Cambridge Air Solutions
88
S-Series Technical Manual
TROUBLESHOOTING INSTRUCTIONS
TROUBLESHOOTING GUIDE
Problem
Possible Cause
Corrective Action
IX. MODULATING
VALVE DOES NOT
MODULATE;
CONTINUOUS
LOW FIRE
(Continued)
5. Space Temperature Selector
(T244 or TS244/TD244)
a) Short in sensor circuit
a) Replace the sensor if the resistance
measure is less than 5,000 Ω for the T244
or 3,500 Ω for the S244 and 1,950 Ω for
the TD244.
6. Remote Heat Adjust
(TD114 or CEI 4175-0-960)
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. Multi-Functional PC Board
a) Terminal X has power
b) Defective board
a) Determine power source.
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 appropriate calibration procedure
(pages 60–62).
c) Replace amplifier.
3. Space Temperature Selector
(T244 or TS244/TD244)
a) Induced voltage in field wiring
a) Utilize shielded, twisted pair wiring.
4. Remote Heat Adjust
(TD114 or CEI 4175-0-960)
a) Induced voltage in field wiring
a) Utilize shielded, twisted pair wiring.