Cambridge Air Solutions
16
SA-Series Technical Manual
warm-up, the burner will light. Allow 15 seconds for
the low fire start to time out.
5. Monitor the discharge temperature and flame signal.
Subtract temperature from step 1 above from this
reading to determine temperature rise. If minimum
fire temperature rise is above 20ºF and flame signal is
above 2.0 microamps DC, proceed to step 7.
6. Remove the cap (A) exposing the minimum fire
adjusting screw. Turn the adjusting screw (B) to obtain
the desired minimum fire setting.
7. Replace the cap (A).
8. Turn blower and burner service switches to the “OFF”
position.
9. Reconnect the wire to terminal #8 on the amplifier.
10. When performing start-up proceed to next step,
otherwise perform Final Heater Preparation (page 17).
CALIBRATION CHECK
The discharge temperature control system has been
calibrated at the factory to the specified airflow, static
pressure, and temperature rise. The actual operating
conditions may require minor adjustments to the control
settings to ensure the heater functions within the operating
parameters of its listing.
1. Remove the cover of the Discharge Air Temperature
Sampling Box. Refer to the Heater Configuration
(page 5) for the Discharge Air Temperature Box
location, and the Individual Component Description
Section (page 39) for additional information. Install
a thermocouple in the grommet inside the Discharge
Air Temperature Sampling Box, and then reinstall the
cover. Route the thermocouple wire to a meter located
outside of the unit.
2. The discharge temperature should match the
temperature shown on the MAX dial located on the
amplifier with a resistor of 7,500 ±250
Ω
connected
between terminals 21 and 22. The dial should be set
to 160°F.
IMPORTANT
The heater access doors must be closed for the remaining
portion of this test.
3. Turn the blower and burner service switches to the
“LOCAL” position. After a delay for prepurge and
igniter warm-up, the burner will light. Allow 15
seconds for the low fire start to time out.
4. Monitor the discharge temperature until it stabilizes.
Do not rush through this step.
5. The discharge temperature should be 160 +0/-
5°F. If the discharge temperature complies with
this requirement, no calibration is required. If the
discharge temperature does not equal the expected
value, proceed to Calibration Procedure (page 17).
6. For CE-Smart
TM
Controls remove the resistor
on terminals 21 and 22 and connect the Space
Temperature Selector (STS).
7. When performing a start-up proceed to the next step,
otherwise perform Final Heater Preparation (page 17).
GAS VALVE LEAK CHECK
All heaters should be evaluated for the gas tightness of the
gas valve seat. This evaluation must be performed at least
once per year.
1. Connect a 0 to 10 inches water column (" WC)
manometer to the 1/8" NPT tapped fitting directly
before the manual shut-off valve located just prior to
the burner for the purpose of monitoring an increase
in pressure, and verify the manometer is properly
zeroed.
2. Close the manual burner shut-off valve and, with
supply gas connected, wait 30 seconds to read the
manometer. If reading is greater than 0" WC, replace
the gas valve and retest. If reading is 0" WC, remove
manometer and install pipe plug.
3. When performing start-up proceed to next step,
otherwise perform Final Heater Preparation (page 17).
GAS TRAIN LEAK CHECK
1. Remove the wire from terminal #3 on the amplifier.
This will drive the modulating valve to full open.
2. Turn the blower service switch to the “LOCAL”
position. Blower motor will start after the motorized
damper (optional) opens.
