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49
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.
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$er IV preparation procedure has
been performed.
2. Place 620-ohm resistor across S
O
and +.
3. Place 1.2 kilo-ohm resistor across S
R
and +. The Free
Cool LED should be lit.
4. Remove 620-ohm resistor across S
O
and +. The Free
Cool LED should turn off.
5. Return EconoMi$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.
IMPORTANT: Be sure to record the positions of all poten-
tiometers before starting troubleshooting.
Fig. 49 — Cooling Charging Chart, 50TFQ012
Fig. 48 — Cooling Charging Chart, 50TFQ009