Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 - Manual (Page 60)

60
Table 35 — IGC Board LED Alarm Codes
LEGEND NOTES:
1. There is a 3-second pause between alarm code displays.
2. If more than one alarm code exists, all applicable alarm codes will be
displayed in numerical sequence.
3. Alarm codes on the IGC will be lost if power to the unit is interrupted.
EconoMi$er IV Troubleshooting
ECONOMI$ER IV PREPARATION — This procedure is
used to prepare the EconoMi$er IV for troubleshooting. No
troubleshooting or testing is done by performing the following
procedure.
NOTE: This procedure requires a 9-v battery, 1.2 kilo-ohm
resistor, and a 5.6 kilo-ohm resistor which are not supplied
with the EconoMi$er IV.
1. Disconnect power at TR and TR1. All LEDs should be
off. Exhaust fan contacts should be open.
2. Disconnect device at P and P1.
3. Jumper P to P1.
4. Disconnect wires at T and T1. Place 5.6 kilo-ohm resistor
across T and T1.
5. Jumper TR to 1.
6. Jumper TR to N.
7. If connected, remove sensor from terminals S
O
and +.
Connect 1.2 kilo-ohm 4074EJM checkout resistor across
terminals S
O
and +.
8. Put 620-ohm resistor across terminals S
R
and +.
9. Set minimum position, DCV set point, and exhaust
potentiometers fully CCW (counterclockwise).
10. Set DCV maximum position potentiometer fully CW
(clockwise).
11. Set enthalpy potentiometer to D.
12. Apply power (24 vac) to terminals TR and TR1.
DIFFERENTIAL ENTHALPY — To check differential
enthalpy:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Place 620-ohm resistor across S
O
and +.
3. Place 1.2 kilo-ohm resistor across S
R
and +. The Free
Cool LED should be lit.
4. Remove 620-ohm resistor across S
O
and +. The Free
Cool LED should turn off.
5. Return EconoMi$er IV settings and wiring to normal
after completing troubleshooting.
SINGLE ENTHALPY — To check single enthalpy:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Set the enthalpy potentiometer to A (fully CCW). The
Free Cool LED should be lit.
3. Set the enthalpy potentiometer to D (fully CW). The Free
Cool LED should turn off.
4. Return EconoMi$er IV settings and wiring to normal
after completing troubleshooting.
LED
FLASH
CODE
DESCRIPTION
ACTION TAKEN BY
CONTROL
RESET METHOD PROBABLE CAUSE
On Normal Operation — — —
Off Hardware Failure No gas heating. — Loss of power to the IGC. Check 5 amp fuse on IGC,
power to unit, 24V circuit breaker, transformer, and
wiring to the IGC.
1 Flash Indoor Fan On/Off Delay
Modified 5 seconds subtracted from
On delay.
5 seconds added to Off
delay (3 min max). Power reset. High temperature limit switch opens during heat
exchanger warm-up period before fan-on delay
expires.
High temperature limit switch opens within
10 minutes of heat call (W) Off.
See Limit Switch Fault.
2 Flashes Limit Switch Fault Gas valve and igniter Off.
Indoor fan and inducer On. Limit switch closed, or
heat call (W) Off. High temperature limit switch is open. Check the oper-
ation of the indoor (evaporator) fan motor. Ensure that
the supply-air temperature rise is within the range on
the unit nameplate. Check wiring and limit switch
operation.
3 Flashes Flame Sense Fault Indoor fan and inducer On. Flame sense normal.
Power reset for LED reset. The IGC sensed a flame when the gas valve should be
closed. Check wiring, flame sensor, and gas valve
operation.
4 Flashes Four Consecutive Limit
Switch Fault
No gas heating. Heat call (W) Off.
Power reset for LED reset. 4 consecutive limit switch faults within a single call for
heat. See Limit Switch Fault.
5 Flashes Ignition Fault No gas heating. Heat call (W) Off.
Power reset for LED reset. Unit unsuccessfully attempted ignition for 15 minutes.
Check igniter and flame sensor electrode spacing,
gaps, etc. Check flame sense and igniter wiring. Check
gas valve operation and gas supply.
6 Flashes Induced Draft Motor Fault If heat off: no gas heating.
If heat on: gas valve Off and
inducer On. Inducer sense normal, or
heat call (W) Off. Inducer sense On when heat call Off, or inducer sense
Off when heat call On. Check wiring, voltage, and
operation of IGC motor. Check speed sensor wiring to
IGC.
7 Flashes Rollout Switch Lockout Gas valve and igniter Off.
Indoor fan and inducer On. Power reset. Rollout switch has opened. Check gas valve opera-
tion. Check induced-draft blower wheel is properly
secured to motor shaft.
8 Flashes Internal Control Lockout No gas heating. Power reset. IGC has sensed internal hardware or software error. If
fault is not cleared by resetting 24 v power, replace the
IGC.
9 Flashes Temporary Software Lockout No gas heating. 1 hour auto reset, or
power reset. Electrical interference is disrupting the IGC software.
IGC — Integrated Gas Unit Control
LED — Light-Emitting Diode
IMPORTANT: Be sure to record the positions of all poten-
tiometers before starting troubleshooting.