Knight 100 Series, Service Manual

Page: 36 / 52

2
Maintenance
36
Check flame signal
1. At high fire the flame signal shown on the display should
be at least 10 microamps.
2. A lower flame signal may indicate a fouled or damaged
flame sense electrode. If cleaning the flame sense electrode
does not improve, ground wiring is in good condition,
and ground continuity is satisfactory, replace the flame
sense electrode.
3. See Section 3 - Troubleshooting in this manual for other
procedures to deal with low flame signal.
Review with owner
1. Review the Knight Fire Tube Boiler User’s Information
Manual with the owner.
2. Emphasize the need to perform the maintenance
schedule specified in the Knight Fire Tube Boiler User’s
Information Manual (and in this manual as well).
3. Remind the owner of the need to call a licensed contractor
should the boiler or system exhibit any unusual behavior.
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.
The boiler contains ceramic fiber materials.
Use care when handling these materials
per instructions in this manual. Failure
to comply could result in severe personal
injury.
Service Manual
Cleaning boiler heat exchanger
1. Shut down boiler:
• Follow the “To Turn Off Gas to Appliance” instructions
for the boiler in Section 10 - Startup of the Knight Fire
Tube Installation and Operation Manual.
• Do not drain the boiler unless it will be exposed to
freezing temperatures. If using freeze prevention fluid
in system, do not drain.
2. Allow time for the boiler to cool to room temperature if
it has been firing.
3. Remove the top and front access panels (no tools
required for removal) along with the bezel.
4. Remove the wiring from the ignitor, flame rod, and the
fan. Remove the reference tubing from the air intake.
5. Loosen the band clamp on the air intake coupling using
a field provided 5/16" driver.
6. Remove the 4mm screws holding the fan to the heat
exchanger top plate.
7. Loosen the union on the venturi
8. The fan and the venturi may now be removed from the
unit together by sliding the fan away from the air intake.
9. Remove the 10mm nuts securing the heat exchanger top
plate to gain access to the heat exchanger and set aside.
10. Disconnect the condensate hose from the condensate trap
and route to drain.
11. Use a vacuum cleaner to remove any accumulation on the
boiler heating surfaces. Do not use any solvent.
12. Using a clean cloth dampened with warm water, wipe out
the combustion chamber. Rinse out debris with a low
pressure water supply.
13. Allow the heat exchanger to thoroughly dry.
14. Reassemble the unit in reverse order of component
removal, and re-install the condensate hose.
15. Perform a combustion analysis by following the
instructions in Section 3 - Troubleshooting - Check
Flame and Combustion of this manual.
16. Resume operation.
Damaged gaskets and seals in the
system can result in substantial property
damage. Ensure that damaged or torn
gaskets are replaced.
⚠
WARNING
⚠
WARNING