TROUBLESHOOTING – AHC CONNECTION
| Symptom | Cause | 
| 
 | 
 | 
| 
 | Miswiring – Check wire colors to verify I- at AHC is connected to I- at | 
| 
 | thermostat and I+ is connected to I+. | 
| No RH display, no outdoor | AHC power source – When wired to the Model 8570 thermostat, the AHC | 
| temperature display | must be wired to a continuously ON power source. Use voltmeter to verify | 
| 
 | presence of 24VAC (nominal) at AHC. | 
| 
 | 
 | 
| 
 | AHC not operating correctly – check red diagnostic light on AHC. | 
| 
 | 
 | 
| No RH display, outdoor temperature OK | No valid reading available – run fan for at least 40 seconds. | 
| 
 | 
 | 
| RH display, outdoor temperature @ 20°F | AHC set for manual mode of operation. Wire an outdoor sensor to the AHC | 
| 
 | or wire an outdoor sensor to the thermostat. | 
| 
 | 
 | 
- 25 -