Navien NHW700, Installation Manual

Page: 34 / 83

33 Installing the Water Heater
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 drain making discharge
clearly visible.
●
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.
●
Do not direct the discharge line to a location
where freezing could occur.
●
Ensure that the discharge line is not plugged or
obstructed.
●
After filling and pressurizing the system, test
the relief valve operation by lifting the lever. If
the valve fails to operate correctly, immediately
replace the relief valve.
●
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.
WARNING
●
To avoid potential property damage or
personal injury, check the pressure relief
valve at least once every three years by
manually operating the valve to ensure
proper operation.
●
Before manually operating the valve, check
the discharge line and make sure that the
hot discharge water will not cause personal
or property damages. Contact with the
discharge water may result in severe personal
injury.
3.4.5 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.
To complete the installation of the water heater,
you must install an approved
3
/
4
in, maximum 150
PSI pressure relief valve on the 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
/
4
in
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.
Shut-Off
Valve
Pressure
Relief
Valve
Cold Water Hot Water Gas
WARNING
To avoid water damage or scalding, direct the
discharge line to a safe place for disposal.