DIY Motorhome AC Replacement: Feasibility, Challenges, and Key Tips

[jymbee]

Yours is now 14 yo and the identical unit may no longer be in production or simply not in stock anywhere. Then the brand maker will probably say something like "Model xxxx-yz is now the replacement for that" and the fun begins...

Last year when I had dealer/repair shop do some work I asked them about replacing the front AC. Way back when we bought this coach the inspector noted that the output was only fair (my words).

I remember they could only find one dealer with that model but can't remember whether even then it was an exact replacement. I'll do as suggested here and get the specs off the actual unit and see if it's still out there.

Admittedly other than cleaning the interior filters we haven't actually had the unit cleaned properly. I guess it would make sense to do that and see if makes enough of a difference to get by for another year or two. BUT, from all I'm reading, given the age it's about at the end of its lifecycle anyway.

 

[Gary RV_Wizard]

Except for extreme cases, there isn't much to clean on a rooftop a/c unit. The external fins don't typically clog up but it doesn't hurt to rinse them out with a hose and to straighten any fins that may have been dented. The interior heat exchange also stays clean enough if there is a filter on the air intake, but running a vacuum over it can't hurt either. But you shouldn't expect much improvement. If any.

Measure the temperature difference between the air near the a/c interior air intake and the chilled air that blows out the vent.. A 20 degree differential is good performance. 15 is mediocre but any less that that is poor.

Air flow is important too - make sure enough air is passing through the chiller. You may be surprised at how much of the actual air path is blocked by dangling wires, electrical boxes or whatever.

As for age, these a/c units mostly work until they don't. A failed one either can't get the compressor started or loses cooling altogether. Gradual loss of chilling isn't the typical mode of age-related failure.

 

[PancakeBill]

It has now been more than a month since last reply, What happened? Did you do it yourself or did you have it done? I have done both, on one rig I paid the mobile guys to procure the new unit and install it. On 2 others I installed myself, one getting it on the roof myself, and in the last case had a mobile guy willing to get it up there for me. I would not recommend the method used the first time when I put it on the roof myself, I did it and I didn’t die, but I had a moment when I realized the possibility.

 

[garyb1st]

Our 2005 Pace Arrow has two AC units with heat pumps. Probably similar to yours. The larger one stopped working more than a year ago. Dealer told us it needed to be replaced. Since it was still winter we decided to wait. Several months later, on a trip to Texas, we had another issue and called a mobile repair guy to come out. While he was there, we asked him to look at the AC. He opened the cover, found and removed a piece of styrofoam that was stuck in the unit. After that, the AC worked as always. Today 10,000 miles later our AC continues to work great. That saved us more than $2,000 for a replacement.

Not sure if the dealer even looked at the unit and simply decided it was old (at the time the Pace had about 75,000 miles) and needed to be replaced. He previously told me I needed new brakes and rotors for the Pace. A heavy truck service facility told me the brakes needed to be replaced but the rotors were fine. I don't use the RV service center anymore.

 

[Gary RV_Wizard]

Not sure if the dealer even looked at the unit and simply decided it was old (at the time the Pace had about 75,000 miles) and needed to be replaced. He previously told me I needed new brakes and rotors for the Pace. A heavy truck service facility told me the brakes needed to be replaced but the rotors were fine. I don't use the RV service center anymore.

Many RV service centers don't do any real diagnosis and pretty much just swap parts based on probabilities. And profit, of course. There are a variety of reasons for that, most of which make sense for the dealer/shop but maybe not so much for the customer:

• Accurate diagnosis requires real skills + experience that (sadly) few RV techs really have. Skilled techs are hard to find (and keep) and expensive to employ.
• Diagnosis also takes time, sometimes quite a bit of it.. That's something that customers hate to pay for, especially if it ends up being an inexpensive part or fix. $200 to replace a 25 cent part never goes down well, even if it saved a $1000 replacement. And if the diagnosis still results in an extra $200 on top of that$1000 replacement, the extra labor cost hurts even more.
• In the camping season, most shops have a huge backlog of work. They want to turn the job out quickly, both to free up the service bay and get the rig back to the customer.
• Parts are profitable, and if the part turns out to be not needed, it's the customer's $$ that were being gambled. Maybe rationalized by "it was old and probably would have failed soon anyway".

 

[Kirk]

Accurate diagnosis requires real skills + experience that (sadly) few RV techs really have. Skilled techs are hard to find (and keep) and expensive to employ.

I have looked at several RV tech courses and none of them taught basic electrical principles or mechanical principles. They either assume that you have them or just touch on enough to get the people through the course. I began my electromechanical technician career with 16 weeks of basics the Navy, followed by some very closely supervised on the job training. RV tech schools do not have the time or budget to do that sort of thing. That makes any diagnostics less likely to happen and if they do it will take longer. Most RV techs use very basic multimeters, if they use one at all. Making matters even worse, some RV shops pay the tech a commission on parts that he uses and so encourage their use. They also typically pay the techs on a flat rate by the job, so he makes most money when he uses parts and very little time.

In my experience, the independent RV tech who is not part of an RV sales organization is nearly always the most skilled and the best at what he does. And most of them also charge by the actual hours worked and not a flat rate system. The same is usually true of a service only RV shop.

 

[gwinger]

I have looked at several RV tech courses and none of them taught basic electrical principles or mechanical principles. They either assume that you have them or just touch on enough to get the people through the course. I began my electromechanical technician career with 16 weeks of basics the Navy, followed by some very closely supervised on the job training. RV tech schools do not have the time or budget to do that sort of thing. That makes any diagnostics less likely to happen and if they do it will take longer. Most RV techs use very basic multimeters, if they use one at all. Making matters even worse, some RV shops pay the tech a commission on parts that he uses and so encourage their use. They also typically pay the techs on a flat rate by the job, so he makes most money when he uses parts and very little time.

In my experience, the independent RV tech who is not part of an RV sales organization is nearly always the most skilled and the best at what he does. And most of them also charge by the actual hours worked and not a flat rate system. The same is usually true of a service only RV shop.

Sounds like the people working on the assembly line. None of them know the basics, especially with the electrical assembly.
But then again, they are paid by the number of units produced, not the quality.
I went to a tech school for electronics. Half a day studying theory and a half a day hands on. We also learned that the theory was not always true!
BTW, the school was 21 months straight through. Basically three years of learning compared to most schools.

 

[John From Detroit]

Accurate diagnosis requires real skills + experience that (sadly) few RV techs really have. Skilled techs are hard to find (and keep) and expensive to employ.

That's one of the things I liked about my RVGIRL (That is the license plate on her service van) Rachel Nordstrum.

She appears know her business and if she does not... She learns and/or follows instructions.
(As do I)

Oh. I'm a certified Electronics Tech.. IN one lab class we built an RF osculator then modulated it thus making a very very low power AM transmitter (Range likely the room) and looked at the scope trace..> Something looked .. a bit. strange to me on the scope. Being a ham I fliped a couple of wires around on the scope so instead of X being time X was audio level (Voltage) Sure enough.. Something was strange (Superimposition not modulation) Also figured out why and fixed it. One way to get an "A".

(Superimposition shows up as parallelogram. Opposite sides parallel. Modulation shows up as a Trapezoid Bigger on one end than the other. For those who do not know) Perect 100% modlation is a triangle but a good thing to avoid a you go over you "Splatter"

What is splatter? Throw a rotten tomato at the wall... That's splatter Same Or how it appears on the Radio Spectrum.

 

[CharlesinGA]

I am amazed at the abundance of new A/C choices on the market now. The RecPro Houghton units are Australian design, made in China and this seemed to kick off the China made RV A/C units flood. They are all nice looking, well made and well designed and beat out Dometic or Coleman by a mile. Many of the others are made by Gree including the TOSOT unit (NOT for ducted installations). They are all reasonable priced and going by the specs and what others have said on forums, are quiet and work well.

I replaced a 11K Dometic Penguin (aka "jet engine") with a 9.5btu Houghton 9500 model that is 30 lbs lighter and MUCH quieter and puts out at least as much cold air as the Penguin did before it broke a refrigerant line. (YEA!)

There are some made for ducted installations, and many that are regular ceiling distribution plenum units. Most are available as heat pump units also and most of these are inverter driven for smooth, quiet operation.

This market has really changed in the past couple of years.

 

[PancakeBill]

IN one lab class we built an RF osculator

You built an RF kisser? I know what you meant but the word rang a bell and checked. If you get kissed by RF it hurts!

 

[jymbee]

It has now been more than a month since last reply, What happened? Did you do it yourself or did you have it done?

Neither actually. Decided that, for me anyway, not a DYI job and as the AC is actually working if not a peak efficiency, we will see how it goes and this winter when we're in the area of some RV techs we've worked with before and really like, consider our options at that point.

Our travels pretty much take place in the winter months so we don't encounter that much really hot weather. Not uncommon of course but probably just as common as the snow we sometimes run into-- in Texas even.

 

[Kirk]

Decided that, for me anyway, not a DYI job and as the AC is actually working if not a peak efficiency, we will see how it goes and this winter when we're in the area of some RV techs we've worked with before and really like, consider our options at that point.

Sounds like a valid decision. Some jobs are just not worth what it takes to do it yourself. The important thing is knowing when to get qualified help.