John Wood Commercial - 300-400K BTU - Manual (Page 15)

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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.
Water Damage Hazard
Temperature-Pressure Relief Valve discharge
pipe must terminate at adequate drain.
•
CAUTION
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 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
relief valve and the drain.
Burn hazard.
Hot water discharge.
Keep clear of Temperature-
Pressure Relief Valve
discharge outlet.
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 14.
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.
temperature-pressure relief ValVe
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.
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 = 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 label.
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. Call the toll free technical
support phone number listed on the back cover of this manual
for technical assistance in sizing a Temperature-Pressure relief
Valve for remote storage tanks.
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 relief valve must be allowed to discharge