Miller 200 Fan Questions

RonG · Jul 13, 2021

Picked up a Miller 200 Mig to replace my Lincoln 180. It is a 1987 model. Seems to work well but the cooling fan isn't turning on with the main power switch. Should it be on full time or does it kick on as needed? I am in the process of cleaning up the machine and havent really welded with it yet.

M J D · Jul 13, 2021

Fan on demand

RonG · Jul 13, 2021

Thank you very much..now to learn to weld

ToolFanGeoff · Jul 14, 2021

Ron, I have a MM200 that is older than yours - so check that this is the same for yours. My MM200 fan runs all the time the machine switch is turned on. Check out this thread on the Miller site:
1979 MM200 Millermatic 200 Fan Motor Repair - Miller Welding Discussion Forums (millerwelds.com)

I hope it helps.
Geoff

G-ManBart · Jul 14, 2021

I have had a number of MM200s and some had full-time fans while others had fan-on-demand. The manual for a machine made in 1987 shows fan-on-demand so if he got the year right, he should be fine.

guajilloweld03 · Jul 14, 2021

Check the capacitors and verify they are not bad. When they go bad they will cause the rectifier to heat up and trip TP2 or TP3. While your at it check the diodes.

From research TP2 is 105 degrees to open and 125 degrees to close.

TP3 is 150 degrees to close and 180 degrees to open.

Miller 200 Fan Questions

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