Aerovent IM-500 - Manual (Page 17)

17 Aerovent IM-500
If lamp #11 does not light, check:
1. Is lamp #11 getting power or is the bulb defective?
2. High temperature limit thermostat. (Manual reset)
3. Not properly set.
If lamp #12 does not light, check:
1. Is lamp #12 getting power or is the bulb defective?
2. Airflow switch adjustment
3. Dirty filters or loose belts.
If lamps #13 & #14 do not light, check:
1. Are lamps #13 and #14 getting power or are the bulbs
defective?
2. Reset button on the RM7890 flame relay.
3. Connection of the wire #13 to terminal 10 on the flame
relay and wire #14 to terminal 8.
4. C7027A flame sensor. Remove from the sighting tube
and observe UV tube during new sequence. If it lights
(bright orange) or flickers when fan starts, it is defective.
(Replace) It should flicker when it sees a flame. If it
glows solid, replace.
5. If it does not flicker occasionally or light, replace the
RM7890.
NOTE: #13 and #14 come on at the same time. #13 will
go out after flame is proven. #14 will stay on for the ten
second flame establishing period. #15 is energized when
#13 is turned off.
If lamp #15 does not light, check:
1. Is lamp #15 getting power or is the bulb defective?
2. Are the valves opening and staying open?
3. Is the flame light on the flame relay coming on? The
flame being proven during PFEP.
4. See check out procedure for C7027A sensor under #13
& #14.
If lamp #16 does not light, check:
1. Is lamp #16 getting power or is the bulb defective?
2. Operation of safety shut-off valve.
3. Auxiliary switch in the safety shut-off valve.
NOTE: If all lights come on for approximately one minute,
then #14, #15, and #16 go out, followed by a shutdown
in 15 seconds, check flow of gas through valves to burner,
and also burner port openings.
When unit has been checked, turn the circuit analyzer off.
These are 20,000 hour neon lamps and should last the life
of the equipment, unless the analyzer is left on after use.
NUISANCE SHUTDOWNS
Occasionally the unit may shut down during normal opera-
tion. Simply by turning the selector switch to the “off ”
position for 30 seconds, then back to “Winter”, the unit will
start again through a complete cycle and run normally. This
condition could be caused by one of the following:
1. Momentary Loss of Power
2. Low Temperature Limit
3. Airflow Switch
EXAMPLE: Low limit opens during operation or remains
open on initial start up due to insufficient heat. Manually
reset the unit by turning the selector switch to “OFF”, then
back “ON”. All other controls will require manual reset at
the control, except the airflow switch.
Notes:
Usually nuisance shut downs are one of two things:
a) Low temperature limit: The unit shuts down as soon as
the reset timer times out.
b) Air Flow Switch: Typically these are periodic shut downs
and do not happen predictably.
FOR TROUBLE SHOOTING TEMPERATURE
CONTROLS CONSULT THE MAXITROL
BULLETIN FOUND AT WWW.MAXITROL.COM.
Annual Maintenance
Recommendations
MAINTENANCE SCHEDULING
Prior to heating season each year, the following inspections
and tests should be made to be sure the unit is in proper
operating condition for the heating season.
Turn off power at the main disconnect switch. Examine
the inside of the air make-up unit. See that the thermostat
and temperature sensing elements are in place and their
support brackets are solid. Examine the damper blades and
linkage to insure that they have not been damaged. Turn
the propeller by hand to be sure the bearings turn freely
with no rough spots or noise. Be sure the grease lines and
fittings are intact. Check the velocity monitor to be sure
the venturi and the tubing to the airflow switch are not
obstructed.
BLOWER ASSEMBLY
The blower assembly includes the fan bearings, drive
sheaves and belts.
Bearings should be checked for any unusual wear and
replaced if needed. Also make sure bearings are secure and
locking collars tight.
Check the belt drive for proper tightness and align-
ment. If belts are beginning to wear, replace them. If the
sheaves show signs of wear in the grooves, replace both
fan and motor sheaves and the belts. (New belts should
be retightened after 24 hours of operating and
again after a week’s operation.)