Basement AC is dying

[Muttibear]

Our 2003 Adventurer has basement AC. We had mechanic look at and he says its dying - or maybe already is dead! He suggests getting a new roof AC. Anyone had experience fixing a basement AC or other suggestions? Thx!

[rgvtexan]

Try a HVAC guy!
Lot of help here https://www.google.com/search?q=baem...nnieowners.com

https://www.google.com/search?q=base...earch=irv2.com

[BobC]

Originally Posted by Muttibear

Our 2003 Adventurer has basement AC. We had mechanic look at and he says its dying - or maybe already is dead! He suggests getting a new roof AC. Anyone had experience fixing a basement AC or other suggestions? Thx!

First, it should be obvious whether it's dead or not. It sounds like your "mechanic" isn't familiar with these units, hasn't really done any troubleshooting and is looking for a buck by installing a roof unit. Replacement with a roof unit isn't unheard of but not the best option. Personally, I wouldn't deal with him any more. "Mechanics" are not air conditioning repair specialists.

These units are very repairable if you can find someone who's knowledgeable. There are many things, like a bad "start capacitor" or "run capacitor" that are inexpensive and easy to fix even by a DIYer. It could even be the thermostat.

They're also replaceable with a unit cost of about $3k + installation (admittedly not cheap). Some have had to do some modification of the return air attachment to make the current replacement model fit. I think this is much preferable to a roof unit although others may differ.

I suggest you give us more info on what you're experiencing and we should be able to help you figure this out..

Here's a video that may give you some hope:

https://www.youtube.com/watch?v=dTq7LuWHihU

There are numerous threads on Winnieowners about these units so you should do a search and educate yourself. If you put "Basement Air" or "Basement A/C" into the search box at the top of the page, you'll find a lot of reading material. Don't be overwhelmed, most of these are by DIYers. Don't dwell on the details. The point is they can be, and are worth repairing.

One final thing. These units are very similar to small residential units, especially those installed in mobile homes so with some searching, you may be able to find a local HVAC shop that repairs mobile home units who is willing to help you out.

And, above all, stay away from RV dealers. I'd also call every independent RV repair person in your area and ask them if they repair "Coleman Basement Air" units. Do this after you do your research so you have the basic knowledge to tell if they know their stuff or not.

[Morich]

When I get that sort of answer from a tech, I really begin to get a bad feeling that they assume there is just no way I would begin to understand what they are talking about!!
And that is the first step to them really getting in my pocket as they can believe I know nothing and will not question what they say I need to do!
Step one of your AC dying is to ask what they mean as the thing is just a collection of parts and most of those parts are easy enough to change, so what part is going bad????
If it is working and they can't tell me what is wrong, I move on!

I would not be inclined to devalue the RV so much with a rooftop AC and hauling a large load of junk it the back with the old one. If the fan motor is going bad like bad bearings, those bearings or the whole motor can be changed pretty easy, but only if they are not trying to sell you a whole new unit!

We live in a world where it is common to first try to sell you a big story and then if you refuse that, they may come around to the real truth.

Lots of forum discussions on fix and repair of AC.

[toewsrus]

These basement a/cs are repairable. I'd certainly think twice before I cut a hole in my roof!


I just purchased a 2005 Journey with a basement a/c and am having trouble too, it won't keep the coach any cooler than 5 degrees below the outside air temp (90 outside, 85 inside). Based on my infrared thermometer, visual inspection, and some research here, I believe my duct is blown open behind the coach's rear cap. Today I disconnected everything but the top roof screws. We'll do that Friday if it doesn't rain, and pull the whole rear cap off to repair the duct work. While I have it apart, I'll probably check the systems out to make sure they're running optimally.



I have records that one of the compressors was changed two years ago, so I know parts are available and some technicians have the knowledge to do the work. I believe the answer lies in whether they want to be bothered to do it or not. Plus like someone mentioned above, there's lots that can go wrong with basic generic electrical parts that any good technician would have on their truck. If the guy didn't even look at it to troubleshoot it, find someone else.



Here's a photo of our rear cap sweating in the humidity while running the a/c.
I've never pulled an RV apart like this, but was an Air Conditioning Tech and Service Manager in another life. Not to mention, I love doing everything I can myself.

[imnprsd]

OP: Your mechanic is not stupid. He's just not very familiar with your RV and/or he maybe trying to soak you.

Specifically, IMO, if anyone declares your basement AC is dead, without first doing a visual inspection, then checking your RUN and Start Capacitor values are in spec, and then checking your Hard Start Kit PTCR is working properly, just walk away.

Now if your mechanic did this, then he may know what he is talking about, but you also have to tell us what your symptoms are before we can help you further.

=== BASEMENT AC SERVICE NOTES ===

For less than $75 in parts, if you need them, you maybe able to fix your basement AC yourself.

And if you don't know how to use a multimeter to check your capacitor values, you can still do a compete service yourself, with no understanding of what you are doing, for $150 in parts, so long as you turn off your power, and just start replacing one component at a time -- so you don't mix up any wires. It's easy. You will see.

HOW TO FIND MORE THREADS ON THIS SUBJECT

Just type these words in the search bar above -- and start reading up on this subject:

"imnprsd coleman mach"

or google imnprsd coleman mach site:winnieowners.com

Further, I would never buy an RV without a basement AC. And if you want more cooling check out these upgrade...

Search for "imnprsd 8000 portable ac upgrade"

or again google imnprsd 8000 portable ac upgrade site:winnieowners.com

Note: I really like the RV Expert videos (see posts above), but this one is moves so fast it left me more discouraged at first. I.e., I found out, you don't need to be and RV expert to do a full service on your basement AC. If fact, I think almost anyone can service their basement AC if they just know what to do.

[catmandoo62]

when i bought my 99 grand tour vectra notes in receipts said that the primary compressor was locked up so they wired up the secondary to run so i only had one compressor.second time we took camper out it got up to 100 degrees and it was hell.my wifes sisters boyfriend is an hvac tech so he said to pull the unit and he would check it out.and i was dreading that job,but i had the whole unit out in about an hour.he took it to their shop and replaced the bad compressor and recharged and while apart found that one of the fan brackets was broke and the squirrel cage ate into the side of the housing,which made sense as it always had a medium vibration to it.but after welding that bracket back that fan blew twice the air as before.so yes these can be repaired,the compressor was 400 some bucks time i was done i had about 600 in it.

[imnprsd]

I think the industry talked-down these basement ACs, because Winnebago wanted to go with less expensive rooftop ACs, back in 2010, and they wanted to kill the Onan 7500/8000 line of generators.

The two (AC & Genset) are very related to one another, because it takes a higher amp generator to handle the 45-55A compressor "inrush" current.

The Coleman-Mach is a very solid box; and as long as you do NOT ignore the warning signs the compressor will outlast the metal.

Moreover, outside of forum communications, where would an owner go to know what symptoms to look for? And no where else can you find information on the type of maintenance you should perform.

I now will check my basement AC every 3-4 years to make sure everything passes a visual inspection; and my Start & Run Capacitors are within spec.

I also have to say, but I don't know this for sure, it seems to me there are far fewer RV parks out there with dangerously low AC power than was the case 10-20 years ago. That said, so long as you run your Coleman-Mach on "good" AC power, your compressors will run for many, many years.

**** So now, I always double check the shore power voltage before I plug in; and I monitor it inside my RV as best I can; and I monitor the power even more on hot days, when everyone is running their ACs. And when an RV park is full I really watch for "lower voltage" conditions as the park draws down the voltage off their low-end transformer on the power pole. ...And one more thing. When I know a lightening storm is approaching, I unplug my RV power cord from the shore power post and run on generator power if I have to.

catmandoo62: Do you have any information on where to buy a replacement compressor? ...Or did you overhaul your Coleman-Mach more than 10 years ago and that source is no longer available?

[BobC]

catmandoo62: Do you have any information on where to buy a replacement compressor?[/QUOTE]

I'm not catmandoo62 but replacement unit is currently available. It's an Airxcell/Coleman 46515-811 and is available from multiple sources. I started looking at these about three years ago and the price has gone up from $2k+ to $3k+. I still need to troubleshoot mine some more before I decide what to do. Also, when I was looking (I forget which vendor), the replacement unit specified 50A service while my 2002's unit was spec'd to run both compressors on 30A, depending on what else was using power. I called the vendor and was told the new unit would also run on 30A but they were spec'd at 50A to avoid complaints:

https://www.google.com/search?q=Airx...4dUDCA8&uact=5

Here's a thread on replacing the unit. Note that the original poster in this thread had an issue with the return duct location. His MH, a Diesel pusher, required the return duct on top due to his rear engine, while the replacement unit's return duct is on the back. I took a look at the parts catalog for your MH and it shows a rear return duct so you shouldn't have the problems that the poster had. Nonetheless, it's an informative thread. You should, however check all the measurements.

Parts Catalog (see pg 167-161): https://www.winnebago.com/Files/File...GO/3wfg33v.pdf

Replacement Thread: https://www.winnebago.com/Files/File...GO/3wfg33v.pdf

And here's a good step-by-step document on repair, removal and re-installation:

https://www.rvforum.net/miscfiles/Ba...attredirects=0

[imnprsd]

Since these basement ACs are really like having two ACs in one, I can see how spending $2,000 is a very good deal to get all new components.

The efficiency of the older R22 should be better than the newer R134a, but I'm sure these newer ACs have larger compressors to make up for that.

Too bad they don't pull less amps, but that's not necessarily a problem for an Onan 7500/8000 generator.

What I would be ecstatic about is if Coleman-Mach (RVP/AirExcel) would but a "Soft Start Kit" in these things instead of using a cheap "Hard Start Kit," but they won't.

I also hear 134a will be phased out by 2025, just like R22 got phased out. So it won't be long before you start seeing a "fire sale" by the distributors, but at some point after that these AC will get more expensive. TBD.

DO YOU WANT MORE AC COOLING IN YOUR RV?

* Have you got a 14" wide cabinet under a window in our front cabin?

If so you might want to hide a portable 8,000 BTU AC inside and boy will that make a difference!

For more information, type "imnprsd 8000 btu ac" in the Winnie search bar above; or type this in your google search bar:

imnprsd 8000 btu ac site:winnieowners.com

[catmandoo62]

imnprsd: let me see if i can find the invoice,i know the part number on the compressor got changed. if you can get to the compressor and read the part number and do a search for it it will come up with the new number.

[catmandoo62]

well had my unit out camping this weekend and had a couple issues,first is it was awesome on the first compressor,smooth and quiet,BUT when the second kicked in it had a vibration and an intermitant rattle.bugged the heck out of me SO today i pulled the a/c out AGAIN and found that when he replaced the compressor that the 3 mounting holes were closer together then the original so he used one of the studs and drilled holes for the other 2 and ran bolts in from the bottom.but the problem there is he didn't drill very straight so those 2 were binding and the compressor couldn't shake so to speak on the rubber isolators,and a line was right up against the bearing hub of the blower.so i drilled the holes out a little bigger this pulled the line away from the blower and now it has movement on the isolators,i also noticed the top sounded rather tinny so added a strip of foam rubber on top of the condensor and that cured that issue.so tomorrow i am going to cut an acces hole in the side cover next to the compressors as when he replaced the cpompressor he added ports to fill and check pressure and on my 99 grand tour i have about 8-10 inches in front of the unit between it and the lp tank so hopefully i won't have to ever remove it again.AND imnprsd here is the compressor i found. https://www.ptacsolutions.com/Tecums..._p_180020.html

[KD4XR]

When my basement AC failed two weeks ago in Las Vegas heat, I purchase an 8k BTU portable AC from Home Depot. It would not keep the entire coach cool so we put it in the bedroom and closed the door. It kept the room cool and we sleep comfortably.

I'm no expert but it seems to me that these portable AC units have an inherent problem when used in an RV. They must becreating negative air pressure inside the coach as they exhaust hot condenser air out the window vent. That hot air going out the window has to be coming from inside the coach and something has to replace it. We all know these rigs aren't air tight so that means outside HOT air is being pulled into the coach, due to the negative pressure, through every bad seal, crack, or crevice replacing the hot air going out the window vent. And along with that outside hot air comes dirty air including generator exhaust.

[Ray,IN]

IMNPRSD, The MH industry stopped using the basement unit when the mandated engine emissions requirements took effect. There was just no other space to put the emissions stuff without reducing basement storage area.
Muttibear, there is a wealth of information on irv2.com Winnebago forum about rebuilding your basement unit. "Duner" even has a pdf tutorial with pictures showing how to remove and service a basement unit. Replacement parts are available for all basement units. One man even fabricated a new exterior box to replace his rusted out box.

[Ray,IN]

Originally Posted by KD4XR

When my basement AC failed two weeks ago in Las Vegas heat, I purchase an 8k BTU portable AC from Home Depot. It would not keep the entire coach cool so we put it in the bedroom and closed the door. It kept the room cool and we sleep comfortably.

I'm no expert but it seems to me that these portable AC units have an inherent problem when used in an RV. They must becreating negative air pressure inside the coach as they exhaust hot condenser air out the window vent. That hot air going out the window has to be coming from inside the coach and something has to replace it. We all know these rigs aren't air tight so that means outside HOT air is being pulled into the coach, due to the negative pressure, through every bad seal, crack, or crevice replacing the hot air going out the window vent. And along with that outside hot air comes dirty air including generator exhaust.

That is why one should always buy a portable with 2 hoses, one intake, one exhaust.

[tim myers]

I have read through most of this thread and have the Coleman Mach basement AC unit, I love the way it works and especially how it works with the Basement Furnace when Outside Temps are too low for the Heat Pump function. Here is my question. I always hear a bit of vibration on start up of the fan, not sure if it is the Condenser fan or the Evaporator fan, also I have always had good luck running the basement on one compressor when plugged into a 20A circuit at the house. Just this past week I have had issues with the single stage of cooling running at a higher amperage than what I am used to seeing, Normally on the first stage of cooling I will see 17 to 18 Amps. Just last week the first stage of cooling has shot up to 22 - 23 amps, which will eventually trip the breaker in my house. Would either or both of these issues be caused by the start or run caps starting to fail?

[KD4XR]

Originally Posted by tim myers

I have read through most of this thread and have the Coleman Mach basement AC unit, I love the way it works and especially how it works with the Basement Furnace when Outside Temps are too low for the Heat Pump function. Here is my question. I always hear a bit of vibration on start up of the fan, not sure if it is the Condenser fan or the Evaporator fan, also I have always had good luck running the basement on one compressor when plugged into a 20A circuit at the house. Just this past week I have had issues with the single stage of cooling running at a higher amperage than what I am used to seeing, Normally on the first stage of cooling I will see 17 to 18 Amps. Just last week the first stage of cooling has shot up to 22 - 23 amps, which will eventually trip the breaker in my house. Would either or both of these issues be caused by the start or run caps starting to fail?

Mine started making those noises during startup and while running just before the blower motor failed.