Navien NCB-190/060H Installation & Operation Manual page 22

WARNING
Installing the pressure relief valve improperly
●
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.
The pressure relief valve must be installed
●
at the boiler and in the vertical position, as
shown in this section, with the drain pipe
outlet exiting the side of the pressure relief
valve horizontally and elbowing down.
CAUTION
Install the pressure relief valve as close to the
boiler as possible. No other valve should be
installed between the pressure relief valve and
boiler.
When installing the pressure relief valve, follow
these guidelines:
Ensure that the valve's discharge capacity is equal
●
to or greater than the maximum pressure rating
of the boiler's space heating system.
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 boiler.
Direct the discharge piping of the pressure relief
●
valve so that hot water does not splash on the
operator or 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 the
discharge clearly visible.
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.
22 Installing the System Piping
Ensure that the discharge line provides complete
●
and unobstructed drainage. Do not install a
reducing coupling or other restrictions on the
discharge line.
If the relief valve discharges periodically, this may be
caused by thermal expansion when the expansion
tank is full or undersized. Do not plug the relief
valve.
Refer to the following illustration and install a
pressure relief valve to the pressure relief valve
adapter located on the top corner of the NCB-H
boiler. Watts M330-M1 pressure relief valve (3/4 in,
HV, Max 30 psi) is provided with the boiler.
Pressure
Relief
Valve
WARNING
To avoid water damage or scalding, direct the
discharge line to a safe place for disposal.
CAUTION
All field supplied pressure relief valves must
●
be ASME certified.
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
injury or property damage. Contact with
the discharged water may result in severe
personal injury.