Mach 8 hush kit ?

[voltdoc]

Stopped near Lewisville, TX last week for an appointment with Orbital Machine Works to take a look at our 15K BTU reverse cycle Coleman MACH 8 roof AC units to ensure their compatibility with their "Hush Kits" - and they have assured me that they are.

I have two of the kits installed so far and IMO the noise reduction outside is significant - even when the AC units are in "high" mode. If you care about the noise your AC units make outside, this kit is something to consider.

These are the kits I am talking about: Mach 8 hush kits Most late model Entegra/Tiffin, etc. that use the Coleman MACH 8 will already have the three blade "D" fan so the partial kit is all you need. If you don't yet have 3 blade fans with a "D" in the part number (embossed on the top of the fan hub) they WILL fail, but Coleman should provide replacements at no charge, at least if you are still under warranty.

The majority of the noise reduction by this kit is achieved with the motor speed controller. It reduces the condenser fan speed on BOTH "High" and "Low" (or "Auto") thermostat settings.

It was explained to me that the three blade fan now standard on all the Mach 8 units moves significantly more air than the original 6 blade fan that sounded like a jet engine. The hush kits basically slows the fan down and reduces the airflow to the original design requirement, thereby making things a LOT quieter. On "High", the kit reduces the fan speed so it provides slightly more flow than the original 6 blade "A" fan. On Low, the fan speed is reduced just a bit more.

The new metal grill reduces the air flow noises even further but by a more subtle amount.

We [unscientifically] tested our #2 and #3 AC's that have the kit, against #1 AC unit that does not yet have it. The noise difference at ground level is very notable to our ears, and sometimes it was even hard to tell if the units with the kits were running at all. On the roof, the fan noise no longer overwhelms the normal AC compressor noises. We have not experienced any reduction in cooling.

[Matt D]

Rob, super update. Any suggestion on how much time it takes to install one of these kits?

I remember our shroud as being black, is that correct?

Thanks,

-Matt

[lowejug]

Yes .. I also thank you for your update... I am considering this hush kit and now summer around the corner I need to decide.
Your info helps dramatically... so no loss of cooling because of the kits?

Thanks again

[voltdoc]

Originally Posted by Matt D

Rob, super update. Any suggestion on how much time it takes to install one of these kits?

I remember our shroud as being black, is that correct?

Thanks,

-Matt

Matt, probably less than 10 minutes for the motor controller and another 10 for the grill. Not counting setting up the ladder and trips up and down to get the right tools (wire cutter, crimper, pliers, screwdrivers, nutdrivers, box cutter and a drill for the grill mounting holes).

There are 4 wires to hook up. Removing the three blade fan (one screw) gives you more room to work on the wire splices. You cut one wire to the motor and splice the two red wires from the controller box to the two ends of the cut wire (first photo). You tap into the existing AC control unit black and white wires with the black and white wire from the controller box (second photo) - don't confuse the black/white AC unit controller wires with the black/white wires for the condensate pump motor. Mount the control box to the side of the inner fiberglass shroud with self drilling screws and/or VHB tape. That's it. I used adhesive lined shrink crimps for the splice (instead of the supplied wire nuts) and also painted the wire taps with liquid electric tape just for added corrosion protection.

The grill in the shroud cuts out easily with a box cutter. Then just center the new metal grill, mark one of the mounting holes and fasten with supplied bolt, then using the mounting holes as a guide, drill the remaining mounting holes and attach with bolts and nylock nuts (don't overtighten).

Yes the shroud is black, the grill can be ordered in black or white. Sorry, forgot to take a picture of the grill.

Photo below shows the black condenser fan motor wire cut and the two red wires from the control box spliced in with adhesive lined shrink crimps (bluish crimp insulation):


Photo below shows the control box and taps (blue) for the motor control power. I later sealed the taps with liquid electric tape. Don't confuse the proper black/white wires with the black/white wires connected to the condensate pump. The large cylindrical motor shown in this photo is the blower motor, the small motor to the right is the condensate pump. The partially detached foam strip shown in the photo was re-glued in place.

[voltdoc]

Originally Posted by lowejug

Yes .. I also thank you for your update... I am considering this hush kit and now summer around the corner I need to decide.
Your info helps dramatically... so no loss of cooling because of the kits?

Thanks again

So far we have not noticed any difference in cooling. The folks at orbital Machine Works are quite confident that their kit will not lessen the cooling power since the condenser fan air flow is actually still a little bit higher than the original Coleman design with the six blade fan. Will report back if we find any problems down the road, but so far VERY happy with this mod.

[wmpbauer]

Does anyone know if Coleman will supply the hush kit components free of charge under warranty, or only as an upgrade for a fee?

[brobox]

Pat see post #8, http://www.irv2.com/forums/f278/mach...ml#post3444184
Coleman won't even acknowledge they exist

[voltdoc]

Originally Posted by brobox

Pat see post #8, http://www.irv2.com/forums/f278/mach...ml#post3444184
Coleman won't even acknowledge they exist

Yes the hush kit is 100% designed and developed by Orbital Machine Works to correct shortcomings in the Coleman product. Guess you could say it's a sad state of affairs when the OEM can't be bothered to properly engineer their product in the first place. On the other hand, aftermarket add on's to improve a product are pretty common and this is one of those that for some of us are well worth the cost. Others may think the noise level is perfectly acceptable as it is.

I am in the group that wants the A/C units as quiet as possible and $325 is a lot cheaper than ripping out all the Coleman product and replacing with ?? and dealing with the ripple effect of all the other subsystems that will be affected.

[Tall Tex]

This all sounds great for noise reduction, however I would need to see real air flow data through the condenser compairing the original A fans to the new 3 blade fan slowed down. Insufficient air flow through the condenser causes higher pressure on the high side of the system, which will shorten the life of the compressor. This type of system can not have too much condenser capacity. This is especially true when the ambient temperatures climb above 90 degrees. When near 100 degrees like we have in the south most of the summer we need all the AC capacity we can get.

If you install these kits and experience the AC units cutting off around 4:00 pm when the heat load reaches it's peak, it could be you've tripped the high pressure cut off switch.

Let us know how the hush kit units cools when it's pushing 100 degrees outside.

Good luck.

[brobox]

Originally Posted by wmpbauer

Does anyone know if Coleman will supply the hush kit components free of charge under warranty, or only as an upgrade for a fee?

Coleman wouldn't even replace the loud six blade fans under warranty, we had to upgrade those out of pocket. I remember Mike at Coleman CS saying the were not needed. After I purchased them.....how wrong he was, they cut the noise on my units by 50%

[lowejug]

Originally Posted by Tall Tex

This all sounds great for noise reduction, however I would need to see real air flow data through the condenser compairing the original A fans to the new 3 blade fan slowed down. Insufficient air flow through the condenser causes higher pressure on the high side of the system, which will shorten the life of the compressor. This type of system can not have too much condenser capacity. This is especially true when the ambient temperatures climb above 90 degrees. When near 100 degrees like we have in the south most of the summer we need all the AC capacity we can get.

If you install these kits and experience the AC units cutting off around 4:00 pm when the heat load reaches it's peak, it could be you've tripped the high pressure cut off switch.

Let us know how the hush kit units cools when it's pushing 100 degrees outside.

Good luck.

hmm.. so in the west around the nevada/arizona desert where its not uncommon
to reach 110 degree daily for a couple months this kit might be a problem.
thanks for your input... I will once again re-think this

[Matt D]

Regarding the cooling efficiency, the company that developed this is near Dallas, and these kits have been in use for a few years now.

I was unable to locate any derogatory comments about this kit when I looked last night.

This kit was developed for the small Casita trailers, then quickly spread to many others. People with Motorhomes quickly took note, and this is a very popular mod with Tiffin owners.

Statistically, there must be an unhappy customer out there, I just couldn't find them.

I'll be picking my set up on Monday just before dropping the coach at NIRVC.

-Matt

[Jose67]

Originally Posted by Tall Tex

This all sounds great for noise reduction, however I would need to see real air flow data through the condenser compairing the original A fans to the new 3 blade fan slowed down. Insufficient air flow through the condenser causes higher pressure on the high side of the system, which will shorten the life of the compressor. This type of system can not have too much condenser capacity. This is especially true when the ambient temperatures climb above 90 degrees. When near 100 degrees like we have in the south most of the summer we need all the AC capacity we can get.

If you install these kits and experience the AC units cutting off around 4:00 pm when the heat load reaches it's peak, it could be you've tripped the high pressure cut off switch.

Let us know how the hush kit units cools when it's pushing 100 degrees outside.

Good luck.

Hello Larry,

I installed mine in July, '16. Used them in central Florida since. No breakers tripping on any unit. In fact, the units operate at 16 amps while cooling and 15 amps heating. No complaints here.

[Tall Tex]

Originally Posted by Jose67

Hello Larry,

I installed mine in July, '16. Used them in central Florida since. No breakers tripping on any unit. In fact, the units operate at 16 amps while cooling and 15 amps heating. No complaints here.

I'm glad it works good for y'all. I spent my working life conducting automotive testing projects which included over 20 million miles of AC compressor testing for GM prior to the introduction of 134a refrigerant. As a result I'm always skeptical when modifications are made without OEM support and engineering. There are a lot of products out there that are not what they claim to be. With our expensive toys it pays to be a bit skeptical. Just sayin!