Navien NPE-180A Installation Manual page 25

G H
Domestic
Hot Water
Domestic
Recirculation
Return
Recirculation Using Two Pumps
(Navien Internal Pump & External Pump)
3.4.4 Connecting a Pressure Relief Valve
WARNING
Improper installation of the pressure relief valve may result
in property damage, personal injury, or death. Follow all
instructions and guidelines when installing the pressure
relief valve. The valve should be installed only by a licensed
professional.
C
Condensate
Gas
Domestic
Cold Water
To complete the installation of the water heater, you must install
an approved 3 / in, maximum 150 PSI pressure relief valve on the
4
hot water outlet. The water heater has a built-in high temperature
shut off switch, so install a "pressure only" relief valve. This valve is
not supplied, but is required. The following examples are approved
for use with the water heater:
Wilkins P-1000A (Zurn Industries)
Conbraco 17-402-04
Watts Industries 3L(M7)
Cash Acme FWL-2, 3 / in
4
The pressure relief valve should be placed as close to the water
heater as possible. No other valve should be placed between the
pressure relief valve and the water heater.
Pressure
relief valve
Shut-off Valve
Gas Hot water
When installing the valve, follow these guidelines:
Ensure that the discharge capacity of the pressure relief valve
is equal to or greater than the maximum pressure rating of the
water heater.
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 water heater.
Direct the discharge piping of the pressure relief valve so that
hot water will not splash on anyone or any nearby equipment.
Attach the discharge line to the pressure relief valve and run the
end of the line to within 6-12 in (150-300 mm) of the floor.
Ensure that the discharge line will allow free and complete
drainage without restriction. Do not install a reducing coupling
or other restriction on the discharge line.
If the relief valve discharges periodically, this may be due to
thermal expansion in a closed water supply system. Contact the
water supplier or local plumbing inspector on how to correct
this situation. Do not plug the relief valve.
Cold water
Installing the Water Heater 25