# A/c Vibration



## RAAAT (Jun 26, 2004)

I posted this weekend about how the a/c had vibrated the mounting bolts loose. It seems there is more to it than just that. Tightening the bolts lessened the symptoms but it seems that for some reason the fan motor is vibrating badly.

As a little background, we bought this '04 23RS new two years ago. It's been out on week long outings were the a/c was used probably 8-10 times. We lived in it for three weeks following hurricane katrina - running the a/c. We've had no problem with the a/c other than having to reset it occassionally. It's kept under a fabric RV cover when not in use.

When I uncovered it and turned it on this weekend, I notived a bad vibration. I took the inside cover off and tightened the mounting bolts. I turned it on (low fan) for a second and it seemed fine. However, yesterday I needed to cool the camper and when I turned it on, I noticed it was still vibrating badly - just more muffled since I had tightened the mounting bolts.

I've ruled out compressor vibration. The vibration seems to be due to the fan. It vibrates just as bad with the compressor off. Also, it's not as noticeable with the fan on low. To give you an idea of the vibration with the fan on high, doors will vibrate, the microwave door makes noise and the aluminum foil we put under the floor vents in the summer gets pretty loud. I climbed up a ladder to look at the unit and it's vibrating so badly that it appears blury if you look at it.

I'm going to take the cover off after work, time permitting. I'm thinking that it's possible that a fan mounting bolt is gone, or, perhaps, dirt daubers have built a big nest in part of the squirrel cage. This last option seems unlikely as it has been covered.

I was wondering if anyone had any thoughts of what may be the problem.

Thanks,
Rodney


----------



## BullwinkleMoose (May 22, 2006)

I think you are getting close. Check all mounting bolts as well as where the squirrel cage mounts on the motor shaft. The set screw could be loose and the bearing on the squirrel cage could also be bad. Don't ever rule out dirtdaubers i've seen them build nest inside a closed box.


----------



## dancinmon (Oct 5, 2004)

On our old 25FBS a piece of 1/2' x 1/2" x 18" sticky back foam inside the AC unit came loose and got sucked into the squirrel cage fan. It sounded like it was going to explode until the piece that was flapping and hitting the cover broke off. After that we had a small vibration from the remaining piece still stuck in the fan. Removed the cover, took out the foam and now it works fine. Never could see where the foam came from so I didn't worry about it.


----------



## Ghosty (Jan 17, 2005)

just like a tire -- the fan can gt out f whack if there is dirt in the squirrel cage -- take a look -- maybe something built its next in it -- but it may be enough to throw it out of balance...

or i could be as simple as the bearings are shot and its time for a new one -- by the way though -- the fan is rated at something like 10000 hours of running befroe failure (mtbf) i believe ...


----------



## RAAAT (Jun 26, 2004)

Well, I climbed onto the roof of the outback to take the cover off of the a/c unit. As I removed the multitude of screws securing the cover, a putrid odor asserted itself into my senses. Consider, if you will, the smell of a rotting rat.

I discounted that the problem related to a rotting rat pretty quickly. First, I didnâ€™t see how a rotting rat could cause the vibration. Second, I recalled the last time we used the camper. A clue to what I began to believe was the source of my problem lurked in my post above. That is, I said, "We lived in it for three weeks following hurricane katrina - running the a/c".

Given that fact, and one more piece of knowledge and you may be able to guess the source of the problem. However, you would probably have to be from the Southern parts of Mississippi, Alabama, Louisiana or Florida (or possibly parts of GA or TX) to have that knowledge.

You see, there is a pest we have to live with in this part of the country. It is called a love bug. It looks a lot like a small black firefly - minus the illumination. In spite of its name, the love bug is one of the most hated insects around here. Oddly, it doesn't eat crops. It doesn't sting. It doesn't bite. It doesn't do anything overtly harmful. But, what it does do is breed. The name comes from the fact that they're always - well copulating. Believe it or not, they actually fly connected together at the privates. Now, we don't hate them because they offend us in their unbridled amorous displays. No, we hate them because of their unchecked numbers. We see a few at various times of the year but in September, millions swarm in a vast orgy for about a month. During this time automotive radiators clog, windshields become opaque and car washes work overtime. I've seen vehicles look almost furry from the accumulated remains of repeated impacts with love bugs. Worse yet, they seem attracted to anything white, e.g., the outback.

When the hurricane departed, the love bugs arrived - in record force. They showed particular interest in the outback. Bug spray, off and flyswatters only curbed their curiosity briefly. They infiltrated the camper at every opportunity. Each night was a chore of sweeping out their little spent carcasses and trying to keep clean sheets on the beds. Finally, electric service returned. We moved back into the house. The love bugs left and I had pretty much forgotten about them - until today.

So, I finished removing all of the screws and pulled the cover off of the a/c. The first thing I noticed, aside from the smell, was a moist, black, furry build up on about 1/3 of the condenser fan. The condenser fan looks like a spoked wheel - an inner hub and an outer rim with about 8 or so fan blades in place of the spokes. In the worst areas, there was about an inch build up of compacted rotting bugs between several pairs of fan blades - probably around half a pound - talk about out of balance. Anyway, a little work with the water hose and all is right again. Fortunately, the squirrel cage fan was clean - it's well secured in a very tight fitting plastic housing - unlike older a/c units where it's enclosed in screwed together sheet metal. It now runs quiet and smooth.

Lesson learned: donâ€™t go camping around here in September - unless your forced to by a hurricane.

Thanks,
Rodney


----------



## countrygirl (Apr 9, 2006)

RAAAT said:


> Well, I climbed onto the roof of the outback to take the cover off of the a/c unit. As I removed the multitude of screws securing the cover, a putrid odor asserted itself into my senses. Consider, if you will, the smell of a rotting rat.
> 
> I discounted that the problem related to a rotting rat pretty quickly. First, I didnâ€™t see how a rotting rat could cause the vibration. Second, I recalled the last time we used the camper. A clue to what I began to believe was the source of my problem lurked in my post above. That is, I said, "We lived in it for three weeks following hurricane katrina - running the a/c".
> 
> ...


----------



## PDX_Doug (Nov 16, 2004)

Rodney,

Well....

At least the problem is solved!









I have to say though, I loved reading your story! Very well written, and kept me on the edge of my seat. Maybe you should contact Pixar! Good job!









Happy Trails,
Doug


----------



## RAAAT (Jun 26, 2004)

Thanks, Doug. I appreciate it. And thanks all for the other suggestions - everyone was close. But, who could've guessed it exactly. . .

Rodney


----------



## CamperAndy (Aug 26, 2004)

Well right after a loose bolt I was thinking about a dead rat but I never would have connected the problem to the Love Bug!!!!

Grew up in FL and they were bad there. Living in ID now and I complain about having to clean a dozen bugs off the Outback after a 1000 mile trip. Now I am thankful I no longer have to haul in the Love Bug Zone as the front of the Outback would need a spatula to remove them.


----------



## tdvffjohn (Mar 10, 2005)

If one of us had suggested bugs nesting in the AC unit, we all would have had a good laugh







but there it was. Sometimes its just not as simple as a loose bolt









John


----------



## HootBob (Apr 26, 2004)

Glad to hear you found what the problem was
Never would of thought of bugs

Don


----------



## RAAAT (Jun 26, 2004)

Yeah, it's weird.

The fault lies first and foremost in the love bugs - second, in the condenser fan design. As I mentioned, it looks much like a spoked wheel. The fan blades emanate from the central hub and terminate in an outer rim - unlike many styles of fan where there is no outer rim. Apparently, the fan spun with the blades prematurely ending the little bugs' bliss and hurling their tiny squished bodies into the outer rim. The centrifugal force of the spinning fan assembly held their now-crushed exoskeletons to the outer rim while their body fluids oozed out in a sort of morbid glue. This cycle repeated itself tens of thousands of times until the accumulated carnage added additional weight to the outer rim of the fan.

The final mystery lies in why only about 1/3 of the fan exhibited bug body build-up. The way I see it there are two possibilities: either love bugs and Carrier V air conditioners adhere to the fruit and jello conundrum, or, originally, love bug build-up covered the entire circumference of the fan rim and about 2/3 of it simply feel off during the camper's months of storage.

As to the former possibility, consider the fact that fruit tends to seek its own, forming inevitable clumps in the jello mold. Cold reason, on the other hand, dictates a random distribution of fruit in deference to the preparer's thoughtful stirring. Perhaps this unexplained phenomenon infiltrated the love bug/Carrier V universe. If that's so, there's no telling where it will strike next.

Let's hope the latter possibility occurred - that love bug guts just don't make an effective adhesive. Otherwise, we could all be in trouble.









Rodney


----------

