Replacement of Parts 121
6.1 Replacement Procedure
CAUTION
1. When performing maintenance and/or servicing the
water heater, always turn off the electric power, gas and
water shut-off valve. Wait for the water heater to become
cool. Be careful to avoid injury to your fingers on sharp
edges.
2. Drain all water from the water heater when removing the
waterway components.
3. Before any disassembly, make sure that all issues and error
codes are properly diagnosed.
4. Handle all parts carefully.
5. When reassembling, prevent any foreign substance, i.e.
dust, etc. from entering back into the water heater.
6. After reassembling, check for gas and water leakage.
Then, test for proper ignition. Make sure that there is no
gas leakage from the gas connections by testing with
soap bubble solution. Bubbles indicate a gas leak that
must be corrected.
7. Check the performance and operation after the water
heater has been serviced.
To remove and replace any parts from the water heater, you will
need a screwdriver that is at least 8 ~ 10 inches long. A flashlight
and magnetic tip are also recommended. Navien recommends
the use of a parts tray to hold small parts and screws. All of the
hardware is essential to the proper operation of the unit upon
re-assembly.
NOTE
When disassembling and reassembling the water heater, refer
the components diagram & parts list.
6.2 Components Replacement
Instructions
6.2.1 PCB
1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit.
4. Remove the screws that are located near the top and bottom
of the PCB that hold it in place as shown in Figure 1.
Figure 1
5. Disconnect all wiring connectors from the PCB as shown in
Figure 2.
Figure 2
6. Remove the 2 screws located on the back of the case.
6. Replacement of Parts
