Navien NCB300-28K, Service Manual

Page: 90 / 108

Replacement of Parts 89
9. Check that all gas connections are tightly sealed to ensure
that no gas leaks are present.
10. Turn on water supply, power supply, and gas supply to the
unit.
11. Verify the gas pressures to the unit with the values provided
in this Service Manual.
6.2.7 Condensate Trap
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 pin that secures the condensate drain cap
and then remove the cap. Use a bucket to collect the
condensate.
Figure 13
5. Detach the condensate piping from the unit.
6. Remove the two screws located at the bottom of the unit
that are attached to the condensate trap.
7. Loosen the clip that secures the hose to the condensate
trap, and then pull off the hose.
8. Remove the old condensation trap and replace it with the
new part.
9. Reconnect the hose to the condensate trap.
10. Reattach the condensation trap to the unit and secure it
using the five screws.
11. Replace the front panel to its original position.
12. Turn on the water supply, power supply, and gas supply to
the unit.
Note
Ensure that the condensate drain trap is completely
inserted into the condensate fitting to eliminate
leaking. Use the pin to secure the cap to the fitting.
6.2.6 Main Gas Valve
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 two screws and disconnect the wiring
connector at the gas valve.
Figure 11
5. Remove the two screws located at the bottom of the unit
that are attached to the gas valve.
Figure 12
6. Replace the old gas valve with the new part.
7. Reconnect the gas valve assembly to the unit by using the
two screws at the boiler.
8. Reattach the gas valve wiring connector.
WARNING
Failure to correctly assemble the components according to
these instructions may result in a gas leak or explosion.