Old Coleman Mach A/C Changeout with Furrion Chill HE15k

[AppliedThinking]

I am in the process of changing out our old Coleman Mach A/C units. I have decided on the Furrion Chill HE15k units as they had good reviews. We also wanted to integrate Heater strips into the new units to make use of electrically powered heating capability.


First off, I removed the old units from the roof. We had the RV re-roofed with sprayed epoxy (something similar to the Rhino sprayed truck bedliner). I am now noticing that the outer coating of the silver colored spray is flaking off leave the epoxy undercoat exposed in areas. I also notice that the folks that did the work did not put the aluminum foil around the ducted vents properly and it was blocking the air flow on all the vent openings. Not to mention the the wiring was dangling with zero wire management. Poor workmanship for sure. The fix is to remove all the old ducting foil and replace with new foil allowing smooth air flow to the ducts. I am also going to go with the 8430A6321 | Coleman-Mach Lateral Ducted ChillGrille Ceiling Assembly for both locations. Lastly, I am dressing up the loose wiring that passes through the penetration and A/C control box. Hopefully the Coleman ChillGrille kit will contain the blocking wall between the intake and outgoing air distribution ports.


Second, We did purchase the Coleman adapter kits for the Furrion units. This would allow us to use the existing wiring and thermostats. This will work for A/C cooling only. Realization was that the new Heating strips could not be used with the existing Coleman control boxes. Back to e-trailer to order the new Furrion single zone control boxes and thermostats for each unit. Not a bad decision since our old control boxes are 26 years old anyway. I can still use the old boxes/thermostats until we receive the new Furrion ones for cooling.


Third, both shipped Furrion units had damage to the top shell cover and the guide pins on the bottom shell frame. e-trailer authorized replacement but the units would not get here in time for our state beach camping trip. Hard decision, I opted to not change out the whole units because of the time constraints and just ask for the top covers. Both tops had sheared side mounting tabs and cracked corners. The bottom frame, which contains all the A/C parts only had broken guides (4 on each side) to contend with. I addressed this with 16ea 1-1/8in aircraft aluminum dowels glued in with JB Weld epoxy for Plastic. Care must be taken not to get glue in the micro ridge that mates with the top cover. Now, the guide pins are 10+ time stronger that those plastic guide nubs. Perfect.


So that is the status at this point. Hope to get the new A/C units on the roof tomorrow and get them hooked up to the old Coleman control boxes for testing. Not to mention cooling off the rig so that I can finish my supply power wiring, which is on another thread, while cooking inside a hot RV.


ps. Thank you to Kevin Caudill for his youtube videos. I found them very informative and played into my design decisions.

[AppliedThinking]

Email to Furrion Tech support.
Subject: What is the correct Furrion Single Zone Control Box for Heat Strip add-on?

I have purchased 2 new Furrion 15kHE A/C units to replace our old Coleman Mach RV rooftop units. The installation went well but had to purchase two new A/C mounting frames. We also purchased the Coleman adapter kit. Both new A/C systems are operational.

We moved forward by purchasing 2 Heat Strips FACR15HESA-BL. These were mounted to the new Furrion 15kHE. We were told that we would have to replace the old Coleman Control Boxes and Thermostats. We purchased 2 new Furrion FR86NR Single Zone Control Boxes and Thermostats. What we received was FACC10SA-BL Control Boxes. These do not have a Heater Strip internal power connection nor the DIP Switch selection discussed in your Page 14 of the online Installation Guide. The only thing that suggests heating from the FACC10SA-BL Control Boxes are the 2 brown 'furn" marked leads.
Ref: https://cdn.accentuate.io/1938928631...3198785776.pdf


The burning question is; what is the correct FR86NR Single Zone Control Box(s) (WITH the Heater Strip option)? In addition, there are no manual controls on our new Coleman ChillGrille(s). It would be assumed that functional switching would occur from the Furrion Thermostats independent for each zone over the modbus data link.


Please advise all available options to get these new Heater Strips integrated.



Will follow up if and when I get a response from the tech support.

[AppliedThinking]

Part 1
After several back and forth emails with Furrion Tech dept,
I finally got a straight answer as to the correct control boxes and thermostats to be uses with the heating strips.
You only need one Multi-Zone Thermostat but I like the fact each thermostat had a temp sensor at the base.
2ea Control Boxes: FACC12ESHA-BL (2021132273)
2ea Thermostats: FACW12APZA-BL (2022068580)

I spent this last weekend installing the new digital control boxes and repurposing the old analog wires.
Starting with the forward A/C unit. First was to remove the old analog thermostat and control boxes.
Once all the stuff is out of the overhead, I re-torqed the hold down bolts to 45in/lbs. Also installed lock nuts.
This was really needed as there was light evidence of water dark spots on the grille. Highly Recommended.

The new Thermostats do not need the 12VDC supply so they are capped off.
Instead the new control boxes have the 12VDC supply which I tapped of the Yellow/White lighting leads that are in the opening.
The existing Gray, Blue, Yellow and Green wires were re-mapped to the A, B, +12 and GND digital bus lines.

The bug in the soup is that the old analog propane furnace lines are located in the forward thermostat area.
The new Furrion furnace leads (brown) are in the overhead. There must be a wire trough going forward to rear and
the short conduits are not continuous. There is no way to fish in new conductors with a tape.
The only option is to use one of the existing conductors to pull in 3 new lines and hope the main trough is not tie-wrapped.
This is a two person job to feed and pull one inch at a time. The risk of breaking a conductor while pulling is valid.
There are could of other options: Leave one of the old Coleman thermostats in place for just the heater.
Two put in a simple timer switch to power up the furnace.
Frankly speaking, we do not use the propane furnace other than in locations without a hookup.

The forward Control Box was assigned Zone 1 and the rear Control Box was assigned Zone 2.
Used a 7 conductor #18 sprinkler cable for the front to rear thermostat digital bus. Ran this throught the hallway closet overhead.
I can control both Furrion A/C units with the heating strips with one Furrion Multi-Zone Thermostat.
I still like the idea of two thermostats in case one of them goes south. My first one was defective.

Below is a pic of the completed Furrion Control Box mounting. I use heavy duty Velcro strips between the styrofoam and the box.
I did use the trick to get the velcro by spraying a couple of layers of 3M Super 77 Multipurpose Spray Adhesive first. Works!!

Still more to do to finish up the project. Figuring out the RV Propane furnace is at the top of the list.
I am happy with all the feature the new digital control provide (Multiple fan speeds and auto, lighting and programing....).

Hope you find this write up as useful. It is a adventure after all!

[AppliedThinking]

Well it looks like I cannot post the pic. No biggie

[AppliedThinking]

All the Furrion digital controls are functional with both zones 1(front) & 2(rear). I have completed the final torque check on the rear A/C, above the master bed, and it is buttoned up. Will do the same for the zone 1 A/C unit today. BTW, there was a few turns needed to bring the rear torque into spec's at 45in/lbs. Yes, I do use locking nuts(1/4-20 SS) as well.
There is no way for me to fish in new conductors to use the Furrion furnace relay. So that means the Suburban SF-35 furnace needs to be a stand-alone system. Hindsight, I did not take enough detailed pic's of the existing analog Coleman Mach TSTAT. I do not think that I can use a mechanical timer switch either at this point. So, it's back to using one of the old Coleman analog TSTAT for just the furnace control. I did validate that the Coleman analog TSTAT White lead does go hot +12vdc when one put the TSTAT in Heat mode. I am going to assume that this switched circuit goes to the furnace delay relay. There are different color codes that each manufacturer uses, it's hard to keep track unless one maps the circuit out.


Suburban to TSTAT:
Red (+12VDC Positive)
Blue (-12VDC Negative)
White (Gas furnace Trigger +12VDC)



It's not working at the moment and need to check the fuses for opens.
The Journey continues....

[AppliedThinking]

I made the decision to retain one of the old Coleman Mach TSTAT.
This will operate the Suburban SF-35 propane furnace in times where there is no hookup for the Furrion Heating Strips.
Very simple,
TSTAT config:

Red = +12vdc Positive power
White = Furnace control
Blue = -12VDC Negative power


That's it! Done

[AppliedThinking]

One of my Furrion Multi-Zone thermostats was defective, and for a while I controlled both zones with one thermostat. I just installed the replacement yesterday and both are operational. I did see moments where they were going back and forth to take control. I did not see any Master/Slave Multi-zone control configuration.

I did not know about only one 12VCD supply. I did apply 12VDC to both control boxes(redundancy is not a bad thing).

Unfortunately my RV wire runs prevented me from fishing in two more conductors for the Furnace connection. So I remounted one of the old analog Coleman Mach thermostat for just furnace heat only. Both forward and rear Heating Strips are operational. However, it does take some time for them to warm up.

One other thing to note, is the torquing of the A/C units' hold-down bolts. I would recommend that these be done at a minimum of 3 stages with a few days apart. Each torque session did indeed take a few more turns to get them down to 45in/lbs. I also included a 1/4-20 SS locking nut to prevent them from coming loose over time. For me, I did separate 3 torque sessions over a couple of weeks. Each torque session did result in a few turns.

Finally for my installation, I did not use the Furrion air distribution grille. I preferred the Coleman Chill Grille as it has more air flow options. Mounting of the A/C control boxes was done using heavy duty velcro strips above the lip. The only way to get the velcro adhesive to stick was to use 3M 77+ spray adhesive on the styrofoam. Mounting the control box above the lip worked perfectly and all interface plugs and socket had plenty of room. Not to mention, it was easy to dress up the interface wire runs for minimal interference. Those control boxes are very solid now.
I may look into a third party RGB lighting solution later down the road.

The only other project in the mix is repurposing the rear fold down analog TV table. The idea that I came up with is to reuse the 15x15 cut-out for recessing a TV wall mount allowing a LED TV to sit flush against the wall in a vertical position. There are newer wide screen HD TV's that will operate either horizontal(default) or vertical portrait mode. The theory is to store the TV vertically thus allowing for a larger screen display since the area, for me, is 21in wide. To be honest, we have never used the rear master bedroom TV but with granddaughters 2 & 4 it may be great for some quiet time. ha ha.

Furrion change out complete. Pic's available if desired

[AppliedThinking]

A couple of pics