should be taken to ensure (1) no one is
in front of or around the outlet of the 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 completely reset and continues to release water,
immediately close the cold-water inlet to the water heater,
follow the draining instructions in this manual, and replace
the temperature-pressure relief valve with a properly rated/
sized new one.
• Burn hazard.
• Hot water discharge.
• Keep clear of
temperature-pressure
relief valve discharge.
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