Service manual

SERVICING
54
Testing Honeywell Smart Valve Systems
The ignition control module is a combination electronic and
electromechanical device and is not field repairable. Com-
plete unit must be replaced.
With Power ON:
WARNING
LINE VOLTAGE NOW PRESENT.
Furnace thermostat calling for heat (4 to 5 second preheat
time).
1. Check for 230 volts from L1 terminal of control module
to L2. No voltage - check wire connections, continuity,
etc.
2. Check for 24 volts at C" or X terminals on control board.
3. Voltage Present - check for voltage (24 VAC) between
terminals 1 & 3 on gas valve (R-29 & GY-30). No volt-
age - replace Control board.
Note: Voltage to ignitor should read 24 volts.
4. Main burner will light only after pilot has proved flame.
30 seconds after main burner lights check for voltage
between "heat" terminal and "neutral terminals" on
board. No voltage - replace Control board.
DSI Direct Spark Ignition Systems
NORMAL SEQUENCE OF OPERATION (DSI Direct
Spark Ignition System)
1. Thermostat calls for heat by energizing "W". The con-
trol checks the pressure switch for open condition. If
the pressure switch is closed the control will flash code
"3" and wait for the pressure switch to open.
2. The induced draft motor is energized and the control
flashes code "2" and waits for the pressure switch to
close. Once the pressure switch is closed, the LED stops
flashing and the control begins timing the 15 second
pre-purge.
3
2
1
6
54
9
8
7
12
11
10
L2 L2 L2
L2
COOL HEAT
UNUSED
L1
L1 D1
FS
Diagnostic LED
Blower Off Delay Settings
Transformer
speed up
DSI Control Board
3. The control energizes the spark igniter and gas valve
for 7 seconds. If flame is established, the control goes
into a 30 second heat on delay.
4. The indoor blower is energized at the heat speed after
a 30 second on delay.
5. The control monitors the safety circuit inputs, flame, and
thermostat during operation.
6. When the thermostat is satisfied, the gas valve is de-
energized 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 ther-
mostat call for heat ends.
Testing Direct Spark Ignition (DSI) systems
Furnace thermostat calling for heat (15 second prepurge
time and 7 second trial for ignition).
1. Check for 230 volts from L1 terminal of control module
to L2. No voltage - check wire connections, continuity,
etc.
2. Check for 24 volts at "R to C" thermostat terminals. No
voltage - check 3 amp automotive type fuse on control
board. A blow fuse would indicate a short in the 24 volt
circuit (thermostat or limit circuit).
3. Voltage Present - check for voltage (24 VAC) between
terminals 1 & 3 on gas valve (R-29 & GY-30). No volt-
age - replace Control board.
Diagnostics Flash Codes
LED Steady On Control is OK in standby, heat, cool, or
fan only modes.
LED Steady Off Internal control fault or no power.
1 Flash Lockout due to failed ignition or flame
dropouts.
2 Flashes Pressure switch is open with induced
draft motor energized.
3 Flashes Pressure switch is stuck closed with in-
duced draft motor de-energized.
4 Flashes Limit switch is open (primary, auxiliary,
or roll out).
5 Flashes Flame detected with gas valve closed.
6 Flashes Compressor output delayed from short
cycle timer.
7 Flashes Low flame sense current. Control will
flash 7-times while continuing normal
operation.
8 Flashes Lock out due to five consecutive limit
trips within a single call for heat. Resets
in 1/2 hour.
NOTE: The flash rate is 0.25 seconds on, 0.25 seconds
off, with a 2 second pause between codes.