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TEMPERATURE-PRESSURE RELIEF VALVE
This water heater is provided with a properly rated/sized and certified
combination Temperature-Pressure Relief Valve (T&P relief 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 =
1,035 kPa) and a discharge capacity not less than the water heater Btu/
hr or kW input rate as shown on the water heater's model rating plate.
NOTE: In addition to the factory installed Temperature-Pressure
Relief Valve on the water heater, each remote storage tank that may
be installed and piped to a water heating appliance must also have
its own properly sized, rated and approved Temperature-Pressure
Relief Valve installed.
For safe operation of the water heater, the Temperature-Pressure
Relief Valve must not be removed from its designated opening nor
plugged. The Temperature-Pressure Relief 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
6 inches (15.2 cm) 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 30 feet (9.14 m), 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
Temperature-Pressure Relief Valve and the tank. Do not connect
discharge piping directly to the drain unless a 6" (15.2 cm) air gap
is provided. To prevent bodily injury, hazard to life, or property
damage, the temperature-pressure relief valve must be allowed
to discharge water in adequate 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.
CAUTION
Water Damage Hazard
•
Temperature-Pressure Relief Valve discharge
pipe must terminate at adequate drain.
Explosion Hazard
Temperature-Pressure Relief Valve
must comply with ANSI Z21.22-
CSA 4.4 and ASME code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.
T&P VALVE DISCHARGE PIPE REQUIREMENTS:
•
Shall not be smaller in size than the outlet pipe size of the valve,
or have any reducing couplings or other restrictions.
•
Shall not be plugged or blocked.
•
Shall not be exposed to freezing temperatures.
•
Shall be of material listed for hot water distribution.
•
Shall be installed so as to allow complete drainage of both the
Temperature-Pressure Relief Valve and the discharge pipe.
•
Must terminate a maximum of six inches (15.2 cm) 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.
•
Shall not have any valve or other obstruction between the
temperature-pressure relief valve and the drain.
The Temperature-Pressure Relief Valve must be manually
operated at least twice a year. Caution should be taken to ensure
that (1) no one is in front of or around the outlet 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 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.
NOTE: The purpose of a Temperature-Pressure Relief Valve is to
prevent excessive temperatures and pressures in the storage tank.
The T&P valve is not intended for the constant relief of thermal
expansion. A properly sized thermal expansion tank must be
installed on all closed systems to control thermal expansion, see
Closed Water Systems and Thermal Expansion on Page 21.
If you do not understand these instructions or have any questions
regarding the Temperature-Pressure Relief Valve call the toll
free number listed on the back cover of this manual for technical
assistance.
CONDENSATE PIPING
The water heaters covered in this manual are condensing
appliances and require a building drain to be located in close
proximity to allow the condensate to drain safely.
Condensate drains from the water heater at the exhaust elbow
located at the bottom. The field installed condensate drain line
must not be elevated above the condensate drain connection on
the condensate trap, see Figure 12. If the condensate does not
drain properly it will build up in the exhaust (vent) elbow. This will
restrict the flow of flue gases and cause the Blocked Exhaust
pressure switch to open its contacts. The control system monitors
all pressure switches, if the Blocked Exhaust Switch contacts are
open the control system will lock out and disable heating operation.
The "Blocked Exhaust" Fault message will be displayed on the
control system's LCD.
The Condensate Cleanout Cap must be on and tight when unit is
in operation.
NOTE: If the "Blocked Exhaust " Fault message is ever displayed
on the control system LCD, check the condensate drain first and
ensure it is not blocked.
22
Burn hazard.
Hot water discharge.
Keep clear of Temperature-
Pressure Relief Valve
discharge outlet.
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