Carrier 48HJ015-025 Economizer Checkout Procedures, High and Low Outdoor-Air Temperature

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 ®lters 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 Ð 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 SO and +. Factory-installed

800 ohm resistor should re- main connected to SR 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 SR
and +.	1.	LED (light-emitting diode)
		should be on.
	2.	Motor drives toward open.

Table 9 Ð High and Low Outdoor-Air Temperature

TEST PROCEDURE RESULTS

A.Reconnect factory-installed 800 ohm resistor between ter- minals SR and +.

B.Connect 1200 ohm checkout

resistor between terminals SO 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 Ð 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 Ð 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 Ð Use standard evacuating techniques. After evacuating system, weigh in the speci®ed amount of refrigerant (refer to Table 1).

LOW CHARGE COOLING Ð 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 Ð 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 Ð If pilots do not light as described in Gas Heat section on page 17, be sure that pilot ori®ce 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 Ð Cooling Charging Chart, 48HJ015

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