Coleman A/C fan upgrade - 6 blade to 3 blade

[Jupiter]

2013 36M with Coleman A/C's

As many of you know the late model Coleman rooftop A/C units are terribly noisy on the outside. They sound like mini turbines with the high speed 6 blade condenser fan. So, as some of you have suggested I contacted Coleman and bought two new 3 blade replacement fans for this particular model Coleman.

Good news - the noise level outside has reduced to a tolerable level.

The BAD news - The noise inside has dramatically increased from what I would describe as a harmonic vibration that is ridiculously unacceptable. Has anyone else upgraded to the 3 blade fan and experienced a similar increase with interior noise level? I'm thoroughly disgusted with Winnebago for using this annoying loud model to begin with, and now even more disgusted that the new fan blades seems to have amplified the noise level on the inside.

I'm thinking that the new blades may not be properly balanced. The 6 blade fans had a small balance weight on one of the blade and the new fan has no balance weight on any blade. The noise inside is not a steady hum or vibration. It's more like a harmonic sound like a rum..rum..rum..rum.. etc.

At this point I'm ready to seek total rooftop replacements with a brand that actually functions with a NORMAL noise level. And did I mention that two rooftops on the 36M are marginal at best in terms of cooling capacity in hot weather.

Yup... been on the road a few days now with the new fans and today I am not a very happy Winnebago camper

Joopy

[j.smith]

I just replaced a three bladed fan today as it started to self destruct, one of the blades cracked from the edge to the hub, sounded like a helo crash landing on the roof. I was able to purchase a replacement from 6 Robbles here in Anchorage, forget getting help from Winnebago. I have one unit with a three blade and one with a six, if I could find another six bladed fan that is what I would go with on both units.

[oopypic]

Greetings. I just finished replacing the 6 blade with the 3 blade D version fans, and I noticed the harmonic beat. Its about 1 or 2 hz. It only is heard at certain points inside the coach. I am going to adjust the hold down bolts to see if that makes a difference. Mine have springs on them. I also put sound absorbing material around the inside fan plenum and against the cover. My coach is now quieter inside.
Jim 15 Forza 34T TX

[grtharris]

Jupiter Yes I put the new fan blades on and took them off because of the hum inside the coach. I'm thinking about trying them again. I had to remove the rear AC unit to install a power delay (long story) and found the hold down screw springs completely compressed, only supposed to be 80% compressed. So I'm going to see if that makes a difference.
Here is a thread with lots of good info about the fan blades.

http://www.irv2.com/forums/f278/rvp-...it-210236.html

[Old Crows]

Joopy, same problem with noise. I Macgyvered a satisfactory solution. Quiet inside and out. First, you need more than the revised fan. The kit should include a U shaped support for the "bendy" plastic cover. The cover bends down and rubs against the pipe off the compressor. The support keeps it from vibrating against the compressor.....

The cover/bonnet is a thin plastic and has no strengthing ribs molded into it. Essentially it is a drum head that sympathetically resonates with the vibration of the fan and the compressor.

The plastic cover for the evaporator is heavier but is also a resonating surface that picks up noise and vibration from the internal squirrel cage and from all the other racket going on under the bonnet.

What to do? First, check,that the rubber isolator so on the fan motor and compressor are good. Install the fan and make ABSOLUTELY sure there is at least 1/4-5/8" clearance between the tips and the metal electrical box. Tips hitting the box is the cause of fan failure. You cannot increase the height of the fan by adding a spacer.

The problem with the bonnet is solved by adding "mass damping" material to the underside. I used butyl aluminum faced roofing tape applied to the underside of the bonnet. Aside from stiffening and adding mass it also insulates.

The box over the expansion coil and internal fan was covered with aluminum foil HVAC tape. Space is limited here and it was the easy solution...and it reflects heat and solar radiation.

The unit is now so quiet you can barely hear it running when standing outside near the rear wheels of my View. Inside almost all of the mechanical noise and drumming is gone and you hear only duct noise.

I'll post my write up and photos here tomorrow...

[Hagenl]

I had the 3 blade replacement from Air Excel at GNR in 2014. It had a "B" in the model number and one blew up last weekend. I got 2 "D" model fans at no charge and installed them. The front was just fine but the rear was too close to the metal cover over the wiring. I removed the nut under the rear side of that cover and fastened it back down so no problem on the metal box cover. However the fan rubbed against the top plastic cover at startup and shut down so I shimmed up the lower right corner of the roof cover and solved that too. Not a whole lot of tolerance around these blades and I hope the "D" models actually hold up. We leave the air on lots of times when away from the coach and a fan blow up could lead to any number of nightmares. Air Excel (RVP) replaced them without any questions except serial # of the air conditioner units.

[Jupiter]

Thank you all very much for the informative responses! I now have a few ideas to try to make our coach livable again. I contacted Winnebago but I'm not holding my breath for a solution from them. So disappointing that they would specify such a poorly engineered component. I still think the 3 blade is not balanced which creates much of the vibration. Beyond the vibration issue, one concern is that eventually the out of balance condition can wipe out the condenser fan motor bearings.

OLD CROWS - looking forward to your write up and photos. Looks like you made a big impact on the noise level. Thanks for sharing.

Oh, and I still have the 6 blade fans if all else fails, but then I'm back to square one.

cheers,
Joopy

[Old Crows]

Sorry for the delay Folks.... I realized I had to update my work. The link below should take you to a description of how I MacGyvered my unit.

Joopy, Athough I have a prop balancer for my RC planes, I did not attempt 'balance' the new fan. It has a balance weight on it and it is probably 'good enough.' I did carefully scrape and sand off all the 'flash' and molding marks on the edges of the blades so that they are smooth and clean. It's a really cheap moulding and needs work!!!! The idea here was to get the smoothest air penetration and departure over the blade. Those small imperfections create vortices and all kinds of mayhem leading to increased noise..... probably lost inside the unit... but nevertheless!

I'm generally not inclined to complain about stuff but become more motivated when ignored; told I don't know what I'm talking about; or suffer disparate treatment ..... Clearly, Coleman has a long standing issue with extreme noise from these units (15K heat pump) as evidenced by the many threads and complaints on the internet. As we know, there is a 'fix' ... but only available to who stumble upon it and who complain. Still, the Coleman solution is uneven and disparate ... not everyone benefits from the 'secret' improvement.

When you're shopping a new $100K+ .... hell, even a less expensive model.... one expects that the manufacturer's have done their due diligence and scoped out such a sensitive issue as 'noise abatement' in their product. Folks like QUIET in the RV park and elsewhere. While Coleman is directly responsible for the miserably loud performance of their unit, I also hold Winnebago responsible for continuing to install these beasts on their otherwise nice units. Winnebago could put the muscle on and help their customers (and those who are within earshot of these crappy units). Winnebago and other manufacturers need to lean heavily on Coleman to retrofit every unit ever installed at Coleman's expense. The alternative is to never have another Coleman product on the production line.... That should fix it....

Here's the linky: https://drive.google.com/file/d/0BzX...ew?usp=sharing

[Triker56]

Hummmm!! I just went outside and my 15K Coleman front Heat pump(New 9/17/13) and the rear 13.5k AC(New 6/28/12) sounds the same. But are both quieter then my neighbors newer looking Dometic AC's.

Inside I hear no noise from the roof fans. But maybe my roof has better insulation that blocks out any noise inside.

There is the regular inside fan noise. But no louder or quieter then any other AC I have had in any RV the last 40 years.

[Jupiter]

Originally Posted by Old Crows

Sorry for the delay Folks.... I realized I had to update my work. The link below should take you to a description of how I MacGyvered my unit.

Joopy, Athough I have a prop balancer for my RC planes, I did not attempt 'balance' the new fan. It has a balance weight on it and it is probably 'good enough.' I did carefully scrape and sand off all the 'flash' and molding marks on the edges of the blades so that they are smooth and clean. It's a really cheap moulding and needs work!!!! The idea here was to get the smoothest air penetration and departure over the blade. Those small imperfections create vortices and all kinds of mayhem leading to increased noise..... probably lost inside the unit... but nevertheless!

I'm generally not inclined to complain about stuff but become more motivated when ignored; told I don't know what I'm talking about; or suffer disparate treatment ..... Clearly, Coleman has a long standing issue with extreme noise from these units (15K heat pump) as evidenced by the many threads and complaints on the internet. As we know, there is a 'fix' ... but only available to who stumble upon it and who complain. Still, the Coleman solution is uneven and disparate ... not everyone benefits from the 'secret' improvement.

When you're shopping a new $100K+ .... hell, even a less expensive model.... one expects that the manufacturer's have done their due diligence and scoped out such a sensitive issue as 'noise abatement' in their product. Folks like QUIET in the RV park and elsewhere. While Coleman is directly responsible for the miserably loud performance of their unit, I also hold Winnebago responsible for continuing to install these beasts on their otherwise nice units. Winnebago could put the muscle on and help their customers (and those who are within earshot of these crappy units). Winnebago and other manufacturers need to lean heavily on Coleman to retrofit every unit ever installed at Coleman's expense. The alternative is to never have another Coleman product on the production line.... That should fix it....

Here's the linky: https://drive.google.com/file/d/0BzX...ew?usp=sharing

Wow... thank you OLD CROW for sharing your write up. You've really put forth significant effort in to both the "fix" and the article.

I'm on the road at the moment but intend to carefully read every word in detail when I return home next week. I couldn't agree more that both Coleman and Winnebago should be ashamed to have this product on motorhomes today. And I ultimately hold Winnebago responsible because they chose they specified this unit and therefore should be responsible to do the right thing and either recall this product or at the least offer a reasonable "fix" for their customers. I've contacted Winnebago via their website several days ago asking for a solution but have yet to hear back from them.

Interesting how the auto industry can offer millions of service bulletins (not to be confused with recalls for safety items) for faulty auto components but the RV industry seems to be exempt from such a customer satisfier. I guess they do it... because they can.

Thanks again, Old Crow for your effort and willingness to share!

Joopy

[Old Crows]

Originally Posted by Jupiter

Wow... thank you OLD CROW for sharing your write up. You've really put forth significant effort in to both the "fix" and the article.

I'm on the road at the moment but intend to carefully read every word in detail when I return home next week. I couldn't agree more that both Coleman and Winnebago should be ashamed to have this product on motorhomes today. And I ultimately hold Winnebago responsible because they chose they specified this unit and therefore should be responsible to do the right thing and either recall this product or at the least offer a reasonable "fix" for their customers. I've contacted Winnebago via their website several days ago asking for a solution but have yet to hear back from them.

Interesting how the auto industry can offer millions of service bulletins (not to be confused with recalls for safety items) for faulty auto components but the RV industry seems to be exempt from such a customer satisfier. I guess they do it... because they can.

Thanks again, Old Crow for your effort and willingness to share!

Joopy

Thanks for the flowers!

Maybe Winnebego is my next project. Over all we love the View Profile and there are very, very few issues. Three to be exact... the noisy HP; a failed LP regulator in 14 months (there is a story here about mine and my View's sister owned by my neighbor); and, some screwed up gaskets & cross threaded fittings in the H & C water lines at the shower valve behind the shower wall.

They are not keen on answering calls or emails.

Yes, I think RV manufacturer's have not joined the 21st Century regarding customer satisfaction/follow up/attending to details/not proactive. Maybe I'm spoiled by customer service at my Toyota and Mercedes Store .... NOT! "You want Starbucks with that croissant?" "Your Camry had a smudge on the hood.... we' washed it for you....."

Unless you purchased a $500K + rig, you don't have their attention. RV companies remind one of the General Motors of the '60s thru 90s. "It got you off the showroom floor didn't it?? Quit yer bitchin'!!!!!"

PM me if directions are not clear.

Peace,

The Crow

[ernieh]

There have been clearance issues between the AC base pan and the roof. This can be caused by improperly torqued hold down bolts, but some have added spacers ( think rubber door stop wedges) between the roof and base pan.

Those who have done this claim that it makes a big difference.


Although my AC's don't use the same fan, I have installed several for other folks and have found at least 3 or 4 broken fan motor mounts in the process.


It's absolutely amazing to me how a manufacturer with years of experience can suddenly produce a unit with so many issues.

[loisjop]

You might want to look at the ENTEGRA site. We started replacing these fans a yr. ago. Make sure you have what they call a hat that sits on top of the electric box and holds the a/c shroud off the condenser fan. Also if you have any three blade fan that's not the D model you are subject to having a fan failure. The older B&C model fans start getting egg shaped and cracks start appearing in the hub at the blade root, usually after about three months of operation. The new D fans became available in March so if you have anything older that about April 1st it's not a D model fan. I have had prototype D models for about five months and haven't had any problems with them. I had several failures with the B&C models.
You can find the p/n xxxxDxxxx stamped into the top of the blades. I would advise anyone with any three blade fan other than a D to replace it and make sure you have the metal "hat" on top of the electric box. When installing the fans make sure the blade tips clear the electric box. All you need is approx 3/16 in and you can add a spacer under the fan if needed to achieve the clearance. I used nylon washers on mine.

[Jupiter]

Thanks for the response, Noel. Yes, a previous poster provided a link to the Entegra thread which was very informative. I'm soaking it all in so I can try to resolve or at least improve the condition to the point of a reasonable noise level.

I sincerely appreciate all the great responses! And, I'm betting others appreciate the informative postings, too.

cheers,
Joopy

[Old Crows]

Originally Posted by loisjop

You might want to look at the ENTEGRA site. We started replacing these fans a yr. ago. Make sure you have what they call a hat that sits on top of the electric box and holds the a/c shroud off the condenser fan. Also if you have any three blade fan that's not the D model you are subject to having a fan failure. The older B&C model fans start getting egg shaped and cracks start appearing in the hub at the blade root, usually after about three months of operation. The new D fans became available in March so if you have anything older that about April 1st it's not a D model fan. I have had prototype D models for about five months and haven't had any problems with them. I had several failures with the B&C models.
You can find the p/n xxxxDxxxx stamped into the top of the blades. I would advise anyone with any three blade fan other than a D to replace it and make sure you have the metal "hat" on top of the electric box. When installing the fans make sure the blade tips clear the electric box. All you need is approx 3/16 in and you can add a spacer under the fan if needed to achieve the clearance. I used nylon washers on mine.

Sound advice. Thanks.

After surfing the Entegra thread, its clear there are significant issues with early fan blades. I'm NOT buying into the theory that the failures are due to 'dry nylon.' I've been flying electric RC airplanes for 10 years. They all use nylon props.... and gas/glow motors are moving to carbon fiber types. Nylon props are nearly indestructible and survive 10K+ RPM and prop strikes. in short you can auger in a very expensive plane and destroy it, the motor, the battery and the prop is perfectly fine. (Wouldn't recommend re-using it but you probably could....)

From the photos we see fatigue cracking at the trailing edge of the blade and 'belling' in the hub. Most likely this is due to vibration and lack of strength in the hub. Either the wrong material is being used or there is an inherent design problem with the hub ... or both. I'll SWAG, and say that the root cause is not enough material in the hub and that it lacks sufficient internal reinforcing webbing to keep the hub from pulling outward. Like the unit's flimsy shroud, its another issue of damping vibration by adding sufficient mass and webbing to the hub.

Since the 'upgrade' fan was taken from a different application to save $2 a fan, it is likely that the max motor rpm in the original application is considerably less than in the Mach 8 which relies on a high speed motor to save energy and get air flow. Consequently, the centrifugal forces on the hub exceed its design. Throw in a bit of twisting due to broken or too flexible mounts and the very real possibility of a blade strike on the electrical box and the problem magnifies.

One has to question the failure of the rubber mountings for the motor. Why? Those things should last the life of the unit.

I will also point out that on my Mach 8, put in service 18 months ago, the rubber weather boots/seals around the wire bundles are already seriously degraded. They are split, cracked and crumbling. Again, these bits should last the life of the unit and they are not.

It would seem that RVP would benefit from 'crowd sourcing' the solution to their problem......

[two-niner]

Old Crows: I agree with you 100%.

In real life, if you replaced the three blade propeller on a turboprop with a two blade propeller....How long before bad stuff happens.

I wouldn't want to be around when you hear "CLEAR"!!!

[Jupiter]

Say Old Crow... I noticed in the bonnet support in your tutorial pics, but the supports I just received look very different. I'll have to wait a few more days before I can check the rooftop units. Could be that we have slightly different Mach 8's ?

Oh, and they're plastic with a threaded insert on top but nothing to screw into it. Sorry, don't know why it posted out of rotation.

[grtharris]

Jupiter, yes that is different what does the picture in the instruction show?
Those are condenser coil brackets.

[Jupiter]

Originally Posted by grtharris

Jupiter, yes that is different what does the picture in the instruction show?
Those are condenser coil brackets.

Ahhh... Yes, that would make sense given their shape and the insert would be for one of the four bolts on the cover. RVP sent without instruction or drawings.

Guess I'll be on the phone once again tomorrow with RVP Coleman. Would you believe this company (or their tech support department) closes down for lunch?

Thanks for the help.
Joopy

[Old Crows]

Originally Posted by Jupiter

Say Old Crow... I noticed in the bonnet support in your tutorial pics, but the supports I just received look very different. I'll have to wait a few more days before I can check the rooftop units. Could be that we have slightly different Mach 8's ?

Oh, and they're plastic with a threaded insert on top but nothing to screw into it. Sorry, don't know why it posted out of rotation.

Ahhhhhh nooooooo! The support I received doesn't look ANYTHING like those!!

Mine looks like a metal strap. Bent like this: _||_. The feet glue to the top of the metal electric box with sticky tape. The top pushes against the bonnet and is unattached to the bonnet. It just rests on the support. No screws or bolts required.....

No idea what they sent you... They do look like the brackets used on the condenser... Would not swear to it. They look pretty flimsy.... If they are slightly taller than the OEM brackets, RVP may be trying to reduce the parts count and save $$$. OTH, and in Crow's opinion ( not that they asked ! ) that's not going to turn out well.

While raising the attachment points by lengthening the brackets wI'll only raise the rear of the bonnet. It will need two similar bushings at the front attaching screws. (Can't imagine how you would get those in place under the cover! ) The issue is that the bonnet is thin plastic stuff...very flexible.. heat, gravity, and I suspect fan suction pulls the dang thing down in the center causing it to rub on the compressor tubing. The metal strut I received pushes the center of the bonnet upward & off the mechanical bits.

Betting they sent the wrong parts.

I'm thinking RVP is like Monty Python, Benny Hill or the gang that couldn't shoot straight...