American Aldes DHV-150H Manuel D’Utilisation

 

10

maintain nearly constant pressure and temperature 
across the entire coil, from inlet to outlet. 
 
The mixture of gas and liquid refrigerant enter the 
accumulator after leaving the evaporator coil. The 
accumulator prevents any liquid refrigerant from 
reaching the compressor. The compressor evacuates 
the cool refrigerant gas from the accumulator and 
compresses it to a high pressure and temperature to 
repeat the process. 
 

 

 
No dehumidification, neither fan nor compressor 
run with fan switch and ventilation timer OFF. 

1.  Unit unplugged or no power to outlet. 
2.  Humidity control set too high or defective 

(Sec. 3.3 & 5.7A) 

3.  Loose connection in internal or control wiring. 
4.  Defective Compressor relay. 
5.  Defective control transformer. 
6.  Low pressure Control open (Sec 3.7 & 5.10). 
7.  Optional Condensate Pump Safety Switch open 

(Sec 5.11). 

 

1.  Defective compressor run capacitor (Sec. 5.6). 
2.  Bad connection in compressor circuit (See 

Fig. 4). 

3.  Defective compressor overload (Sec. 5.6A). 
4.  Defective compressor (Sec. 5.6). 
5.  Defrost thermostat open (Sec. 5.8). 

 

1.  Low ambient temperature and/or humidity 

causing unit to cycle through defrost mode. 

2.  Defective compressor overload (Sec. 5.6A). 
3.  Defective compressor (Sec. 5.6). 
4.  Defrost thermostat defective (Sec. 5.8). 
5.  Dirty air filter(s) or airflow restricted. 
6.  Low refrigerant charge, causing defrost control 

to cycle. 

7.  Bad connection in compressor circuit. 

 
Fan does not run with fan switch in either 
position. Fan does not run with ventilation timer 
activated. Compressor runs briefly but cycles on & 
off with humidity control turned to ON. 

1.  Loose connection in fan circuit (See Fig. 4). 
2.  Obstruction prevents fan impeller rotation. 
3.  Defective fan. 
4.  Defective fan relay. 
5.  Defective fan capacitor. 

1.  Ventilation timer set to manual & switched OFF. 
2.  Time not correct on ventilation timer. 
3.  Defective ventilation timer. 
4.  Defective fan switch. 

 
Evaporator coil frosted continuously, low 
dehumidifying capacity. 

1.  Dirty air filter(s) or airflow restricted. 
2.  Excessively restrictive ducting connected to unit. 
3.  Defrost thermostat loose or defective (Sec. 5.8). 
4.  Low refrigerant charge 

 

1.  If timer is not functioning correctly reset timer 

and reprogram (Sec. 3.5). 

2.  Check control wire connections (check 

connections at fresh air damper also). 

3.  Defective fresh air damper (Sec. 5.9). 
4.  Defective fan switch. 

 

expected. 
1.  Air temperature and/or humidity have dropped. 
2.  Humidity meter and or thermometer used are 

out of calibration. 

3.  Unit has entered defrost cycle (Sec. 5.8). 
4.  Air filter dirty (Sec. 4.1 & 4.2). 
5.  Defective defrost thermostat (Sec 5.8). 
6.  Low refrigerant charge (Sec. 5.4). 
7.  Air leak such as loose cover or ducting leaks. 
8.  Defective compressor (Sec. 5.6). 
9.  Restrictive ducting (Sec. 2.4). 
10.  Optional Condensate Pump Safety Switch open 

(Sec 5.11). 

 

1.  Detach field control wiring connections from 

main unit. 

2.  Connect the yellow and green pigtails from the 

main unit together; only the fan should run. 
Disconnect the wires. 

3.  Connect the yellow and blue pigtails from the 

main unit together; the compressor and fan 
should run. 

4.  If these tests work, the main unit is working 

properly. You should check the control panel and 
field control wiring for problems next. 

5.  Remove the control panel from the mounting box 

and detach it from the field installed control 
wiring. Connect the blue, yellow, and green wires 
from the control panel directly to the 
corresponding colored pigtails on the main unit. 
Leave the violet, white and red wires 
disconnected!