Carrier 50PM20 Installation Instructions Manual page 45

No Heat.
PROBLEM
Table 12 - Heating Service Analysis
CAUSE
Power failure.
Fuse blown or circuit breaker tripped.
CB1, CB2, CB3.
Thermostat not calling for heating.
No 24 vac at primary contactor.
No power (high voltage) to L2 of
primary contactor.
Bad electrical elements.
REMEDY
Call power company.
Replace fuse or reset circuit breaker.
Check thermostat.
Check transformer and circuit breaker.
Check safety switches, one shot backup,
and auto limit.
With power off, remove high voltage wires and
check resistance of heater. Replace if open.
EconoMi$er IV Troubleshooting
EconoMi$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.
IMPORTANT: Be sure to record the positions of all
potentiometers before starting troubleshooting.
1. Disconnect power at TR and TRI. All LEDs should be off.
Exhaust fan contacts should be open.
2. Disconnect device at P and PI.
3. Jumper P to PI.
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
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 TRI.
Differential Enthalpy
To check differential enthalpy:
1. Make sure EconoMi$er IV preparation procedure has been
performed.
2. Place 620-ohm resistor across So and +.
3. Place 1.2 kilo-ohm resistor across SR and +. The Free Cool
LED should be lit.
4. Remove 620-ohm resistor across So and +. The Free Cool
5.
and wiring to normal
LED should turn off.
Return EconoMi$er IV settings
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$er IV preparation procedure has been
performed.
2. Ensure terminals AQ and AQI are open. The LED for both
DCV and Exhaust should be off. The actuator should be
fully closed.
3. Connect a 9-v battery to AQ (positive node) and AQ1
(negative node). The LED for both DCV and Exhaust
should turn on. The actuator should drive to between 90
and 95% open.
4. Turn the Exhaust potentiometer CW until the Exhaust LED
turns off. The LED should turn off when the
potentiometer is approximately 90%. The actuator should
remain in position.
5. Turn the DCV set point potentiometer CW until the DCV
LED turns off. The DCV LED should turn off when the
potentiometer is approximately 9 v. The actuator should
drive fully closed.
6. Turn the DCV and Exhaust potentiometers CCW until the
Exhaust LED turns on. The exhaust contacts will close 30
to 120 seconds after the Exhaust LED turns on.
7. Return EconoMi$er IV 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$er IV preparation procedure has been
performed.
2. Connect a 9-v battery to AQ (positive node) and AQ1
(negative node). The DCV LED should turn on. The
actuator should drive to between 90 and 95% open.
3. Turn the DCV Maximum Position potentiometer to
midpoint. The actuator should drive to between 20 and 80%
open.
4. Turn the DCV Maximum Position potentiometer to fully
CCW. The actuator should drive fully closed.
5. Turn the Minimum Position potentiometer to midpoint. The
actuator should drive to between 20 and 80% open.
6. Turn the Minimum Position Potentiometer fully CW. The
actuator should drive fully open.
7. Remove the jumper from TR and N. The actuator should
drive fully closed.
8. Return EconoMi$er IV settings and wiring to normal
after completing troubleshooting.
Mixed Air
Input
To check mixed air 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.
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