S-Series Technical Manual 27 Cambridge Engineering, Inc.
step, otherwise perform Final Heater Preparation
(page 29).
8. 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 con-
trol settings to ensure the heater functions within the
operating parameters of its listing.
a. Remove the cover of the discharge air temperature
sampling box. Refer to the Heater Configuration
(page 4) for the discharge air temperature sam-
pling box location, and the Individual Component
Description Section (page 67) for additional infor-
mation. 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.
b. On EDL control systems, the discharge tempera-
ture should match the temperature shown on the
dial located on the amplifier. The dial should be set
to 160°F.
On EDSM and EDSM/TP control systems, the
discharge temperature should match the tempera-
ture shown on the MAX dial on the amplifier when
the Space Temperature Selector (STS) is set to its
highest setting. If the space temperature is warm,
a test resistance of 7,500 ±250 Ω should be con-
nected in the circuit in place of the STS. The MAX
dial on the amplifier should be set to 160°F.
On EDR control systems, jumper terminals 20 and
22 and turn the dial on the remote heat adjust RHA
to its highest setting to utilize the full temperature
range of the control system. On heaters with a
single temperature selection dial on the face of the
control (Maxitrol part number TD114), set the dial
to 90°F and verify that the override temperature
selector dial, which is visible from the top of the
control, is set at 40°F. The combination of these
two settings should control the discharge tempera-
ture to 130°F. On heaters with dual temperature
selection dials on the face of the control, set the
Space Heat dial to 160°F.
IMPORTANT
The heater access doors must be closed for the re-
maining portion of this test.
c. Turn the burner service switch 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.
d. Monitor the discharge temperature until it stabi-
lizes. Do not rush through this step.
e. The discharge temperature should be 130 ± 3°F for
heaters setup for 130°F, or 160 +0/-5°F for heat-
ers setup for 160°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
Procedures (page 29).
f. Remove any jumpers that were installed previously.
g. When performing a start-up proceed to the next
step, otherwise perform Final Heater Preparation
(page 29).
9. GAS TRAIN LEAK CHECK
a. On EDL, EDR, EDSM, and EDSM/TP control
systems, remove the wire from terminal #3 on the
amplifier. This will drive the modulating valve to
full open.
b. Turn the blower service switch to the “LOCAL”
position. Blower motor will start after the motor-
ized discharge damper opens.
c. Turn the burner service switch 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.
d. With the burner operating, spray the complete gas
train with leak detector solution, checking all pipe
connections and plugs.
mCAUTION:
Do not allow leak detector solution to come in
contact with electrical components.
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