Aprilaire Model 8570 User Manual

Page 29

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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.

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TROUBLESHOOTING – AHC CONNECTION

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