Roof refer Duo Therm

[Jack Gruer]

bought a used Duo Therm roof refer and when plugged in it cool and fans but will not turn off. The fan runs continuous in both cool and fan positions. I cannot see any change in fan speed in low, med or high and in off it isn't. I have two of the same units and they both act the same Any ideas before the real heat sets in out here in Cornville, AZ? Cheers, Jack

[Lakota Wolf]

A standard DuoTherm roof a/c has a continuous fan cycle, meaning the fan runs all the time and the a/c compressor kicks in at selected temp and when the temp is achieved, the a/c compressor kicks off BUT the fan continues to run, On upgraded models they have a duty cycle fan, Which the fan engages first,, then a/c compressor,, when temp is achieved,, a/c compressor kicks off, and the fan runs a short cycle before completely shutting down.

As far as NOT having a Low ,Med, or High, control... or its just staying on one speed,, could be a faulty fan selector switch. I hope this minimal info helps... good luck.