Maintenance
Planned maintenance is the best way to avoid unnecessary
expense and inconvenience . Have this system inspected
at regular intervals by a trained and experienced service
technician . The following service intervals are typical for
average situations but will have to be adjusted to suit your
particular circumstances .
Fuel pressure settings, control settings, and linkage
adjustments should be made only by persons thoroughly
experienced with the burner and control system, and must not
be tampered with by persons without such experience .
Always replace covers on burner controls and boxes as the
electrical contacts are sensitive to dust and dirt . Perform
maintenance of flame safeguard, controls, gas valves, and
other such components in accordance with instructions
contained in the manufacturer’s bulletins .
Monthly
1 .
Check air filters and main supply fan drives
,
replacing if required .
2 .
Check flame signal
with a DC voltmeter .
Twice Yearly
1 .
Burner Air
- Check burner fan wheel for dirt buildup and
lint. Check combustion air intake louver and flue box for
dirt buildup and accumulation of windborne debris .
2 .
Cleaning
- Inspect flue tubes and combustion chamber,
cleaning as required . Keep burner vestibule clean . Dirt
and debris can result in burner air blockages .
Yearly
1 .
Gas Train
- Check all valves, piping and connections
for leakage . Remove burner gun assembly . Inspect and
clean pilot burner, flame rod, ignition electrode, main
burner discs, and blast tube . Check tightness of linkage
fasteners and bolts that could work loose from vibration
and movement .
2 .
Combustion
- Check quality of combustion . Test
CO
2
and CO and look for irregularities in fire shape. If
combustion characteristics have changed since the last
test, determine the cause . Changes in input changes
in the BTU content of gas being supplied, reduced
combustion air due to a dirty blower wheel, or flue
passages in need of cleaning can cause changes in CO
2
reading . When a readjustment seems necessary, do not
make the adjustment without first trying to determine if
the required change is not an indication that something
else is in need of correction .
3 .
Flame Safeguard
- Perform a flame failure check and
pilot turndown test . See control manufacturer’s bulletin
for further information .
4 .
Motor
- Motor life can be increased by proper oiling .
There are provisions in both end shields for relubrication .
Re-oil each bearing with 150 drops (approximately 1
teaspoon) SAE-20 oil .
5 .
Summer Shutdown
- If the burner is to be out of service
for the summer, turn off the burner control switch and
close the manual gas cocks .
6 .
Condensate Drain
- Inspect the Rear Condensate Drain
for blockage .
Flame Safeguard
See manufacturer’s bulletin for more detailed information or for
information on flame safeguard other than the RM7897A.
The Honeywell RM7897A is a microprocessor based integrated
burner control that will do self-diagnostics, troubleshooting, and
status indication, as well as the burner sequencing and flame
supervision .
Keyboard Display Module
The Honeywell S7800A1001 module is an optional device
available for use with the RM7897A . It can be a permanent
accessory added to the RM7897A or it can be carried by the
service technician as a tool that is very easy to mount when
servicing the RM7897A . It mounts directly onto the RM7897A
and has a 2 row by 20 column display . The module will indicate
flame signal dc volts, sequence status, sequence time, hold
status, lockout/alarm status, total hours of operation, total
cycles of operation, and can provide 127 different diagnostic
messages for troubleshooting the system .
The module will give a fault history . It can be mounted to the
RM7897A and will retrieve information on the six most recent
faults .
Consult the Honeywell bulletin 65-0090-1 “7800 Series,
Keyboard Display Module” and 65-0118-1 “7800 Series,
System Annunciation, Diagnostics and Troubleshooting .”
Maintenance
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IM 684-6 • ROOFTOP SYSTEMS
