LAARS HP-M2 Series - Installation, Operation and Maintenance Instructions - Manual (Page 41)

H Series Page 41
SECTION 15.
Trouble Shooting
15A. S9301A Control Module
NORMAL SEQUENCE
FAILURE TO COMPLETE THIS CYCLE
Event
Control Funtion
Verified
Envent Confirmed
Light Event
Unconfirmed
Action for Diagnosis
A. Power switch on
Integrated boiler control (S9301A)
Green "POWER" light on. Note: If internal pump is running unit may be in lockout. Reset power switch.
1. No 120 VAC supply
1. Read voltage between black & white wires at back of (120 VAC) plug
2. Defective 24 VAC transformer
2. Read voltage between yellow wires at back of (VAC 24XFMR) plug
3. Defective S9301A module
3. Replace S9301A part #2400-224
B. Prepurge (if low limit or Thermostat calling) 2 - 17) secs)
1. Internal Pump Starts
Red "PURGE" light on. Note: If unit in purge mode without light, stack switch is not proving air flow.
1. Internal pump defective or air bound
1. Check for 120 VAC at module pins marked circulator (opposite brown and white)
2. Low limit (HW-only), operating control, safety limit, system pressure switch, stack switch
2. Defective low limit, operating control, safety limit or differential presssure switch
2. Jump control wires, one control at a time to identify open circuit control, no continuity.
3. Blower starts
3. Defective inducer blower
3. Check for 120 VAC at module pins marked inducer (opposite gray and white wires)
C. Igniter heats up and remains on (17 - 39 sec)
Igniter via S9301A
Red "IGNITER" light on Red "PURGE" light off Blower continues to run
Igniter does not heat up - look for heat up at igniter base
Check for 120 VAC at pins marked IGNR (blue wires) during igniter light "on"
D. Gas valve energized (37 - 43 secs)
Gas valve opens
Red "VALVE/FLAME" light on.
1. Stack switch does not confirm air flow. 2. Gas valve has short.
Check for 24 VAC between orange and yellow wires on gas valve when red "VALVE / FLAME" light is on
E. Ignitor off (39 sec) Gas valve energized (39 - 43+ sec)
Igniter, air & gas source
Igniter monitors flame via flame rectification to ground
Unit transfer to purge 12-15 secs after "valve / flame" light is on and repeats sequence
See trouble shooting section under "cross contamination" & "short cycling" in service manual
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