Carrier 48TM016-028 - Manual (Page 51)

51
TROUBLESHOOTING
Unit Troubleshooting — Refer to Tables 27-29 and
Fig. 59.
EconoMi$erIV Troubleshooting — See Table 30
for EconoMi$er IV logic.
A functional view of the EconoMi$erIV is shown in
Fig. 60. Typical settings, sensor ranges, and jumper positions
are also shown. An EconoMi$erIV simulator program is
available from Carrier to help with EconoMi$erIV training and
troubleshooting.
ECONOMI$ERIV PREPARATION — This procedure is
used to prepare the EconoMi$erIV for troubleshooting. No
troubleshooting or testing is done by performing the following
procedure.
NOTE: This procedure requires a 9-v battery, 1.2 kilo-ohm
resistor, and a 5.6 kilo-ohm resistor which are not supplied
with the EconoMi$erIV.
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 S
O
and +.
Connect 1.2 kilo-ohm 4074EJM checkout resistor across
terminals S
O
and +.
8. Put 620-ohm resistor across terminals S
R
and +.
9. Set minimum position, DCV set point, and exhaust
potentiometers 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$erIV preparation procedure has
been performed.
2. Place 620-ohm resistor across S
O
and +.
3. Place 1.2 kilo-ohm resistor across S
R
and +. The Free
Cool LED should be lit.
4. Remove 620-ohm resistor across S
O
and +. The Free
Cool LED should turn off.
5. Return EconoMi$erIV settings and wiring to normal
after completing troubleshooting.
SINGLE ENTHALPY — To check single enthalpy:
1. Make sure EconoMi$erIV preparation procedure has
been performed.
2. Set the enthalpy potentiometer to A (fully CCW). The
Free Cool LED should be lit.
3. Set the enthalpy potentiometer to D (fully CW). The Free
Cool LED should turn off.
4. Return EconoMi$erIV 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$erIV preparation procedure has
been performed.
2. Ensure terminals AQ and AQ1 are open. The LED for
both DCV and Exhaust should be off. The actuator
should be fully closed.
3. Connect a 9-v battery to AQ (positive node) and AQ1
(negative node). The LED for both DCV and Exhaust
should turn on. The actuator should drive to between 90
and 95% open.
4. Turn the Exhaust potentiometer CW until the Exhaust
LED turns off. The LED should turn off when the
potentiometer is approximately 90%. The actuator should
remain in position.
5. Turn the DCV set point potentiometer CW until the DCV
LED turns off. The DCV LED should turn off when the
potentiometer is approximately 9 v. The actuator should
drive fully closed.
6. Turn the DCV and Exhaust potentiometers CCW until
the Exhaust LED turns on. The exhaust contacts will
close 30 to 120 seconds after the Exhaust LED turns on.
7. Return EconoMi$erIV settings and wiring to normal
after completing troubleshooting.
DCV MINIMUM AND MAXIMUM POSITION — To check
the DCV minimum and maximum position:
1. Make sure EconoMi$erIV preparation procedure has
been performed.
2. Connect a 9-v battery to AQ (positive node) and AQ1
(negative node). The DCV LED should turn on. The
actuator should drive to between 90 and 95% open.
3. Turn the DCV Maximum Position potentiometer to mid-
point. The actuator should drive to between 20 and 80%
open.
4. Turn the DCV Maximum Position potentiometer to fully
CCW. The actuator should drive fully closed.
5. Turn the Minimum Position potentiometer to midpoint.
The actuator should drive to between 20 and 80% open.
6. Turn the Minimum Position Potentiometer fully CW. The
actuator should drive fully open.
7. Remove the jumper from TR and N. The actuator should
drive fully closed.
8. Return EconoMi$erIV settings and wiring to normal
after completing troubleshooting.
SUPPLY-AIR INPUT — To check supply-air input:
1. Make sure EconoMi$erIV preparation procedure has
been performed.
2. Set the Enthalpy potentiometer to A. The Free Cool LED
turns on. The actuator should drive to between 20 and
80% open.
3. Remove the 5.6 kilo-ohm resistor and jumper T to T1.
The actuator should drive fully open.
4. Remove the jumper across T and T1. The actuator should
drive fully closed.
5. Return EconoMi$erIV settings and wiring to normal
after completing troubleshooting.
ECONOMI$ERIV TROUBLESHOOTING COMPLE-
TION — This procedure is used to return the EconoMi$erIV
to operation. No troubleshooting or testing is done by perform-
ing 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
potentiometers to previous settings.
5. Remove 620-ohm resistor from terminals S
R
and +.
6. Remove 1.2 kilo-ohm checkout resistor from terminals
S
O
and +. If used, reconnect sensor from terminals S
O
and
+.
IMPORTANT: Be sure to record the positions of all poten-
tiometers before starting troubleshooting.