Thursday, June 1, 2017

Mods to Make the Air Conditioner Quieter

The Airexcel Mach 10 air conditioner in the Fuse is noisy.   It is mostly noisy since our motorhome is small and there is no way to escape being right next to it.    It would be nice to make the air conditioner quieter.

Coleman  Mach 10 Air Conditioner

For a while I have tried to understand what all the noise was from.  Was it from the air conditioner compressor?   Was it from the fan?   Was it from the air rushing around?

I spent a little time looking into all of these.   And it seemed most of the noise was just from the air rushing out.

I did talk to Airexcel (Coleman) to see what hints they could give.    In some older air conditioners there was lots of noise coming from the compressor or from the compressor fan.   I was told with these units they were as noisy outside as inside.   Our Fuses do not have that problem since they are newer than these problems.   They sold a hush kit with a different fan for these.

In some cases, over tightening the air conditioner screws to the RV would cause excessive noise.  The vibrations from the A/C would travel throughout,  creating noise.    Not a problem I was having, but a good tip.

The A/C air handling fan could be another source.  I took the cover off and it seemed quiet enough.  No noise coming from a noisy fan.   It seemed as if most of the noise was coming from just the air rushing out and moving through the duct and air vents.

At least the problem is identified.  Air moving makes noise and we have lots of it.  The Mach 10 is moving air at the rate of 310 cubic feet per minute.  Not a small amount.

In the Facebook group (Winnebago Fuse Owners) we have been discussing this for a while.  The key to any air conditioning mod is to not restrict the airflow.  This will cause the air conditioner to freeze up.  I tried each independently.

Two Mods were discussed that appeared promising.

Mod 1 - Sharon Berg in the Facebook Group suggested using a Duck Brand 1286294 Air Conditioner Foam Insulating Panel and place it in the bottom of the register. This foam panel has ripples cut into it.   This is placed on top of the foam that is already in the register.   You have to do some trimming to cut out voids for the controls and the bottom air outlets if you have a Deluxe ChillGrille.

Foam Insulating Panel

This was pretty easy to do and inexpensive (less than $10.00).   I measured a sound difference of .5db at the head of the passenger bed and at the front of the love seat.

Mod 2 - Kevin Under posted a second option and wrote it up in the Facebook.  Find the file here.  The method is to use 1/8 " foam pipe insulation tape and line the inside with the tape.   I did this and saw a decrease of 2db.  From 70 to 68 decibels measured at the head of the bed.  At a subjective level, I can now watch TV at level 68 down from level 75.   (It was at level 95 before I replaced the register with the ChillGrille Deluxe.)

Foam pipe insulation 1/8" x 2"

Foam pipe insulation method in ductfoam pipe insulation in register

I believe that the majority of the help came from the tape in the duct than from the fan to the register. I have no measurements (I forgot), but I had tried a piece of thicker foam earlier in the duct directly below the fan and saw a 1 db drop using the phone app.

Foam in A/C duct

No comments:

Post a Comment