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E. Temperature and Pressure Relief Valve
On all models, an appropriate temperature and pressure
(T&P) valve must be supplied and installed as detailed in the
piping diagrams in this installation manual.
Use both thread tape and pipe dope to install an NPT brass
T&P relief valve for hot water storage tanks, as required by
local codes but not less than valves certified as meeting the
requirements for relief valves for hot water heaters (ANSI
Z21.22 / CSA 4.4) by a nationally recognized lab that maintains
periodic inspection of production listed equipment. Make sure
the relief valve is sized to the BTU/Hour capacity of the water
heater. The T&P valve must be plumbed down so discharge
can exit at least 6" above the structural floor. The relief line
cannot be in contact with any live electrical parts. If the
relief valve constantly weeps install an expansion tank. See
expansion tank manufacturer's instructions for suggestions.
To avoid water damage or scalding due to relief valve
operation:
•
Discharge line must be connected to relief valve outlet
and run to a safe place of disposal. Terminate the
discharge line in a manner that will prevent possibility
of severe burns or property damage should the relief
valve discharge.
•
Discharge line must be as short as possible and
the same size as the valve discharge connection
throughout its entire length.
•
Discharge line must pitch downward from the valve
and terminate at least 6" above the floor drain, making
discharge clearly visible.
•
The discharge line shall terminate plain, not threaded,
with a material serviceable for temperatures of 375
or greater.
•
Do not pipe discharge to any location where freezing
could occur.
•
No valve may be installed between the relief valve and
heater or in the discharge line. Do not plug or place
any obstruction in the discharge line.
•
Test the operation of the relief valve after filling and
pressurizing the system by lifting the lever. Make sure
the valve discharges freely. If the valve fails to operate
correctly, immediately replace with a new properly
rated relief valve.
•
Test T&P valve at least once annually to ensure the
waterway is clear. If valve does not operate, turn the
heater "off" and call a plumber immediately.
•
Take care whenever operating relief valve to avoid
scalding injury or property damage.
FAILURE TO COMPLY WITH THE ABOVE GUIDELINES
COULD RESULT IN FAILURE OF RELIEF VALVE OPERATION,
RESULTING IN POSSIBILITY OF SUBSTANTIAL PROPERTY
DAMAGE, SEVERE PERSONAL INJURY, OR DEATH.
Do not thread a cap or plug into the relief valve or relief
valve line under any circumstances! Explosion and property
damage, serious injury, or death may result.
RE-INSPECTION OF T&P RELIEF VALVES: T&P valves should
be inspected AT LEAST ONCE EVERY THREE YEARS, and
replaced if necessary, by a licensed plumbing contractor or
qualified service technician to ensure that the product has not
been affected by corrosive water conditions and to ensure that
the valve and discharge line have not been altered or tampered
with illegally. Certain naturally occuring conditions may corrode
the valve and its components over time, rendering the valve
inoperative. Such conditions can only be detected if the valve
and its components are physically removed and inspected.
Do not attempt to conduct an inspection on your own.
Contact your plumbing contractor for a re-inspection to assure
continued safety.
FAILURE TO RE-INSPECT THE T&P VALVE AS DIRECTED
COULD RESULT IN UNSAFE TEMPERATURE AND/OR
PRESSURE BUILD-UP WHICH CAN RESULT IN PROPERTY
DAMAGE, SERIOUS PERSONAL INJURY, OR DEATH.
F. Scalding
An ASSE 1017 or ASSE 1070 temperature limiting or mixing
valve is recommended in installations servicing disabled or
elderly persons, or children. Mixing valves do not eliminate the
risk of scalding.
To avoid scalding:
•
Set the water heater set point temperature as low as
possible.
•
Feel water before bathing or showering.
•
If thermostatic valves are required, use devices
specifically designed for such purpose. Install these
devices in accordance with instructions provided by the
F
o
manufacturer.
Failure to install a temperature limiting or mixing valve and
follow these instructions could result in property damage,
severe personal injury, or death due to scalds.
Approximate Time / Temperature Relationships in Scalds
120
F
o
125
o
F
130
o
F
135
o
F
140
F
o
145
o
F
150
o
F
155
o
F
Table 2 - Approximate Time / Temperature Relationships in Scalds
7
More than 5 minutes
1 1/2 to 2 minutes
About 30 seconds
About 10 seconds
Less than 5 seconds
Less than 3 seconds
About 1 1/2 seconds
About 1 second
whl-007 Rev. 1.12.16
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