Carrier 50FC 04 Series Service And Maintenance Instructions page 40

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 EconoMi$er
been performed.
2. Place 620-ohm resistor across SO and +.
3. Place 1.2 kilo-ohm resistor across SR and +. The Free
Cool LED should be lit.
4. Remove 620-ohm resistor across SO and +. The Free Cool
LED should turn off.
5. Return EconoMi$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$er IV preparation procedure has been
performed.
2. Ensure terminals AQ and AQ1 are open. The LED for
both DCV and Exhaust should be off. The actuator should
be fully closed.
3. Connect a 9-v battery to AQ (positive node) and AQ1
(negative node). The LED for both DCV and Exhaust
should turn on. The actuator should drive to between 90
and 95% open.
4. Turn the Exhaust potentiometer CW until the Exhaust
LED turns off. The LED should turn off when the potenti-
ometer is approximately 90%. The actuator should remain
in position.
5. Turn the DCV set point potentiometer CW until the DCV
LED turns off. The DCV LED should turn off when the
potentiometer is approximately 9-v. The actuator should
drive fully closed.
6. Turn the DCV and Exhaust potentiometers CCW until the
Exhaust LED turns on. The exhaust contacts will close 30
to 120 seconds after the Exhaust LED turns on.
7. Return EconoMi$er IV settings and wiring to normal after
completing troubleshooting.
IV preparation procedure has
®
DCV MINIMUM AND MAXIMUM POSITION
To check the DCV minimum and maximum position:
1. Make sure EconoMi$er IV preparation procedure has been
performed.
2. Connect a 9-v battery to AQ (positive node) and AQ1
(negative node). The DCV LED should turn on. The actua-
tor should drive to between 90 and 95% open.
3. Turn the DCV Maximum Position potentiometer to mid-
point. The actuator should drive to between 20 and 80%
open.
4. Turn the DCV Maximum Position potentiometer to fully
CCW. The actuator should drive fully closed.
5. Turn the Minimum Position potentiometer to mid-point.
The actuator should drive to between 20 and 80% open.
6. Turn the Minimum Position Potentiometer fully CW. The
actuator should drive fully open.
7. Remove the jumper from TR and N. The actuator should
drive fully closed.
8. Return EconoMi$er IV settings and wiring to normal after
completing troubleshooting.
SUPPLY-AIR SENSOR INPUT
To check supply-air sensor input:
1. Make sure EconoMi$er IV preparation procedure has been
performed.
2. Set the Enthalpy potentiometer to A. The Free Cool LED
turns on. The actuator should drive to between 20 and 80%
open.
3. Remove the 5.6 kilo-ohm resistor and jumper T to T1. The
actuator should drive fully open.
4. Remove the jumper across T and T1. The actuator should
drive fully closed.
5. Return EconoMi$er IV settings and wiring to normal after
completing troubleshooting.
ECONOMI$ER IV TROUBLESHOOTING COMPLETION
This procedure is used to return the EconoMi$er IV 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.
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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