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SYSTEM OPERATION
8
Terminal
Label
230VAC Line 1 Input (x2)
L1
230VAC Line 2 Input (x4)
L2
Indoor Blower Heat Speed
HEAT
Indoor Blower Cool Speed
COOL
Induced Drafter Blower Output
DI
Unused/Motor Speed Park Terminals (x2) UNUSED
Flame Sensor
FS
Continuous Fan (G) / Economizer
ECON
Spark Igniter Output
SPARK
Table 2: PCBAG123 Single Stage Control Terminal
Definitions
Period
Timing
Pre-Purge
15 Seconds
Inter-Purge
15 Seconds
Post Purge
29 Seconds
Trial-for-Ignition (TFI)
7 Seconds
Flame Stabilization Period
10 Seconds
Heat ON Delay
30 Seconds
Heat OFF Delay
Selectable 120, 135
or 150 Seconds
Cool ON Delay
7 Seconds
Cool OFF Delay
60 Seconds
Ignition Attempts
3 Attempts
Recycles Infinite
4 Recycles
(5 Flame Losses)
Automatic Restart
60 Minutes
Compressor Short Cycle Delay 3 Minutes
Table 3: PCBAG123 Single Stage Control Timings
System Status
LED Flashes
Normal
On
Internal Fault/Gas Valve Fault
Off
Ignition Lockout
1
Pressure Switch Stuck Closed
2
Pressure Switch Stuck Open
3
Open High Temperature Limit
4
Flame Detected with Gas Valve De-Energized
5
Compressor Short Cycle Delay Active
6
Table 4: PCBAG123 Single Stage Control LED
Status Codes
PCBAG127 IGNITION CONTROL
SEQUENCE OF OPERATION (TWO STAGE
CONTROL)
Heating Operation: Low Stage Heat
1. Thermostat type is set to two-stage.
2. Thermostat “W1” input initiates low stage heating.
3. Induced draft blower is energized at high speed for
the pre-purge period. Pre-purge timer begins after
control recognizes pressure switch has closed.
4. Trial-for-ignition period begins after pre-purge period
expires. Low and high stage gas valves are energized
along with the igniter for trial-for-ignition period. Igniter
is de-energized when flame is detected.
5. Flame is achieved and detected during trial-for-ignition
period. Flame stabilization period begins when flame
is detected.
6. De-energize high stage gas valve and switch induced
draft blower to low speed within five seconds of flame
detection.
7. Air circulating blower is energized at low heat speed
after heat ON delay time expires. Heat ON delay timer
begins when flame is detected.
8.
Control monitors thermostat, flame, limit, and pressure
switch inputs during low stage heating.
9. Thermostat “W1” input is removed.
10. Low stage gas valve is de-energized.
11. Induced draft blower remains energized at low speed
for post purge period.
12. Air circulating blower remains energized at low heat
speed for heat OFF delay. Heat OFF delay begins
when “W1” input is removed.
13. Control returns to Standby and awaits next thermostat
request.
Heating Operation: High Stage Heat
1. Thermostat type is set to two-stage.
2. Thermostat “W1” and “W2” inputs initiate high stage
heating.
3. Induced draft blower is energized at high speed for
the pre-purge period. Pre-purge timer begins after
control recognizes pressure switch has closed.
4. Trial-for-ignition period begins after pre-purge period
expires. Low and high stage gas valves are energized
along with the igniter for trial-for-ignition period. Igniter
is de-energized when flame is detected.
5. Flame is achieved and detected during trial-for-ignition
period. Flame stabilization period begins when flame
is detected.
6. Gas valve and induced draft blower remain at high
stage and high speed.
7. Air circulating blower is energized at high heat speed
after heat ON delay time expires. Heat ON delay timer
begins when flame is detected.
8.
Control monitors thermostat, flame, limit, and pressure
switch inputs during high stage heating.
9. Thermostat “W1” and “W2” inputs are removed.
10. High and low stage gas valves are de-energized.