Replacement AC System for a Coleman Mach Polar Cub w/a Heat Pump  

Question:

Expert Reply:

Welcome back Tim! To replace and upgrade your Coleman Mach Polar Cub with heat pump that is ducted, I recommend the Mach 8 Plus RV AC w/ Heat Pump item # CM95MR, along with the Coleman-Mach CHILLGrille Ducted Ceiling Assembly for Heat Pumps item # CM48GR, and the Single Zone Digital Thermostat item # CM76RR.

There's no way to just replace your Mach Polar Cub AC unit, you'll need to replace all your AC system components. This is due to the EPA changing the regulations on the refrigerant in the AC units at the beginning of 2025. They've been upgraded to R32 and your Coleman Mach has the now obsolete 410a refrigerant. None of the 410a components are compatible now with the newer systems including your 8xxx series thermostat and controls. You will be able to use the existing wiring to power the AC system and connect the new thermostat, which means there will be minimal rewiring.

The Mach 8 Plus RV AC w/ Heat Pump item # CM95MR is a 15,000 Btu AC with a heat pump. This will be a solid upgrade from your 9,200 Btu system. It will plug directly into the Coleman-Mach CHILLGrille Ducted Ceiling Assembly item # CM48GR. The only wiring you'll need to do is connecting the 115v power supply and the thermostat wiring.

What kind of climates do you usually camp in with your motorhome?

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expert reply by: Jerred H

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CM76RR
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Tim W.

8/2/2026

Jerred; I see two potential issues with this: 1. The thermostat, CM76RR is a cool only unit, I still need to control the furnace in that zone. I understand that the furnace control is routed through the A/C unit versus directly from the existing thermostat. If I understand correctly then I would need a thermostat that does both cool and heat (via heat pump) as well as furnace. Please correct me if I'm not understanding something. 2. The chillgrille, CM48GR description mentions it is for side ducts, mine are front and back, in this case back only. I don't know if this really makes a difference but I need to know before ordering anything. Thanks for your assistance. Tim

Jerred H.

8/3/2026

@TimW You're welcome! 1. The Single Zone Digital Thermostat for Coleman-Mach RV Air Conditioners item # CM76RR will also work with a gas or electric furnace. As well as the heat-pump on the Mach 8 Plus item # CM95MR. There's dip switches on the back you can see in the product pictures. You'll set the 2nd one to gas or electric depending on what furnace you have. 2. The Coleman-Mach CHILLGrille Air Distribution Box for Ducted RV Air Conditioners item # CM68GR is going to be the best option then. It works with straight through ducting. We don't carry a dual zone air distribution box nor do I know of one for this setup. The Mach 8 Plus item # CM95MR has the R32 refrigerant so it's currently a single zone system until Coleman releases a multizone controller.

Tim W.

8/3/2026

@JerredH Thank you; You asked where we camp, we tend to stay in the South Eastern states so summer heat and high humidity, so good A/C is a must. One more question, is the Mach 8 plus with heat pump available with 13,500 Btu? I'm a little concerned about amperage draw going from the current unit to a 15k unit. Can you tell me the difference between the 13.5 vs. 15k? Thanks again Tim

Jerred H.

8/8/2026

@TimW You're welcome! Yeah, spend a week or two a year in the gulf down in Biloxi so humidity control is a must down there. I wanted to check in with you because this is taking way longer than I thought to get an answer from Coleman. Currently, the Coleman-Mach Mach 8 Plus RV Air Conditioner item # CM78GR is the only 13,500 btu available for that series. It does not include a heat pump. I'm trying to find one that has that feature but I am coming up short. There's quite a bit of misinformation about their being one available on other sites so heads up. The item # CM78GR which is the Coleman 37203-076 does not have a heat pump and that's from Coleman directly. Other websites has this listed as having one. The Furrion Variable Speed Chill Cube RV AC w/ Heat Pump item # FR59TQ would be a solution to your humidity issue and potentially your power concerns. The variable speed compressor doesn't have that sudden surge in voltage. It does require 12 gauge wiring and a 20 amp dedicated breaker. These are getting ready to come out in 13,500 btu and 15,000 btu models as well. How important is the heat pump feature to you?

Tim W.

8/8/2026

@JerredH I agree the information out there is confusing so good to know I'm not chasing a product that isn't available (yet). The heat pump is pretty important as we're full timers and winters are mild enough that a heat pump is good for most of it. Both A/Cs are on 15 amp breakers so I'm assuming 14 gauge wire, the variable speed compressor would be nice but I can't rewire at this point. Does the mach 8 come with a soft start or is that another add on option? I'm trying to figure out how the furnace will wire into the new thermostat. As I understand it the furnace is controlled through the controller in the original A/C unit so if this one does not have a controller, what would it connect to? Worst case I could try to find the control wire at the furnace and wire directly, don't know if it would require one or two wires for this. Any advice would be helpful. We used to live in Biloxi before the casinos came in, it sure has changed since then, we still pass through or visit now and then. Thanks for the help Tim

Jerred H.

8/8/2026

@TimW You're welcome! I've heard it's like two completely different towns now. I avoid the casinos. I looked at a house off of Howard when I was down there last time. I love the area and can't eat at Felix's enough. Happy to help on the wild goose chase tracking these Coleman parts now. I would definitely say the current 18k Chill Cube is not an option with your wiring size. The Mach 8 Plus RV AC w/ Heat Pump item # CM95MR does not come with a soft start or capacitor. You can add one using the SoftStartRV Soft Start for Single Zone Air Conditioner Setup item # SSR54FR. You will need to wire your furnace directly to the Single Zone Digital Thermostat for Coleman-Mach RV Air Conditioners item # CM76RR. It'll have to operate separately from your AC's control box. The 12V control wire from your furnace hook is all you'll need.

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