Coleman Mach 6535 Basement AC Service

[AKIQPilot]

Just wanted to share my experience with servicing my Coleman Mach basement AC unit. My 6535 unit has the return plenum to the back side of the enclosure and the supply/discharge toward the rear of the coach into the ducting that runs up inside the rear cap.

We had a planned trip to Puerto Penasco Mexico this spring. We were there from April 28 till May 10th. We've been many times but this was the first time we had taken our motorhome down.

My basement AC unit has always worked very good. Blows nice frosty air and pulls 12 and 9 amps on the #1 and #2 compressors accordingly. In 2019 I had a start capacitor fail on the #2 compressor. I replaced the start and run Caps for both compressors while I was in there. Simple job that took about 30 minutes. In the last year I noticed the amps dropping off slightly on both compressors. The air was still pretty cold but the differential was less than 30degrees when it had always been pretty easy to get in the high 30's for differential before this last year. While we were in Mexico I decide to have the basement AC unit pulled out and serviced.

Edgar Olgin and his crew took very good care of me. They pulled the unit out and tested the amps of each compressor. They cleaned both condensers spotless. They lubed all the bearing on the fan motors and fans. Even the motor bearings that are impossible to see way inside the primary fan. They determined that my #2 compressor was slightly low on Freon because the bottom coil was frosting up. They carry R22 Freon on their truck. They carry the service valves on their truck. They soldered in the service valves and completed the 1 hour vacuum test and recharged my system with fresh Freon. They cleaned everything spotless and screwed the enclosure back together. They slipped the unit back in and buttoned everything back up.

The entire job took them about 3.5 hrs and I paid them $400 USD. Would have been $250 without the Freon recharge. The unit is very simple and can be removed from the coach in about 10 minutes. They set it on 2 buckets fill of sand that were the perfect height for performing the service. They didn't even disconnect the electrical because they needed to see it running as part of the service.

I will post some pictures of their work.

[AKIQPilot]

Here they have the unit out and have started the process.

[AKIQPilot]

Im struggling to post more pictures from my phone. I will figure it out and post a few more soon.

[AKIQPilot]

Here is the condenser before they cleaned it and after.



Here is how dusty the unit was before they cleaned it and after when they had their AC vacuum device hooked up testing the unit.



Here is the unit all cleaned up and serviced, ready to reinstall. The small bottle on the curb in front of the unit is the special AC motor bearing oil they use. I topped off each bearing at least 4 times while they had the covers off.

[Arch Hoagland]

Wow that was pretty dirty!

You should see an improvement in cooling for sure.

[AKIQPilot]

Here is a shot of my IR temp gun shooting the temp of the air coming out of my living room vent right over the drivers seat. The vent furthest from the AC unit. Both AC’s are running and the inside temp of the coach is 71f. This is about a 10 degree improvement over what it was before the service.



And here is the contact info for the crew if anyone is in Puerto Penasco snd wants their basement AC unit serviced. These guys also have compressors in stock. The compressors are currently on back order from every supplier in the States but these guys have the exact compressors in stock. $180usd.

[AKIQPilot]

Originally Posted by Arch Hoagland

Wow that was pretty dirty!

You should see an improvement in cooling for sure.

Yes, it was very dirty. It had never been out or cleaned before. There was a small section of the intake plenum seal that was missing. These guys had the correct type of seal material and we replaced the small section that was missing.

Removal, disassembly and cleaning of the unit was very simple. Anyone with basic mechanical skills can remove the unit and open it up. Any residential AC service tech can troubleshoot and repair these Basement AC units. The RV techs are afraid of them but an AC tech familiar with residential units will have no issue with a repair.

Duner has a very good writeup on how to remove the unit. I read through it several times and after watching these guys do it one time I realized how easy it was. Literally out and on the buckets in under 10 minutes.

[SuperDad]

Great info! I just bought a 2006 Itasca Suncruiser 38J yesterday. Pick it up Thursday. Look forward to reading about any upgrades you do to yours.

[AKIQPilot]

Originally Posted by SuperDad

Great info! I just bought a 2006 Itasca Suncruiser 38J yesterday. Pick it up Thursday. Look forward to reading about any upgrades you do to yours.

You will love it. One of the best floorplans ever offered in a gas powered coach. Like any RV you have to keep up with the little things but overall a very solid coach.

If you don't already have one you need to invest in a Scan Tool so you can actively monitor critical engine parameters. There are many good ones available. If you need more info just ask.

One thing to pay very close attention to is the driver side front slide out. Depending on prior use this is about the age where the slide bearings start to fail. An experienced shop can replace all the slide bearings in about 4 to 5 hours. The bearings are teflon and cost about $80 for the complete kit. The HWH hydraulic levels may also need attention depending on how the previous owner treated them.

We have lived in our 38J for 7 months out of the year for the last 5+ years. If you need help with something or info about anything send me a PM and we can exchange numbers. I have quite bit of experience with your exact same coach.

[Wild Card]

Wow! 32* out of your duct work. That's really not a good situation. R-22 with 32* supply air on medium temp is not right.

Also you say you were low on charge? Did they find a leak? It just doesn't evaporate in a sealed system.

[AKIQPilot]

Originally Posted by Wild Card

Wow! 32* out of your duct work. That's really not a good situation. R-22 with 32* supply air on medium temp is not right.



Also you say you were low on charge? Did they find a leak? It just doesn't evaporate in a sealed system.

The held the vacuum test for 1 hr and it held good. There probably wasn't much if any freon missing.



My AC unit has always blown very cold air out of the vents for 16 years. The coach is very dark and has no problem maintaining hi 70's inside when it's 100f outside in direct AZ sunshine.

This is pretty typical. About a week before the AC unit was serviced.

[Ray,IN]

re: condenser coil dirty. The owners manual and RPV manuals all say to use the green fiber "filter" so it won't restrict return air flow. Well, I can't live with that having COPD; so I began using Filtrete brand dust filters.
At first I had to replace the Filtrete filter once a week, it would become matted with dust and dirt. After a month I could extend filter replacement to 2 weeks, then 3 weeks. Now I replace the Filtrete filter once a month of full-time living. Using a mechanics mirror on a stick I can see my condenser coil and it is staying surprisingly clean.
I can sleep easier and breathe easier now too.

Like you, my basement air conditioner/heat pump performs very efficiently.

[ftodaro]

I pulled the Basement AC on my 21 year old coach about two years ago. It still works great. I just wanted to clean the coils, test the amp draw and lube the motors and the fans bearings. Even if your basement AC works fine, you should pull it to give it a good clean and lube, IMO.

[Seacrazy]

Originally Posted by ftodaro

I pulled the Basement AC on my 21 year old coach about two years ago. It still works great. I just wanted to clean the coils, test the amp draw and lube the motors and the fans bearings. Even if your basement AC works fine, you should pull it to give it a good clean and lube, IMO.

When you pull out your basement AC and reinstall, are you able to do it without removing the rear bumper ? My 01 Journey is held on with epoxy, which I would prefer not dealing with.