Cambridge Air Solutions.
102
M-Series Technical Manual
Problem
Possible Cause
Corrective Action
IX. MODULATING
VALVE DOES NOT
MODULATE;
CONTINUOUS
LOW FIRE
(Continued)
5. Space Temperature Selector
(T244A or TS244A/TD244A)
a) Short in sensor circuit
a) Replace the sensor if the resistance
measure is less than 5,000 Ω for the
T244A or 3,500 Ω for the TS244A and
1,950 Ω for the TS244A.
6. Remote Heat Adjust
(TD114)
a) Open in the Remote Heat Adjust control
circuit
a) Replace the control if the resistance
measured at terminals 1 and 3 exceeds
12,000 Ω.
7. High Airflow Switch
a) Pressure drop across burner too high
b) Defective Airflow Switch
a) Measure pressure drop and adjust profile
damper.
b) Replace Airflow Switch.
8. Multi-Functional PC Board
a) Temp sensor wires not seated properly in
terminal block.
b) Defective board
a) Reinstall sensor wires.
b) Replace board.
X. ERRATIC OR
PULSATING FLAME
1. High Pressure Regulator
a) Vent undersized
b) Defective regulator
a) Enlarge vent piping size or reduce vent
piping length.
b) Replace regulator.
2. Amplifier
a) Hunting
b) Temperature control system out of
calibration
c) Defective amplifier
a) Adjust sensitivity control dial counter-
clockwise.
b) Perform
temperature control system
calibration.
c) Replace amplifier.
3. Space Temperature Selector
(T244A or TS244A/TD244A)
a) Induced voltage in field wiring
a) Utilize shielded, twisted pair wiring.
4. Remote Heat Adjust (TD114)
a) Induced voltage in field wiring
a) Utilize shielded, twisted pair wiring.
TROUBLESHOOTING GUIDE
