Chapter 5: Troubleshooting
Troubleshooting Symptoms
Service Manual 5-5
S20 Canopy works in one direction 
but not the other.
Defective canopy motor. Check the voltage to the 
canopy motor for both up and 
down movement. Refer to the 
Tips section (5.3.4). If OK, 
replace the canopy motor/
gearbox. 
Defective 50 pin ribbon 
cable between the relay 
and control board.
Check for continuity on pins 23, 
24, 26, 27 (motor control 
signals). If defective, replace 
the cable.
Defective relay board. Replace relay board.
S21 Canopy travels down part way 
then stops or goes very slow 
for the last part.
An object fell into the 
opening behind the radiant 
heater floppy door.
Check that the floppy door, 
located behind the radiant 
heater moves freely. Look to be 
sure nothing has fallen behind 
the door.
S22 Canopy travels down part way 
then stops and gives an in-
transition alarm.
Heater doors are mechanically 
closed, but switch status on 
Service screen does not 
indicate closed.
Heater door switch(es) is 
(are) malfunctioning.
Remove heater housing cover 
to access door switches. Use a 
small screw driver to adjust the 
switches so that two distinct 
clicks are heard when switches 
move. If necessary, replace 
switches.
Heater door sensor wire 
harness (6600-0752-700) is 
loose or damaged.
Remove heater housing cover 
to access and inspect the wire 
harness. If necessary, reinstall 
and/or replace the harness. 
Before removing the harness, 
note which switch pins are 
connected to which harness 
lead for proper re-installation.
S23 Canopy rises slowly and stops 
before doors are opened fully. 
Broken rungs in rail drive 
belt
Inspect belt. Refer to the Tips 
section (5.3.5). 
S24 Canopy is clouded. Use of alcohol or hand-
disinfectants
Replace canopy. 
S25 The radiant heater doors do 
not close completely when the 
canopy is lowered.
Heater door top seal or 
bottom seal interferes with 
the doors.
Move or replace the seal.
Heater door arm on spring 
spool assembly is stuck.
Replace the heater door spring 
spool assembly.
Heater door spring spool 
assembly pins are 
touching the heater door 
cable.
Straighten pins away from the 
spring spool and cable.
ID Symptom Possible Cause(s) Action(s)