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5. Press Mode to move through the variables.
6. Press Enter to lock in the selection, then press Mode
to continue to the next variable.
Dehumidification of Fresh Air with DCV (Demand
Controlled Ventilation) Control
If norma l rooftop heating and cooling operation is not
adequa te for the outdoor humidity level, an energy
recove ry unit and/or a dehumidification opt ion should be
considered.
EconoMi$e r IV Pr
eparation
This procedure is used to prepare the EconoMi$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 whic h are
not supplied with the EconoMi$er IV.
IMPORTANT: Be sure to record the positions of all
potentiometers before starting troubleshooting.
1. Disconnect powe r at TR and TR1. All LEDs should
be off. Exhaust fan contacts should be open.
2. Disconnect device at P and P1.
3. Jumper P to P1.
4. Disconnect wires at T and T1. Place 5.6 kilo--ohm
resistor across T and T1.
5. Jumper TR to 1.
6. Jumper TR to N.
7. If connected, remove sensor from terminals SO and +.
Connect 1.2 kilo--ohm 4074EJM checkout resistor
across terminals SO and +.
8. Put 620--ohm resistor across termi nals SR and +.
9. Set minimum position, DCV setpoint, and exhaust po-
tentiometers fully CCW (counterclockwise).
10. Set DCV maximum position potentiometer fully CW
(clockwise).
11. Set enthalpy potentiometer to D.
12. Apply power (24 vac) to terminals TR and TR1.
Differential
Enthalpy
To check differential enthalpy:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Place 620--ohm resistor across 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$er IV settings and wiring to normal
afte r completing troubleshooting.
Single
Enthalpy
To check single enthalpy:
1. Make sure EconoMi$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$er IV settings and wiring to normal
afte r completing troubleshooting.
DCV (Demand Controlled Ventilation) and
Power
Exhaust
To check DCV and Power Exhaust:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Ensure termi nals AQ and AQ1 are open. T he 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
(negat ive 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 potentiom eter CW until the Exhaust
LED turns off. The LED should turn off when the po-
tentiometer is approximately 90%. The actuator
should remain in position.
5. Turn the DCV setpoint potentiometer CW until the
DCV LED turns off. The DCV LED should turn off
when the potentiometer is approximately 9--v. The ac-
tuator 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$er IV settings and wiring to normal
afte r completing troubleshooting.
DCV Minimum a nd Maximum
Position
To check the DCV minimum and maximum position:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Connect a 9--v battery to AQ (positive node) and AQ1
(negat ive node). The DCV LED should turn on. The
act uator 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 mid-
point. The act uator 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$er IV settings and wiring to normal
afte r completing troubleshooting.
Supply--Air Sensor
Input
To check supply--air sensor input:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
50TC