Goodman [A/G]PG, Service Instructions Manual

SERVICING

51

6. When the thermostat is satisfied, the gas valve is de-ener-

gized and the induced draft blower remains on for a 29
second post purge. The indoor blower remains on for the
selected heat blower off delay (90, 120, or 150 seconds).
Indoor blower off timing begins when thermostat call for
heat ends.

Testing Direct Spark Ignition (DSI) systems

Thermostat calling for heat (15 second prepurge time and 7
second trial for ignition).

1. Check for 230 VAC from L1 terminal of control module to

L2.  No voltage - check wire connections, continuity, etc.

2. Check for 24 VAC at "R" to "C" thermostat terminals.

a.

No voltage - check 3 amp automotive type fuse on
control board. A blown fuse would indicate a short in
the 24 VAC circuit (thermostat or limit circuit).

b.

Voltage Present - check limit, auxiliary limit and
rollout (S-300, S-301 and S-302). If limit, auxiliary
limit and rollout are closed, then check for 24 VAC
at the gas valve terminals.

No 24 VAC at gas valve - replace Control board.

Status Light

Equipment Status

Check

On

Normal Operation

Off

No Power or

Internal Control Fault

Check Input Power, 

Check Fuse on Control, 

Replace Control

1 Blink

Ignition Failure,

Open Rollout Switch,  

or Open Aux. Limit 

Switch

Check Gas Flow,

Check Gas Pressure, 

Check Gas Valve,

Check Flame Sensor,
Check Flame Rollout,

Check Aux. Limit.

2 Blinks

Pressure Switch Open Check Pressure Switch

3 Blinks

Pressure Switch 

Closed

Check Pressure Switch

4 Blinks

Open Main Limit 

Switch

Main Limit Switch Open

5 Blinks

False Flame Sensed

Sticking Gas Valve

6 Blinks

Compressor Output 

Delay

3 Minute Compressor 

Anti-Cycle Timer

B1809918 Ignition Board Fault Codes

NOTE: 

 The flash rate is 0.25 seconds on, 0.25 seconds off,

with a 2-second pause between codes.

S-314 CHECKING FLAME SENSOR

A flame sensing device is used in conjunction with the ignition
control module to prove combustion.  If a microamp signal is
not present the control will de-energize the gas valve and "re-
try" for ignition or lockout.

DSI Direct Spark Ignition Systems

1. Disconnect the flame sensor wire from terminal FS on the

ignition control module.

Flame
Sensor

Flame Sensor

2. Connect a microamp meter in series with this wire and the

terminal FS on the ignition control.

3. Be sure the negative side of the meter is to the wire and the

positive of the meter is to terminal FS on the ignition con-
trol.

4. Turn on Power.

Line Voltage now present.

5. With Power ON, place the unit into a heating cycle.

6. As soon as flame is established a microamp reading should

be evident once proof of flame (microamp reading) is estab-
lished, the direct spark ignitor will be de-energized.

7. The microamp reading should be 4 - 6 microamps.

8. If the microamp current is less than 0.5 microamp the con-

trol will lockout and flash a code of 1 flash after attempting
to reestablish flame sense.

9. If the microamp reading is less than the minimum speci-

fied, check for high resistance wiring connections, the dis-
tance (3/16") between the sensor and burner, flame sensor
connections, dirty flame sensor or poor grounding.

10. If no reading, check for continuity on all components and if

good - replace ignition control module.

NOTE:  

Contaminated fuel or combustion air can create a nearly

invisible coating on the flame sensor.  This coating works as
an insulator causing a loss in the flame sense signal.  If this
situation occurs the flame sensor must be cleaned with steel
wool. Do not use sand paper, the silicone in sand paper will
further contaminate the sensor.