Troubleshooting
RT-SVX21AC-EN 77
• Fast Flash - 1/2 second on / 2 seconds off:
• Error Code: Communications failure
• Pulse Fl
ash:2 seconds on / 1/2 second
off:
• Error Code:
• 1 Flash: Actuator Fault
• 2 Flashes: CO
2
Sensor
• 3 Flashes: RA Humidity Sensor
• 4 Flashes: RA Temp Sensor
• 5 Flashes: OA Quality Sensor
• 6 Flashes: OA Humidity Sensor
• 7 Flashes: OA Temp Sensor
• 8 Flashes: MA Temp Sensor
• 9 Flashes: RAM Fault
• 10 Flashes: ROM Fault
• 11 Flashes: EEPROM Fault
Electromechanical Control
The IGN has the ability to provide the service personnel
with some unit diagnostics and system status information.
Before turning the main power disconnect
switch “Off”,
follow the steps
below to check the Ignition Module (IGN).
To prevent injury or death from electrocution, it is the
responsibility of the technician to recogniz
e this hazard
and use extreme care when performing service
procedures with the electrical power energized.
1. Verify LED on face of the phase monitor is green. If LED
is red,
correct supply po
wer fault.
2. Verify that the LED on the IGN is burning continuously.
If the LE
D is lit, go to Step 4.
3. If the LED is not lit, verify th
at 24 Vac is pr
esent between
R and B. If the LED is not lit and 24 Vac is present
replace the IGN. If 24 Vac is not present, check
transformer (TNS1). Proceed to Step 4 if necessary.
4. If no failures are indicated, use the TEST mode
pr
ocedures described in th
e “Unit Start-Up” section or
thermostat to start the unit. This procedure will allow
you to check all of the external controls (relays,
contactors, etc) and the IGN.
5. Test the system through all of the available modes, and
v
erif
y operation of all outputs, controls, and modes.
Refer to the sequence of operations for each mode, to
assist in verifying proper operation. Make the
necessary repairs and proceed to Step 6 and Step 7.
6. If no abnormal operating conditions appear in the test
mode, exit
the test mode by turning the power “Off” at
th
e main power disconnect switch and removing the
test mode connections.
7. Refer to the individual component test procedures if
o
ther co
mponents are suspect.
Heating Failure
Verify Heat Failure by Ignition Module (IGN) LED indicator:
• OFF: No Power or Failure
• ON: Normal
• Slow Flash: Normal, Heat Call
• Fast Flash: Error Code:
1 Flash: No Communication
2 Flashes: System Lockout
3 Flashes: Pressure Switch Fail
4 Flashes: TC01 or TC02 Open
5 Flashes: Flame w/o Gas Valve
6 Flashes: Flame Rollout Open
Cooling Failure
• Cooling and heating set point (slide pot) on the
thermostat has failed.
• CC1 or CC2 24 Vac control circuit has opened, check
CC1 and CC2 coils, and any o
f the controls below that
apply to the unit (HPC1, HPC2, LPC1, LPC2, Frostat™).
Resetting Cooling and Ignition Lockouts
Cooling Failures and Ignition Lockouts are reset in an
identical manner. Method 1 explains resetting the system
from the space; Method 2 explains resetting the system at
the unit.
Method 1
To reset the system from the space, turn the “Mode”
selection switch at the thermostat to the “Off” position.
After approximately 30 seconds, turn the “Mode”
selection switch to the desired mode, i.e. Heat, Cool or
Auto.
Method 2
To reset the system at the unit, cycle the unit power by
turning the disconnect switch “Off” and then “On”.
WARNING
Live Electrical Components!
Failure to follow all electrical safety precautions when
exposed to live electrical components could result in
death or serious injury. When necessary to work with
live electrical components, have a qualified licensed
electrician or other individual who has been properly
trained in handling live electrical components perform
these tasks.
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