| Table 12 – CADM Troubleshooting |
|
|
Miswired Module Indication | Recommended Troubleshooting Action |
Green LED is not on, | Determine if both R and C module terminals are connected. Verify voltage in present at module’s R |
module does not power up | and C terminals. |
| NOTE: The CADM requires a constant nominal 24VAC power supply. The wiring to the module’s R |
| and C terminals must be directly from the control transformer. The module cannot receive its power |
| from another device that will interrupt the 24VAC power supply. See the 38AU Wiring Diagram(s) |
| (Fig. 29 and Fig. 30). |
|
|
Green LED Intermittent, | Determine if R and Y terminals are wired in reverse. Verify module’s R and C terminals have a con- |
module powers up only | stant source. See “NOTE” above for details on R and C wiring. |
when compressor runs |
|
|
|
TRIP LED is on but system | Verify Y terminal is wired properly per the 38AU wiring diagram (see Fig. 29 and Fig. 30). Verify |
and compressor check OK | voltage at contactor coil falls below 0.5VAC when off. Verify 24VAQC is present across Y and C |
| when thermostat demand signal is present. If not, R and C are reverse wired. |
|
|
TRIP LED and ALERT LED | Verify R and C terminals are supplied with |
flashing together |
|
|
|
ALERT Flash Code 3 | Verify Y terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below |
(Compressor Short Cycling) | 0.5VAC when off. |
displayed incorrectly |
|
|
|
ALERT Flash Code 5 or 6 | Check that compressor T1 and T3 wires are through module’s current sensing holes. Verify Y ter- |
(Open Circuit, Missing Phase) | minal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below 0.5VAC |
displayed incorrectly | when off. |
|
|
Alert Flash Code * | Determine if module’s Y terminal is connected. Verify Y terminal is connected to 24VAC at contactor |
(Welded Contactor) | coil. Verify 24VAC is present across Y and C when thermostat demand signal is present. If not, R |
displayed incorrectly | and C are reverse wired. Verify voltage at contactor coil falls below 0.5VAC when off. |
|
|
38AU
Compressor Protection
Compressor Overtemperature Protection (IP) —
A thermostat installed on the compressor motor winding reacts to excessively high winding temperatures and shuts off the compressor.
Crankcase Heater —
The heater minimizes absorption of liquid refrigerant by oil in the crankcase during brief or extended shutdown periods. The heater is wired to cycle with the compressor; the heater is off when compressor is running, and on when compressor is off.
The crankcase heater will operate as long as the power circuit is energized. The main disconnect must be on to energize the crankcase heater.
IMPORTANT: Never open any switch or disconnect that energizes the crankcase heater unless unit is being serviced or is to be shut down for a prolonged period. After a prolonged shutdown on a service job, energize the crankcase heater for 24 hours before starting the compressor.
Advanced Scroll Temperature Protection (ASTP) —
See “Advanced Scroll Temperature Protection (ASTP)” on page 24.
Low-Pressure Switch —
The 38AU
High-Pressure Switch —
The
Outdoor Fans —
Each fan is supported by a
1.Shut off unit power supply. Install lockout tag.
2.Remove outdoor fan assembly (grille, motor, and fan).
3.Loosen fan hub setscrews.
4.Adjust fan height as shown in Fig. 33.
5.Tighten setscrews to 84
6.Replace outdoor fan assembly.
3.6 mm
C10103
Fig. 33 - Outdoor Fan Blade Position
Lubrication —
Fan Motors: The fan motors have sealed bearings. No provisions are made for lubrication.
Compressor: The compressor has its own oil supply. Loss of oil due to a leak in the system should be the only reason for adding oil after the system has been in operation.
37
