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5. Set the outdoor-air thermostat (OAT), located in the econo-
mizer section of the unit to 75 F.
6. If the outdoor temperature is below 75 F, the econo-
mizer will control the mixed air with the mixed-air sen-
sor. If the outdoor air is above 75 F, place a jumper around
the contacts of the OAT.
7. Jumper terminal T to terminal T1 on the module (see
Fig. 18). The economizer will go to the full open position.
The outdoor-air damper will go to the full open posi-
tion, and the return-air damper will go to the full closed
position.
8. Adjust mechanical linkage, if necessary, for correct po-
sitioning. If may be necessary to remove the filters to
adjust the linkage.
9. Remove the jumper from around the contacts of the OAT
if installed in Step 6. Remove the jumper from termi-
nals T and T1 installed in Step 7.
10. If the Cooling mode was simulated to operate the unit
in Step 4, remove the jumper and reconnect the ther-
mostat wires to terminals Y1 and Y2.
Table 8 — Economizer Checkout Procedures
TEST PROCEDURE
RESULTS
A. Disconnect power at TR and
TR1. Disconnect jumper be-
tween P and P1. See Fig. 18.
B. Jumper TR to 1.
C. Jumper T1 to T.
D. Disconnect outdoor-air ther-
mostat connections from S
O
and +. Factory-installed
800 ohm resistor should re-
main connected to S
R
and +.
E. Reconnect power to terminals
TR and TR1.
1. LED (light-emitting diode)
should be off.
2. Motor is in closed position.
TEST PROCEDURE
RESULTS
Disconnect factory-installed re-
sistor from terminals S
R
and +.
1. LED (light-emitting diode)
should be on.
2. Motor drives toward open.
Table 9 — High and Low Outdoor-Air Temperature
TEST PROCEDURE
RESULTS
A. Reconnect factory-installed
800 ohm resistor between ter-
minals S
R
and +.
B. Connect 1200 ohm checkout
resistor between terminals S
O
and +.
C. Turn set point potentiometer
to position A.
Low outdoor-air temperature
test results:
1. LED (light-emitting diode)
should be on.
2. Motor drives toward open.
D. Turn set point potentiometer
to position D.
E. Disconnect 1200 ohm check-
out resistor.
High outdoor-air temperature
test results:
1. LED should be off.
2. Motor drives toward closed.
Power Failure —
Dampers have a spring return. In event
of power failure, dampers will return to fully closed position
until power is restored. Do not manually operate damper
motor.
Refrigerant Charge —
Amount of refrigerant charge
is listed on unit nameplate and in Table 1. Refer to Carrier
GTAC II; Module 5; Charging, Recovery, Recycling, and Rec-
lamation section for charging methods and procedures.
Unit panels must be in place when unit is operating dur-
ing charging procedure.
NO CHARGE — Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of
refrigerant (refer to Table 1).
LOW CHARGE COOLING — Using appropriate cooling
charging chart (see Fig. 33-35), add refrigerant until condi-
tions of the chart are met. Note that charging charts are dif-
ferent from those normally used. Charts are based on charg-
ing units to correct superheat for various operating conditions.
An accurate pressure gage and temperature sensing device
are required. Connect temperature sensing device to service
port on suction line and insulate it so that outdoor ambient
temperature does not affect reading. Indoor-air cfm must be
within normal operating range of unit.
TO USE COOLING CHARGING CHART — Take outdoor
ambient temperature and read the suction pressure gage. Re-
fer to appropriate chart to determine correct suction tem-
perature. If suction temperature is high, add refrigerant. If
suction temperature is low, carefully reclaim some of the charge.
Recheck suction pressure as charge is adjusted.
Pilot Light —
If pilots do not light as described in Gas
Heat section on page 17, be sure that pilot orifice is not ob-
structed, then check for spark ignitor malfunctions as fol-
lows:
1. Shut off control supply power to ignitor control pack (ICP).
2. Check that spark gap is
1
⁄
8
in.
6
1
⁄
32
inch.
3. Check that ICP is securely grounded.
4. Check that high-voltage lead is securely connected be-
tween ICP and electrode body.
5. Restore power to ICP. Check that 24 v is supplied
to terminal TH of ICP.
6. Check unit label diagram for correct terminal usage if any
wires are removed.
Fig. 33 — Cooling Charging Chart, 48HJ015
21
Summary of Contents for 48EJ
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Page 25: ...Fig 38 Typical Wiring Schematic 48HJ025 Shown cont 25 ...
Page 26: ...Fig 39 Typical Component Arrangement 48HJ025 Shown 26 ...
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