Bryant 604D--A Troubleshooting, 604D-- --A, Disconnect device at P and P1 3.Jumper P to P1

604D-- -- A

TROUBLESHOOTING

See Table 17 for Economizer logic. An Economizer simulator program is available to help with Economizer training and troubleshooting.

Economizer Preparation —This procedure is used to prepare the Economizer 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 Economizer.

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 poten- tiometers fully CCW (counterclockwise).

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

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 Economizer 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 Economizer settings and wiring to normal after completing troubleshooting.

Single Enthalpy—To check single enthalpy:

1.Make sure Economizer 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 Economizer settings and wiring to normal after completing troubleshooting.

DCV (Demand Controlled Ventilation) and Power Exhaust—To check DCV and Power Exhaust:

1.Make sure Economizer 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.

5.Turn the DCV set point potentiometer CW until the DCV LED turns off. The DCV LED should turn off when the potentiometer is approximately 9-v. The actuator should drive fully closed.

6.Turn the DCV and Exhaust potentiometers CCW until the Exhaust LED turns on. The exhaust contacts will close 30 to 120 seconds after the Exhaust LED turns on.

7.Return Economizer settings and wiring to normal after completing troubleshooting.

DCV Minimum and Maximum Position —To check the DCV minimum and maximum position:

1.Make sure Economizer preparation procedure has been performed.

2.Connect a 9-v battery to AQ (positive node) and AQ1 (negative node). The DCV LED should turn on. The actu- ator should drive to between 90 and 95% open.

3.Turn the DCV Maximum Position potentiometer to midpoint. The actuator should drive to between 20 and 80% open.

4.Turn the DCV Maximum Position potentiometer to fully CCW. The actuator should drive fully closed.

5.Turn the Minimum Position potentiometer to midpoint. The actuator should drive to between 20 and 80% open.

6.Turn the Minimum Position Potentiometer fully CW. The actuator should drive fully open.

7.Remove the jumper from TR and N. The actuator should drive fully closed.

8.Return Economizer settings and wiring to normal after completing troubleshooting.

Supply-AirInput—To check supply-air input:

1.Make sure Economizer preparation procedure has beenperformed.

2.Set the Enthalpy potentiometer to A. The Free Cool LED turns on. The actuator should drive to between 20 and 80% open.

3.Remove the 5.6 kilo-ohm resistor and jumper T to T1. The actuator should drive fully open.

4.Remove the jumper across T and T1. The actuator should drive fully closed.

5.Return Economizer settings and wiring to normal after completing troubleshooting.

Economizer Troubleshooting Completion —This procedure is used to return the Economizer to operation. No troubleshooting or testing is done by performing the following procedure.

1.Disconnect power at TR and TR1.

2.Set enthalpy potentiometer to previous setting.

3.Set DCV maximum position potentiometer to previous setting. Set DVC Max potentiometer to fully closed (CCW) when not using a CO2 sensor.

4.Set minimum position, DCV set point, and exhaust poten- tiometers to previous settings.

5.Remove 620-ohm resistor from terminals SR and +.

6.Remove 1.2 kilo-ohm checkout resistor from terminals SO and +. If used, reconnect sensor from terminals SO and +.

7.Remove jumper from TR to N.

8.Remove jumper from TR to 1.

9.Remove 5.6 kilo-ohm resistor from T and T1. Reconnect wires at T and T1.

10.Remove jumper from P to P1. Reconnect device at P and P1.

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

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