LAARS NeoTherm NTV (Sizes 399-850 MBTU/h) - Service Manual - Manual (Page 104)

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Service Manual - NeoTherm 500
Appendix 1 - Error Codes (continued)
Code Description L or H Procedure
97 Internal fault: A2D mismatch. L Internal Fault.
1. Reset module.
2. If fault repeats, replace module.
98 Internal fault: Exceeded VSNSR voltage
tolerance
L Internal Fault.
1. Reset module.
2. If fault repeats, replace module.
99 Internal fault: Exceeded 28V voltage toler-
ance
L Internal Fault.
1. Reset module.
2. If fault repeats, replace module.
100 Pressure sensor fault H 1. Verify the pressure sensor is a 4-20 ma source.
2. Check wiring and correct any possible errors.
3. Test the pressure sensor for correct operation.
4. Replace the pressure sensor.
5. If previous steps are correct and fault persists, re-
place the module.
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 cor-
rect terminal.
3. Make sure the flame and ground 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 (Main Flame Establish-
ing Period)
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 and 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 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.
App1
cont.