# Exhaust fan issue for Jennair cooktop CVG2420W



## anku (Jun 18, 2009)

Hi,
Recently I had exhaust fan issue for Jennair downdraft cooktop model CVG2420W. All of a sudden it started making big humming sound when no flame was going and fan was off i.e. cooktop was not in use.

Upon close inspection I found that there was voltage ~70VAC to the exhaust fan terminal (you can measure it with a multimeter by disconnecting the fan cable from it's socket) when fan control switch was on off. First I wasn't sure if fan motor had gone bad. I disconnected the fan and took it to garage. There when I connected the fan cable to 110VAC, exhaust fan was running smoothly. I also bypassed fan control switch terminal on the cooktop and found exhaust fan was running fine. These 2 test confirmed that I had bad fan control switch.

Original fan control switch info :
Part# PHS120A-3377
Solid State Control
Cust# 208684
Time delay 40A INRUSH
120VAC, 3.7A

Now the fun part, above part is not longer available. It has been replaced by Whirlpool part #74009254. Searching on the web I found that some other folk had trouble with the orientation of the fan control knob. Notch on this new replacement part was swapped. I.e. Fan control knob marking would not be at 'off marking' when fan was off.
To fix this issue, I straightened the protruding metal on the metal frame plate (to which fan control switch is tightened/anchored). Once I made space, I was able to rotate fan control switch and fastened the holding nut to the metal plate. I reconnected all cables and now cooktop is working as expected.

FYI ... Exhaust fan hot wire comes from wall socket and then it goes to the fan control switch. Output of fan control switch goes to hot wire of exhaust fan i.e. fan control switch is in series to the fan circuit.

Hope this info help someone down the road. Happy diy !! :thumbup:


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