Coleman Mach Basement Air Unit Capacitor Repair

[AKIQPilot]

Originally Posted by Greatscot

I agree about James, RV Expert is the name of his shop. He also installed a Grade Brake on my Allison 1000 since my MH is a 2004 and Allison didn't include the grade brake until 2005.

Where is his shop?

[FIRE UP]

Tom,
I again want to thank you for taking the time to detail your tests and experience. I have been fortunate so far, in the 7 years we've owned our now, 14 year old '04 Itasca Horizon 36GD with the C-7 330HP CAT. Our basement A/C has done its job, even in some extreme conditions. Most of us would like to be able to hang meat in the coach, in the middle of a 110 degree day. But, most motorhomes are just not that well insulated and, have that powerful of A/C to be able to really, really lower the temps INSIDE when the temps are EXTREME outside. As you so flawlessly detailed, the color of the exterior of the coach, DOES have influence on the inside temps.

So, trying to counter that set of conditions, is pretty darn tough. Now, I suppose you could hang meat in 30' coach if you had 6, 13,500BTU units on the roof or, TWO of our basement A/C units, one in the front and one in the back. But, the rest of the city you're in would have a brown-out when you fired all that stuff up.

Anyway, enough blabbing. Nice job and I'm gonna copy and paste that stuff where I can't find it when it's really needed, when I'm doing the same kind of work on our unit, in the future.
Scott

[Ray,IN]

Originally Posted by AKIQPilot

Wow Ray. An Ecobee would be awesome. I have Ecobee stats in my home in AK. They work fantastic.

That website is up and running again.

[NoMoreAZ]

Originally Posted by AKIQPilot

For reference, my unit is a Coleman Mach 6535 Series, Two Ton Basement Air Unit.



The Run Capacitor is Part # 1499-5671. Locally this part was $29+tax.

Be careful when you order a Run Capacitor. Make sure you know what make of compressor is installed because different compressors have different P/Ns for the run caps.

Might want to get a Parts Catalog to see the different P/Ns. Service Manual has the different make of compressors shown at the beginning of the manual.

[TenMillie]

Originally Posted by AKIQPilot

For reference, my unit is a Coleman Mach 6535 Series, Two Ton Basement Air Unit.

So now that summer is basically over everywhere except the deep south.........

Compressor 2 on my Basement Air unit quit running last week. It's still nearly 100f every day in the Las Vegas area and one compressor was struggling to keep up. I was surprised by its performance but the direct sun and near 100f temps were really taxing the single air conditioner.

I confirmed it was Compressor 2 by looking at the amperage draw on my Surge Protector. With everything off except the air conditioner I was seeing 0-1 amps of load on Line 1 and about 14 amps on Line 2. The TStat was set plenty low enough to trigger Compressor 2.

I called about 4 local Mobile Mechanics and one local residential AC guy. 3 mechanics told me they don't work on the Basement Air Units. The Residential guy told me he didn't work on Motorhome AC units, even after I explained to him how it was similar to a Resi unit. The last mobile mechanic told me he was booked up for a week and that repair costs would like start at $350 and go up from there.

A non functioning Air Conditioner was something I had worried about for some time so I had read through several threads over the years. I can't say I knew what I was reading but I knew there were a few threads out there that discussed troubleshooting and common problems. Yesterday I found and downloaded the Coleman Mach Service manual for the 6535 Series unit. There is a service manual available for the 6536 Series unit on line as well. While I am not an electrician I do know how to use a multimeter and I do a fair job of reading electrical schematics.

Of course from all of the reading I had done prior I was leaning (hoping) it was a Start or Run Capacitor for the #2 compressor. I woke up yesterday morning and called two big RV dealerships here in Las Vegas and both of them had the Start Capacitor Kits in stock. Neither stocked the Run Capacitors. I checked with a local appliance parts store here and they had the Run Capacitors in stock but don't carry the Start Capacitors. So I'm thinking maybe I should replace the Start Capacitor first since it's a stocked item at the RV store.

I then began reading through the service manual to try and eliminate other reasons for the #2 comp not to fire. I confirmed that the TStat was sending 12vdc to to the control board in the unit for both compressors. I confirmed there was 120vac to all places in the unit where it was supposed to be. By noon it was getting too hot to shut down the only functioning AC unit I had so I just went to the parts store and bought the Start Capacitor Kit and kept reading.

Hard Start Capacitor Kit Part # 8333A9021 was $32+tax. This kit is put together by AIRXCEL out of Kansas. The kit has the capacitor, the motor starter, new wires, installation bracket and instructions. It says it's for the Coleman Mach Roof Air units but the part number cross referenced over to the Hard Start Cap I have on my basement unit.

The Run Capacitor is Part # 1499-5671. Locally this part was $29+tax. I didn't buy the Run Cap but they carry them locally. I will very likely pick up another Hard Start kit and a Run Cap to have on hand for the next time I find myself with less than adequate air.

So this morning at about 7am It's a nice cool 71f outside and I figured it was a perfect time to shut down all power to the unit and swap out the Hard Start Cap on Comp 2. So I shut down all power, AC and DC. Opened up the side panel. Unplugged and unmounted the #2 Start Cap and plugged in the new one. I used the same yellow wire from the original Start Cap but used the new red wire that came in the kit. The Start Cap took about 5 minutes to install.

I restored power to the coach and turned on the AC with a setpoint 1* lower than room temp. #1 Compressor started right up and began blowing cold air drawing about 14amps. While outside I had my wife lower the setpoint to about 4* lower than room temp. A few seconds later Compressor #2 started up and began drawing about 9amps. I let both compressors run for a few minutes and before long it was 67f inside the coach. I put the setpoint back up to 72 and here we sit with an AC system that seems to be functioning normal again.

I just wanted to log what I found and how I went about troubleshooting my Basement Air problems. Not every challenge is going to be this easy but anytime I can save $300+ on a simple repair I will sure give it a try.

Hope this helps someone in the future.

Coleman Mach 6535 Service Manual

AKIQPilot

I have the same unit and my #2 compressor is not starting. You say you removed the side panel. Did you remove the unit from the coach to access the side panel? I see no way to get in there without removing the unit first.
Thanks for your write up!!

[G jeffers]

Originally Posted by TenMillie

AKIQPilot

I have the same unit and my #2 compressor is not starting. You say you removed the side panel. Did you remove the unit from the coach to access the side panel? I see no way to get in there without removing the unit first.
Thanks for your write up!!

You don't have to remove the unit, it's right in front. I removed mine to install a new unit but you can see the access door on the left..

[TenMillie]

Originally Posted by G jeffers

You don't have to remove the unit, it's right in front. I removed mine to install a new unit but you can see the access door on the left..Attachment 221042

Is that where the Capacitors are located?

[G jeffers]

Originally Posted by TenMillie

Is that where the Capacitors are located?

Yes

[BCam]

Originally Posted by AKIQPilot

That is the kind of guy we need access to around this forum. He obviously knows quite a bit about RV's. I need to watch more of his videos.

Here's a link to his Youtube page with a lot more videos (not all RV related):

https://www.youtube.com/user/azrvexpert/videos

[AKIQPilot]

Originally Posted by TenMillie

AKIQPilot

I have the same unit and my #2 compressor is not starting. You say you removed the side panel. Did you remove the unit from the coach to access the side panel? I see no way to get in there without removing the unit first.
Thanks for your write up!!

Just like jeffers said. No need to remove the AC unit from the coach. You access the electronics by removing the small cover on the left side of the unit. one phillips head screw holds the cover on. You can get to the unit by removing the 4 screws that hold the side of the coach in place, then you swing that side panel up securing it with a bungee attached to the ladder.

Be careful, once you remove the small cover on the left side of the AC unit everything inside there is HOT. 120VAC and some 12VDC. Besides using a VOM to troubleshoot I wouldn't touch anything else in there until all AC and DC power to the coach is off. IF the green light in the center of the circuit board is lit then you still have 12VDC to the AC unit.

[AKIQPilot]

Originally Posted by BCam

Here's a link to his Youtube page with a lot more videos (not all RV related):

https://www.youtube.com/user/azrvexpert/videos

Thanks. I will save that link and look some of those videos over as time allows.

[TenMillie]

Originally Posted by AKIQPilot

Just like jeffers said. No need to remove the AC unit from the coach. You access the electronics by removing the small cover on the left side of the unit. one phillips head screw holds the cover on. You can get to the unit by removing the 4 screws that hold the side of the coach in place, then you swing that side panel up securing it with a bungee attached to the ladder.

Be careful, once you remove the small cover on the left side of the AC unit everything inside there is HOT. 120VAC and some 12VDC. Besides using a VOM to troubleshoot I wouldn't touch anything else in there until all AC and DC power to the coach is off. IF the green light in the center of the circuit board is lit then you still have 12VDC to the AC unit.

Yes, thank you!! I have ordered the part. Do not have a meter so I removed the old one and turned everything back on. Unit ran as it has been running for some time. Have my fingers crossed.

[bobmac]

Your best bet - if you encounter an Air Conditioner failure while on the road that you suspect is a capacitor - is to purchase locally a replacement capacitor from an electronics store, a heating/cooling parts outlet or a refrigeration parts outlet. Capacitors are a generic electronic component and what you need to know is their "capacitance value" usually in micro farads (uf) and the voltage ratings expressed in volts - typically 370v or higher. You can generally get this information from the parts list for the unit as it usually displays the part number and the capacitance & voltage rating. Generally if you find a capacitor with the correct capacitance rating, you can use a replacement with a voltage rating equal to or higher the one being replaced - but not lower. I had the capacitor fail on my indoor fan and the replacement was $2.26 from an appliance parts place. I carry replacements for all the caps for my unit and I have less than $50 invested. Good luck

[BCam]

WARNING!

Before you do anything with a capacitor (including trying to remove wires) and while it is still in place, you should short the terminals on its top to each other with a screwdriver with an insulated handle. Capacitors store voltage and can deliver a dangerous shock.

https://homeguides.sfgate.com/discha...tor-29302.html