Cambridge Air Solutions
18
SA-Series Technical Manual
a. Turn the burner service switch to the “OFF”
position and allow the Discharge Air
Temperature Sampling Box time to cool.
b. Turn blower service switch to “OFF” position.
c. Open the control enclosure door.
d. Remove the access cover from the Discharge
Air Temperature Sampling Box and remove the
two mounting screws from the DTS. Refer to the
Individual Component Description Section (page
38-40) for additional information.
e. Carefully remove the DTS from the sampling
box, turn it over and adjust the DTS calibration
potentiometer shown in the drawing. To raise the
discharge temperature, adjust the potentiometer
90˚ counterclockwise.
f. Carefully reinstall the DTS. Replace the
Discharge Air Temperature Sampling Box cover,
and close the unit access doors.
g. Turn the blower and burner service switches to
the “LOCAL” position. After a delay for the
prepurge and igniter warm-up, the burner will
light.
h. Wait for the discharge temperature and manifold
pressure to stabilize. Do not rush this step.
i. Repeat steps 2 through 4 until manifold pressure
and discharge temperature comply with guidelines
of Calibration Check procedure step 5 (page 16).
j. Reinstall the amplifier that was removed in step 1.
MAINTENANCE INSTRUCTIONS
BELT TENSIONING (SA350 ONLY)
Using a Browning Belt Tension Checker and a straight
edge, verify proper belt tension to a center span
deflection of 1/4" for 2-3 lbs. for new belts or 1-2 lbs.
for used belts.
Periodic belt adjustments may be required. Indications
of loose belts include barking or squealing when blower
starts.
BLOWER CLEANING
The blower wheel should be examined for accumulation
of dust on the blades. These surfaces must be kept clean.
Dirt accumulation will result in significant air flow
reduction and/or possible imbalance of the blower wheel.
CAUTION:
Prolonged imbalance can result in catastrophic
failure of the blower wheel and other related
components.
BURNER CLEANING
The Cambridge Air Solutions burner is for the most part
self-cleaning. However, if the application is extremely
dirty or dusty, it may become necessary to periodically
clean the burner. Remove and clean the burner in
accordance with the following recommended procedures:
1. Turn off the disconnect switch (by others). Close the
manual gas supply shut-off valve.
2. Loosen the union in the gas train.
3. Disconnect the ignition cable from the burner and
remove the flame rod and the igniter.
4. Examine the flame rod ceramic for cracks and replace
if necessary. Clean the flame rod element with emery
cloth to remove oxidation.
5. Remove fasteners that secure burner to housing. The
burner will then be free to slide out.
6. Clean burner by back-flushing using high pressure
air (40-80 PSI). Continue back flushing until dust
particles are completely expelled from burner.
7. Reinstall burner using above steps in reverse order.
GAS TRAIN LEAK CHECK
Periodically check the gas control assembly, internal and
external piping for leaks. Refer to the Gas Train Leak
Check procedure (page 16). All relief vents on the gas
controls should be checked for blockage (gas pressure
regulators and pressure switches).
