# Coleman Mach 5 Won't Run Correctly



## heron (May 13, 2010)

I upgraded from a 13.5 to a 15 AC last year. We used it once and it seemed fine. We went for a trial run last week and found that if we left the thermostat FAN ON and kept it on COOL it would not cool well. When I turned it to Auto it cooled fine. Any idea why this would happen. All ducts, etc...are sealed and in great order. It simply comes down to the unit not working right when the Fan is always on and the cool is selected...? Weird.


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## CamperAndy (Aug 26, 2004)

Should not make a difference. Are you sure you are not feeling warm air flow between actual cooling cycles? The AC will not run continually but will cycle as it is called for by the thermostat.


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## heron (May 13, 2010)

CamperAndy said:


> Should not make a difference. Are you sure you are not feeling warm air flow between actual cooling cycles? The AC will not run continually but will cycle as it is called for by the thermostat.


Yes, absolutely, it worked and cycled well last year..you could hear the compressor kick on but it didn't seem to happen. May be a thermostat issue. Not sure what type of replacement I can use with the Coleman. Not sure if the wiring is the same on one bought at Lowes or HD...?


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## 5windhams (Dec 14, 2010)

I found these instructions last year, and used them to upgrade to an automatic changeover thermostat from heat to a/c. You will lose the low/high fan speed switch unless you rig up one yourself, or just wire it for high speed only.


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## heron (May 13, 2010)

Thank you for those instructions. I may cross that bridge after our trip to St Andrews next week.


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## Insomniak (Jul 7, 2006)

There is also a digital Coleman thermostat that is a direct replacement for the cheapo analog model. Several of us have done that mod and it works well.


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## pep_ (Apr 27, 2012)

would this be the replacement one??
Digital Thermostat

for this analog one that we have in our TT currently?
Analog thermostat



Insomniak said:


> There is also a digital Coleman thermostat that is a direct replacement for the cheapo analog model. Several of us have done that mod and it works well.


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## LaydBack (Aug 22, 2010)

With the exception of the hi/low fan function, a stat from the local hardware will work just fine and at a fraction of the cost. I did a writeup on here when I installed mine, and the link in my sig should have pics that explain it as well. The hi/low switch can go at the stat or on the unit, whichever you prefer or is easier. If you have any more questions, I'd be more than happy to help you save a few bucks.


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## Insomniak (Jul 7, 2006)

pep_ said:


> There is also a digital Coleman thermostat that is a direct replacement for the cheapo analog model. Several of us have done that mod and it works well.


[/quote]
No, that one is for heat pump applications. Try this one:

http://www.rvplus.com/coleman-digital-h-c-thermostat-u-8330-3362.html?utm_source=spring&utm_medium=ise&utm_content=66.00&utm_campaign=spring


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## pep_ (Apr 27, 2012)

Thanks for the link insomniak. Laydback, I will most likely stick with the regular Coleman digital thermostat. I might be in touch on a couple of your other mods though. Some good ones there.


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## Good Times (Jan 23, 2012)

Here is a link for the digital thermostat I installed in my 301BQ. http://www.rvplus.com/coleman-digital-h-c-thermostat-u-8330-3362.html Have been fairly happy with performance...although wishing we had the 15,000btu instead of the 13,500btu a/c unit.


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