LAARS Heating Systems
Page 74
code Description
Lockout
or Hold
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
tolerance
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 Pressure Sensor for correct operation.
4. Replace the Pressure sensor.
5. if previous steps are correct and fault persists,
replace 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 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 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
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.
