Laars NEOTHERM NTH Series, Installation And Operation Instructions Manual

Page: 78 / 84

Page 78
LAARS Heating Systems
105 Flame detected out of sequence H or L
1. Check that flame is not present in the combustion chamber.
Correct any errors.
2. Make sure that the flame detector is wired to the correct
terminal.
3. Make sure the F & G wires are protected from stray noise
pickup.
4. Reset and sequence the module. If code reappears, replace
the flame detector.
5. Reset and sequence the module. If code reappears, replace
the module.
106 Flame lost in MFEP L 1. Check the 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.
107 Flame lost early in run L
108 Flame lost in run L
109 Ignition failed L
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
113 Flame circuit timeout L
Flame sensed during initiate or off cycle. Produces a Hold for
240 seconds. If still present after 240 seconds, system will
lockout.
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
128 Fan speed failed during prepurge H or L
129 Fan speed failed during preignition H or L
130 Fan speed failed during ignition H or L
131 Fan movement detected during standby H
132 Fan speed failed during run H
137 ILK (Interlock) failed to close H 1. Check wiring and correct any possible shorts.
2. Check Interlock (ILK) switches to assure proper function.
3. Verify voltage through the interlock string to the interlock input
with a voltmeter.
4. If steps 1-3 are correct and the fault persists, replace the
module.
149 Flame detected H or L
Create a Hold if a flame is detected during Safe Start check up
to Flame Establishing period.
150 Flame not detected H Sequence returns to standby and restarts sequence at the
beginning of Purge after the HF switch opens if flame detected
during Safe Start check up to Flame Establishing period.
154 Purge Fan switch On H or L
1. Purge fan switch is off when it should be on.
2. Check wiring and correct any errors.
3. Inspect the Purge Fan switch J6 terminal 3 and its
connections. Make sure the switch is working correctly and is
not jumpered or welded.
4. Reset and sequence the relay module.
5. If the fault persists, replace the relay module.
155
Purge fan switch Off
H or L