Carrier 48PG20-28 EconoMi$er IV Troubleshooting, IGC Board LED Alarm Codes, Flashes

Table 35 — IGC Board LED Alarm Codes

LED		ACTION TAKEN BY
FLASH	DESCRIPTION		RESET METHOD	PROBABLE CAUSE
		CONTROL
CODE
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	5 seconds subtracted from	Power reset.	High temperature limit switch opens during heat
	Modified	On delay.		exchanger warm-up period before fan-on delay
		5 seconds added to Off		expires.
		delay (3 min max).		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.	Limit switch closed, or	High temperature limit switch is open. Check the oper-
		Indoor fan and inducer On.	heat call (W) Off.	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.	The IGC sensed a flame when the gas valve should be
			Power reset for LED reset.	closed. Check wiring, flame sensor, and gas valve
				operation.
4 Flashes	Four Consecutive Limit	No gas heating.	Heat call (W) Off.	4 consecutive limit switch faults within a single call for
	Switch Fault		Power reset for LED reset.	heat. See Limit Switch Fault.
5 Flashes	Ignition Fault	No gas heating.	Heat call (W) Off.	Unit unsuccessfully attempted ignition for 15 minutes.
			Power reset for LED reset.	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.	Inducer sense normal, or	Inducer sense On when heat call Off, or inducer sense
		If heat on: gas valve Off and	heat call (W) Off.	Off when heat call On. Check wiring, voltage, and
		inducer On.		operation of IGC motor. Check speed sensor wiring to
				IGC.
7 Flashes	Rollout Switch Lockout	Gas valve and igniter Off.	Power reset.	Rollout switch has opened. Check gas valve opera-
		Indoor fan and inducer On.		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	Electrical interference is disrupting the IGC software.
			power reset.

LEGEND

IGC — Integrated Gas Unit Control

LED — Light-Emitting Diode

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.

IMPORTANT: Be sure to record the positions of all poten- tiometers before starting troubleshooting.

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 SO and +. Connect 1.2 kilo-ohm 4074EJM checkout resistor across terminals SO and +.

8.Put 620-ohm resistor across terminals SR 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 SO and +.

3.Place 1.2 kilo-ohm resistor across SR and +. The Free Cool LED should be lit.

4.Remove 620-ohm resistor across SO 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.

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