Carrier 50TFQ008-012 specifications Troubleshooting, Cooling Charging Chart, 50TFQ009

Fig. 48 — Cooling Charging Chart, 50TFQ009

TROUBLESHOOTING

Unit Troubleshooting — For unit troubleshooting, re- fer to Fig. 50 and Table 28.

EconoMi$er IV Troubleshooting — See Table 29 for EconoMi$er IV logic.

A functional view of the EconoMi$er IV is shown in Fig. 51. Typical settings, sensor ranges, and jumper positions are also shown. An EconoMi$er IV simulator program is avail- able from Carrier to help with EconoMi$er IV training and troubleshooting.

ECONOMI$ER IV PREPARATION — This procedure is used to prepare the EconoMi$er IV for troubleshooting. No troubleshooting or testing is done by performing the following procedure.

NOTE: This procedure requires a 9-v battery, 1.2 kilo-ohm resistor, and a 5.6 kilo-ohm resistor which are not supplied with the EconoMi$er IV.

IMPORTANT: Be sure to record the positions of all poten- tiometers before starting troubleshooting.

1.Disconnect power at TR and TR1. All LEDs should be off. Exhaust fan contacts should be open.

2.Disconnect device at P and P1.

3.Jumper P to P1.

4.Disconnect wires at T and T1. Place 5.6 kilo-ohm resistor across T and T1.

5.Jumper TR to 1.

6.Jumper TR to N.

7.If connected, remove sensor from terminals SO and +. Connect 1.2 kilo-ohm 4074EJM checkout resistor across terminals SO and +.

8.Put 620-ohm resistor across terminals SR and +.

9.Set minimum position, DCV set point, and exhaust potentiometers fully CCW (counterclockwise).

10.Set DCV maximum position potentiometer fully CW (clockwise).

Fig. 49 — Cooling Charging Chart, 50TFQ012

11.Set enthalpy potentiometer to D.

12.Apply power (24 vac) to terminals TR and TR1.

DIFFERENTIAL ENTHALPY — To check differential enthalpy:

1.Make sure EconoMi$er IV preparation procedure has been performed.

2.Place 620-ohm resistor across SO and +.

3.Place 1.2 kilo-ohm resistor across SR and +. The Free Cool LED should be lit.

4.Remove 620-ohm resistor across SO and +. The Free Cool LED should turn off.

5.Return EconoMi$er IV settings and wiring to normal after completing troubleshooting.

SINGLE ENTHALPY — To check single enthalpy:

1.Make sure EconoMi$er IV preparation procedure has been performed.

2.Set the enthalpy potentiometer to A (fully CCW). The Free Cool LED should be lit.

3.Set the enthalpy potentiometer to D (fully CW). The Free Cool LED should turn off.

4.Return EconoMi$er IV settings and wiring to normal after completing troubleshooting.

DCV (DEMAND CONTROLLED VENTILATION) AND POWER EXHAUST — To check DCV and Power Exhaust:

1.Make sure EconoMi$er IV preparation procedure has been performed.

2.Ensure terminals AQ and AQ1 are open. The LED for both DCV and Exhaust should be off. The actuator should be fully closed.

3.Connect a 9-v battery to AQ (positive node) and AQ1 (negative node). The LED for both DCV and Exhaust should turn on. The actuator should drive to between 90 and 95% open.

4.Turn the Exhaust potentiometer CW until the Exhaust LED turns off. The LED should turn off when the potentiometer is approximately 90%. The actuator should remain in position.

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