56
Installation & Operation Manual
11
Maintenance
Check burner flame
1. Inspect flame through observation windows.
2. If the flame is unsatisfactory at either high fire or low
fire, remove and clean the burner. Clean the burner
thoroughly using a vacuum cleaner or compressed
air. Do not use compressed air to clean the burner if
cleaning is performed inside a building.
• Shut down the boiler:
- Follow the “To Turn Off Gas to Appliance”
instructions for the boiler in Section 9 -
Startup.
- Do not drain the boiler unless it will be
exposed to freezing temperatures. If using
freeze prevention fluid in system, do not drain.
3. Allow time for the boiler to cool to room temperature
if it has been firing.
4. Remove the top access panel to remove the gas/air
manifold assembly.
5. Remove the nuts securing the burner to the burner
mounting plate. Remove the burner (FIG. 11-2).
6. When replacing the burner, ensure gaskets are in good
condition and positioned correctly (FIG. 11-2).
7. When securing the burner mounting plate, burner,
and manifold, be sure to tighten the nuts as follows:
a. Tighten the nuts in a star pattern sequence.
b. When securing the burner mounting plate to the
heat exchanger be sure to tighten the nuts, but DO
NOT over-tighten. Tighten the 3/8" nuts to a torque
setting of 25 ft.-lbs.
c. For Models 1.5, 2.0, 2.5, 3.0 and 3.5 tighten the 1/4"
or 5/16" nuts, securing the burner to the cast
manifold to a torque of 8 ft.-lbs and the 3/8" nuts
securing the burner to the mounting plate to a torque
of 25 ft.-lbs.
For Models 4.0 and 5.0 tighten the 3/8" nuts,
securing the burner to the manifold and the burner
to the mounting plate to a torque of 25 ft.-lbs.
d. After firing the unit, re-tighten the nuts to the
above torque specifications.
BURNER
ASSEMBLY
MANIFOLD
GASKET
AIR/GAS
MANIFOLD
INSULATION
BURNER
GASKET
BURNER PLATE
FIBERBOARD
Figure 11-2 Burner Assembly
Check flame signal
1. At high fire of each combustion system, 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 electrodes 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 the Crest Service Manual for
other procedures to deal with low flame signal.
Failure to follow the torqueing
specifications listed above could result
in severe personal injury or death.
WARNING
