LAARS NeoTherm NTV (Sizes 150–850 MBTU/h) - Install and Operating Manual - Manual (Page 86)

Page 82 LAARS Heating Systems
132 Fan speed failed during run H 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.
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 on when it should be off.
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 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.
156 Combustion pressure and flame
On
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.
157 Combustion pressure and flame
Off
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.
158 Main valve On L 1. Check the main valve terminal wiring and correct any errors.
2. Reset and sequence the module. If fault persists, replace the
module.
Code Description L or H Procedure