Start-up, Constant volume units – Carrier 50DF034 User Manual

Page 10

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CIRCUIT BREAKERS

CONVENIENCE OUTLET LOW AMBIENT LOCKOUT

THERMOSTAT

LOOIC PANEL

Fig. 13 — Control Box

MOVE SWITCH TO
POSITION FOR

DESIRED HEATING SETBACK

(A) HEATING SETBACK

Fig. 14

(B)COOLING SETUP OR LOCKOUT

Accessory Setback/Setup Module (Partial)

START-UP

Constant Volume Units

COOLING (WITH OR WITHOUT ENERGY

MANAGEMENT ACCESSORY)

1. Open compressor service valves. Make sure the crank

case heater has been on for at least 24 hours to remove

liquid refrigerant from compressor crankcase. Check

compressor oil level. Oil sight glass should be half full.

2. Be sure that the liquid line service valve is open and

that high- and low-side refrigerant service ports are
closed as applicable.

3. On units equipped with the energy management acces

sory, move the COOL SETUP SELECT jumper wire
to the desired setting (5°, 8°, or 12°). If cooling is not
desired during the unoccupied periods, move jumper
wire from COOL SETUP to COOL LOCKOUT. See

Fig 14.

4. Turn on power to unit. On standard units, set the

subbase selector switch to COOL. On units with the

energy management accessory, set the 7-day time clock

as required. Refer to 7-Day Time Clock Adjustment.

Check that compressor low ambient lockout contacts

and morning warm-up contacts (on units with energy

management accessory) are closed.

5. Remove cover from thermostat (or from transmitter

if a remote sensor is used); note the red diagnostic

light-emitting diodes (LED’s). See Fig. 15.

6. To call for cooling, move the thermostat or transmitter

cooling set point (blue lever) below room temperature.

Cooling LED on the right-hand side of thermostat or

transmitter should begin to glow. Check the cooling

effect at supply duct outlets If the mechanical cooling
does not come on, see Service, Electronic Component
Checkout.

7. Move the thermostat or transmitter cooling set point

above room temperature. The cooling equipment

should cycle off and the cooling LED intensity should
decrease to a faint glow or go off completely. The
economizer should move to minimum position.