Full Service - Navien NCB500-2S/37K Service Manual

Checking the CO₂
1. Check the CO₂ readings at full load and low load.
2. Check the CO readings and combustion performance
(CO/CO₂ ratio).
3. Check the CO readings and combustion performance.
For more information, refer to the 15th step in "4.3 Gas
Conversion" on page 19. The combustion reading (CO/CO₂
ratio) must be less than 0.004.
4. If the combustion reading (CO/CO₂ ratio) is greater than
this, and the integrity of the complete flue system and
combustion circuit seals has been verified, and the inlet gas
pressure and gas rate are satisfactory either:
Perform the full service. For more information, refer to
●
"8.5.2 Full Service" on page 108.
Set the Gas Valve. For more information, refer to "4.2
●
Measuring the Inlet Gas Pressure" on page 18.
Review with the Owner
1. Review the User's Information Manual with the owner.
2. Emphasize the need to perform the maintenance schedule.
3. Remind the owner of the need to call a licensed contractor
should the boiler or system exhibit any unusual behaviour.
4. Remind the owner to follow the proper shutdown procedure
and to schedule an annual start-up at the beginning of the
next heating season.
5. After servicing, complete the relevant Service Interval
Record section of the Benchmark Checklist located on the
inside back page of this document.

8.5.2 Full Service

For reasons of safety and economy, it is recommended that the
boiler is serviced annually. Servicing must be performed by a
competent person in accordance with BS 7967-4. After servicing,
complete the relevant Service Interval Record section of the
Benchmark Checklist located on the inside back page of this
document.
Where a full service is required, refer to "8.5.1 Interim
Note
Service" on page 106.
108 Inspection and Maintenance Schedule
1. Press the Power button (
the boiler.
2. Disconnect the power supply to the boiler.
3. Turn off both gas and water supply to the boiler.
Wait at least 30 minutes for the heat exchanger to
Note
cool down.
4. Unfasten the 2 latches (at the top) and remove 2 screws (at
the bottom) to remove the front cover to gain access to the
internal components.
5. Once the front cover is removed, place it in a safe location to
prevent accidental damage.
) on the front panel to turn off