Crest Audio FBN0751, Service Manual

Page: 34 / 56

2
Maintenance
34
Service Manual
IMG01141
GAS/AIR MANIFOLD COVER
GAS/AIR MANIFOLD GASKET
BURNER
PILOT ASSEMBLY
BURNER GASKET
GAS/AIR MANIFOLD
GAS/AIR MANIFOLD GASKET
BURNER TOP PLATE ASSEMBLY
FIBERBOARD
GASKET
NOTE: Be sure to pay close
attention to the Lochinvar logo.
Align the logo with the Lochinvar
logo on the gas/air manifold to
ensure proper assembly.
Pay close attention to the bolt
pattern, as the gas/air manifold
assembly can only be installed
one way.
LOCHINVAR LOGO
Figure 2-2 Burner Assembly
Failure to follow the torqueing
specifications listed above could result
in severe personal injury or death.
WARNING
4. Remove the top access panel(s) to gain access to the
gas/air manifold assembly.
5. Remove the gas/air manifold burner access cover
(FIG. 2-2).
6. Using care, remove the transition gas line from the
gas/air manifold and orifice assembly.
7. Remove the orifice assembly from inside the burner.
8. Remove the nuts/washers holding the burner to the
gas/air manifold assembly.
9. Remove the burner baffle and the burner from the
gas/air manifold assembly.
Review with owner
1. Review the Crest User’s Information Manual with the
owner.
2. Emphasize the need to perform the maintenance schedule
specified in the Crest 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.
NOTICE
The burner gasket, burner, burner
baffle, and gas/air manifold access
cover can only be installed in one
orientation. All of these parts will
have to be re-installed correctly.
To ensure all of these parts are
re-installed correctly, align the
logo on top of the gas/air manifold
cover with the logo on the gas/air
manifold as shown in FIG. 2-2. Be
certain to pay close attention to the
bolt pattern when re-installing the
above parts.
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 this manual for other
procedures to deal with low flame signal.
10. When replacing the burner, ensure gaskets are in good
condition and positioned correctly (FIG. 2-2).
11. When securing the burner and manifold, be sure to
tighten the nuts as follows:
a. Tighten the nuts in a star pattern sequence.
b. Tighten the 7/16" nuts, securing the
burner to the cast manifold to a torque of 8 ft.-lbs.
12. Re-install the orifice assembly and the transition gas line
removed in Steps 6 and 7.
13. Re-install the gas/air manifold burner access cover.
Tighten 3/8" nuts to 8 ft.-lbs. using the star pattern
sequence.
14. After firing the unit, re-tighten the nuts to the above
torque specifications.