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After installing the relief valve and filling and
pressurizing the system, test the operation
of the valve by lifting the lever. Make sure
the valve discharges freely. If the valve fails
to operate correctly, replace it with a new
relief valve. Ensure that the maximum BTU/H
rating on the pressure relief valve is equal to
or greater than the maximum input BTU/H
rating of the combination water heater.
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 through-
out its entire length.
•
Discharge line must pitch downward from the valve and terminate at least 6" above the floor drain,
making discharge clearly visible.
•
Discharge line shall terminate plain, not threaded, with a material serviceable for temperatures of 375ºF
or greater.
•
Do not pipe discharge to any location where freezing could occur.
•
No shutoff valve may be installed between the relief valve and water 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, replace it with a new relief valve.
•
Test relief valve at least once annually to ensure the waterway is clear. If valve does not operate, turn the
water heater "off" and call a plumber immediately.
•
Take care whenever operating relief valve to avoid scalding injury or property damage.
•
For water heaters installed with only a pressure relief valve, the separate storage vessel must have a
temperature and pressure relief valve installed. This relief valve shall comply with Relief Valves for Hot
Water Supply Systems, ANSI Z21.22 CSA4.4.
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.
Figure 25 – Relief Valve Details
43
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