# Carrier Air V To Coleman Mach Iii Conversion Problems



## Justman (Jul 22, 2006)

All, need some help from fellow Outbackers on this one...

After experiencing some "issues" with my Carrier Air V (it left me stranded in 100+ heat), I replaced it with the Coleman Mach III Power Saver unit. Since I wanted to retain the use of the Carrier remote, I installed the Carrier to Coleman conversion kit that retains the use of the interior Carrier components, and thus the remote control.

Unfortunately, I found that the remote is about 10 degrees off after the transition. When set to 73, the AC turns off when the inside temp is at around 85 degrees---not good. I would just set a lower temp and call it good, but the remote only goes down to 63 (or so), which means the coolest we could get in the trailer would be 73. This is a bit on the hot side for me to sleep. I've tried resetting the remote a few times to no avail.

I'd like to install a digital thermostat to resolve the remote temp difference. I've scoured the net looking for instructions from people brighter than me who converted their Carrier unit to a wall thermostat, but I've not had any luck. I found some general instructions, but nothing that was simplified enough for me to follow...

Can someone assist? Seems like it would be simple enough to cut a few wires, match some wire colors, and then run and connect wires to a conveniently located thermostat.

Would greatly appreciate any assistance. Thanks!


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## Santa Fe TX Bob (Oct 30, 2011)

Justman,

It has been so long that I have sort of forgotten. I ran the thermostat 
wire down the duct that goes to the bathroom. I removed the paneling from 
the main room side of the bathroom wall to snake the wire down the wall. 
There is already a hole in the top plate that goes to the light switch on 
the inside of the bathroom. I unplugged the wires from the switch and 
pulled them back toward the light. Taped the thermostat wire to that an 
pulled it back
down. It was really slick.

I completely removed the thermostat card from the unit. Where it plugs in 
there are several wires. I cut them long at the connector and spliced into 
them there. Basically you have 4 relays. Fan high, fan low, compressor, 
and heat. By using a household thermostat I was able to run the fan with 
heat. It distributes the heat better by running the fan with the heat.

If you need some wiring guidance mail me before this evening and I will 
remove the covers and look.

Bob


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## CamperAndy (Aug 26, 2004)

The remote may be fine it is the location of the sensing probe. The little yellow thermistor must stick out below the inside cover. If it is pushed up inside it can read much cooler.


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## Santa Fe TX Bob (Oct 30, 2011)

I'd go hard wired regardless. You gain fan with no a/c or heat. Fan while furnace is on (mixes the air better for a more even heat). Programmable settings, i.e. you can set the thermostat to turn on the a/c an hour before you get back. The new thermostats are about $20.00 from home depot. An older household thermostat (mercury switch) won't work but the new ones have a digital temperature sensor and are battery operated. Even if I were to get a new unit, I would keep my wall thermostat.

Bob


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## ED_RN (Jun 25, 2006)

Not sure about new units but in my 2006 23RS the the remote had 3 settings fan, cool, and heat.


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## Justman (Jul 22, 2006)

All, thanks for the input. I apologize for not responding sooner. Things have been a bit busy at work lately and I've been working later than I like...

I took a look at the temp probe and I think it is getting erroneous readings from air being pulled over it. The new AC pushes quite a bit more air than my Carrier unit did, and it's pulling more air as well. I think it's sucking air through the hole the temp probe hangs down through and cooling to produce an artificially low temp.

I think I'll go with Bob's suggestion. I have an older thermostat that I had in another house that I think will work. It's a newer Hunter thermostat model 44860. Been collecting dust for 5 years, so I might as well put it to work, right? Now all I have to do is get the wiring correct.

Bob---if you get a chance and are willing, I'd appreciate a little help with the wiring. I'm pretty handy, so a simple list of the function of each wire would be great.

Thanks to all!


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## Santa Fe TX Bob (Oct 30, 2011)

The service manual has excellent wiring diagrams. www.transportaircon.carrier.com/Files/Bus/Local/US-en/T298.pdf The relays in the unit have 12v coils. Most thermostat wiring is standardized. It appears that the connections between the clicker-receiver and the powerbox assembly follow similar color codes. I also installed a snap action heat only thermostat over the refrigerator wired in parallel to the wall thermostat. That way when I am boon-docking I won't be using power to close the fan relay in the air-v. It is probably not significant but I am anal like that.


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## Ohana6164 (Oct 26, 2014)

Justman,

Where did you find the Coleman to Carrier conversion kit. I just had the Carrier replaced on my 21RS with a Coleman Mach 3. The Coleman's ceiling assembly hangs down too low and the pantry door doesn't fully open.
I would like to use the Carrier ceiling assembly and remote. The furnace is on it's own wall thermostat now. Had to get it up and running so I had the shop replace the a/c. (ouch$$). They couldn't find parts so the Coleman was the answer. Not real happy with craftsmanship or attention to detail.


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## TXJax (Dec 24, 2017)

I'm looking at the Coleman Mach 15 ducted to replace my Carrier V.

Does anyone done this? it has to operate my furnace, too.

How do you like it? Loud? Efficient? What?


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## Santa Fe TX Bob (Oct 30, 2011)

I got the Coleman Mach15® Heat Pump model from PPL with the AirV conversion kit. Heat pump works great down to about 35 degrees outside temperature. This model comes with a 2-speed fan but I have not hooked up the low speed which may be better when using the heat pump to have a hotter outlet temperature. On high speed fan the heat is a little drafty when it gets down below 40 outside.

https://www.pplmotorhomes.com/parts/rv-appliances/air-conditioner/air-conditioners-coleman-dometic/motor-home-air-conditioner_63150

*ob*


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