Navien NPE-32AWE Installation Manual page 26

3.4.3 Connecting a Pressure Relief Valve
WARNING
Improper installation of the pressure relief valve may
result in property damage or personal injury. Follow all
instructions and guidelines when installing the pressure
relief valve. The valve should be installed only by a licensed
professional.
To complete the installation of the water heater, you must
install an approved 20mm, maximum 10 bar pressure relief valve
on the hot water outlet. The water heater has a built-in high
valve. This valve is supplied along with the water heater.
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.
Gas Hot water
26 Installing the Water Heater
Pressure
relief valve
Shut-off Valve
Cold 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 kW rating on the pressure relief
valve is equal to or greater than the maximum input kW 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 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.