Carrier 50FC 04 Series Service And Maintenance Instructions page 120

PRESSURES
Refrigerant Suction
Refrigerant Discharge
Verify Refrigerant Charge using Charging Charts.
GENERAL
Economizer minimum vent and changeover settings to job requirements (if equipped).
Verify smoke detector unit shutdown by utilizing magnet test.
®
IV. HUMIDI-MIZER SYSTEM START-UP
STEPS
1. Check UCB (Unit Control Board) for jumper 1, 2, 3 (Jumper 1, 2, 3 must be cut and open).
2. Open humidistat contacts.
3. Start unit In cooling (Close Y1).
OBSERVE AND RECORD
a. Suction pressure
b. Discharge pressure
c. Entering air temperature
d. Liquid line temperature at outlet or reheat coil
e. Confirm correct rotation for compressor.
f. Check for correct ramp-up of outdoor fan motor as condenser coil warms.
4. Switch unit to high-latent mode (sub-cooler) by closing humidistat with Y1 closed.
5. Check unit charge per charging chart.
OBSERVE
a. Reduction in suction pressure (5 to 7 psi expected).
b. Discharge pressure unchanged.
c. Liquid temperature drops to 50 to 55°F range.
d. LSV solenoid energized (valve closes).
6. Switch unit to dehumid (reheat) by opening Y1.
OBSERVE
a. Suction pressure increases to normal cooling level.
b. Discharge pressure decreases (35 to 50 psi). (Limited by head pressure control.)
c. Liquid temperature returns to normal cooling level.
d. LSV solenoid energized (valve closes).
e. DSV solenoid energized, valve opens.
7. With unit in dehumid mode close W1 compressor and outdoor fan stop; LSV and DSV solenoids de-energized.
8. Open W1 restore unit to dehumid mode.
9. Open humidistat input compressor and outdoor fan stop; LSV and DSV solenoids de-energized.
10. Restore set points for thermostat and humidistat.
© 2023 Carrier
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53500336-01
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Printed in U.S.A. Form 50FC-4-7-02SM
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Pg CL-2 7-23 Replaces: 50FC-4-7-01SM
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