Laars NTH1000, Installation And Operation Instructions Manual, Page: 108 / 140

LAARS Heating Systems Page 104
Code Description L or
H
Procedure
108 Flame lost in run L 1. Check main valve wiring and operation -
correct any errors.
2. Check the fuel supply.
3. Check fuel pressure and repeat turndown tests.
4. Check ignition transformer electrode, flame
detector, flame detector siting or flame rod
position.
5. If steps 1 through 4 are correct and the fault
persists, replace the module.
109 Ignition failed L 1. Check main valve wiring and operation -
correct any errors.
2. Check the fuel supply.
3. Check fuel pressure and repeat turndown tests.
4. Check ignition transformer electrode, flame
detector, flame detector siting or flame rod
position.
5. If steps 1 through 4 are correct and the fault
persists, replace the module.
110 Ignition failure occurred H Hold time of recycle and hold option. Will not be
a lockout fault. Hold Only. Internal hardware test.
Not a lockout.
111 Flame current lower than weak
threshold
H Hold time of recycle and hold option. Will not be
a lockout fault. Hold Only. Internal hardware test.
Not a lockout.
113 Flame circuit timeout L Flame sensed during Initiate or off cycle, hold 240
seconds, if present after 240 seconds, system will
lockout.
119 Control Interaction Fault H Flap valve identifications configured incorrectly.
122 Lightoff rate proving failed L 1. Check wiring and correct any potential wiring
errors.
2. Check VFD’s (Variable-speed Fan Drive)
ability to change speeds.
3. Change the VFD
4. If the fault persists, replace the module.
123 Purge rate proving failed L 1. Check wiring and correct any potential wiring
errors.
2. Check VFD’s (Variable-speed Fan Drive)
ability to change speeds.
3. Change the VFD
4. If the fault persists, replace the module.
128 Fan speed failed during prepurge H or
L
1. Check wiring and correct any potential wiring
errors.
2. Check the VFDs (Variable-speed Fan Drive)
ability to change speeds.
3. Change the VFD
4. If the fault persists, replace the module.