Condensing Water Heater
Gas Conversion
Guide
Model
NPE-180A/210A/240A
NPE-180S/210S/240S
This water heater is configured for Natural Gas from the factory.
If conversion to Propane Gas is required, the conversion kit supplied
with the water heater must be used.
WARNING
This conversion kit shall be installed by a qualified service agency* in
accordance with Navien America’s instructions and all applicable codes and
requirements of the authority having jurisdiction. The information in these
instructions must be followed to minimize the risk of fire or explosion or to
prevent property damage, personal injury or death. The qualified service
agency is responsible for the proper installation of this kit. The installation is
not proper and complete until the operation of the converted appliance is
checked as specified in the manufacturer’s instructions supplied with the kit.
٭
A qualified service agency is any individual, firm, corporation or
company which either in person or through a representative is engaged
in and is responsible for the connection, utilization, repair or servicing of
gas utilization equipment or accessories; who is experienced in such
work, familiar with all precautions required, and has complied with all of
the requirements of the authority having jurisdiction.
In Canada: The conversion shall be carried out in accordance with
the requirements of the provincial authorities having jurisdiction
and in accordance with the requirements of the CAN‐B149.1 and
CAN1‐B149.2 Installation Code.
Tools Required:
Phillips Screwdriver
Flathead Screwdriver
5/32” or 4mm Allen Wrench
Combustion Analyzer or Dual Port manometer
Gas Leak Detector
Included Items:
Gas Orifice (refer to below table)
Water
Heater
NG
LP
1STAGE
2STAGE
1STAGE
2STAGE
NPE-180A
NPE-180S
Ø4.80
Ø5.95
Ø3.80
Ø4.70
NPE-210A
NPE-210S
Ø6.10
Ø6.30
Ø4.50
Ø4.80
NPE-240A
NPE-240S
Ø6.10
Ø6.30
Ø4.50
Ø4.80
Table 1. Orifice size
Gas Pressure and Conversion Kit Number Labels
6. Once the Gas Orifice is exposed, remove the two screws that
hold the part in place. Remove the Gas Orifice from its housing
and prepare the new Gas Orifice for the LP conversion for
installation.
Figure 4. Access to Gas Orifice in Fan Assembly
WARNING
DO NOT adjust or attempt to measure gas valve outlet
pressure. The gas valve is factory-set for the correct outlet
pressure. This setting is suitable for natural gas and propane,
requiring no field adjustment.
Attempting to alter or measure the gas valve outlet pressure
could result in damage to the valve, causing potential severe
personal injury, death or substantial property damage Navien
water heaters are shipped ready to fire natural gas ONLY.
DANGER
See Figure 5. Inspect the O-ring between the gas valve and gas valve inlet
adapter whenever they are disassembled. The O-ring must be in good
condition and must be installed. Failure to comply will cause a gas leak,
resulting in severe personal injury or death.
Procedure:
1. Turn off both gas and water supply to the water heater
2. Using a Phillips hand screwdriver, remove 4 screws (2 from the top and
2 from the bottom) of the front cover assembly to gain access to the
internal components. See Figure 1 for illustration of the front cover
on the unit.
3. Once the front cover is removed, place it in a safe location to prevent
accidental damage. With the internal component exposed, locate the gas
inlet pipe and the Gas Valve near the left side of the unit which are
highlighted in Figure 2.
4. Use a Phillips screwdriver to remove the two screws at
Location A - the connection below the Gas Valve where it
connects to the pipe. See Figure 3 for reference. Once the
screws are removed, carefully separate the pipe from the
Gas Valve.
5. Once the gas inlet pipe is detached from the Gas Valve, find
Location B - the connection above the Gas Valve where it is
attached to the Fan Motor Assembly. Carefully remove the
four screws by hand using a Phillips screwdriver and pull the
Gas Valve away from the Fan Assembly to access the Gas
Orifice.
Figure 3. Detaching Gas Valve from
Gas Inlet Pipe and Fan Motor Assembly
Figure 6. Orifice identification
7. Replace the old Orifice piece with the new part for use with LP
gas. Ensure that the Orifice is properly seated inside the port
before proceeding to the next step.
8. Replace the gas inlet pipe to its original position and use all
screws to secure all connections.
Do not overtighten as this may damage or crack
the components.
DANGER
Inspect the O-ring between the gas valve and gas valve inlet adapter
whenever they are disassembled. The O-ring must be in good condition
and must be installed. Failure to comply will cause a gas leak, resulting
in severe personal injury or death.
9. Set the Front Panel Dip switch according to the gas type.
WARNING
Be sure to turn off the power before changing the DIP switch setting.
10. Turn on the gas and water supply to the water heater.
Location B:
Remove four
(4) screws here
Location A:
Remove two (2)
screws here
Gas Inlet
Pipe
Gas Valve
Figure 1.
NPE Series Front cover
Figure 2.
NPE Series Internal Components
Gas Orifice
O-ring
Figure 5.
Exploded view of Gas assembly
Remove two (2)
screws here
