Reducing generator and air conditioner noise

[komac]

We traded in our class A motorhome and bought a new B class Dodge Trend. I'm happy with it, but I'd like to make both the generator and air conditioner less noisy. On my class A, I could hardly hear either of these when they were running. The trend's generator is louder than a lawnmower, and the air conditioner is almost as loud. I'd appreciate any suggestions. komac

[BFlinn181]

Very likely like a lawnmower, your generator is air cooled. Be careful about stuffing insulation or blocking air flow to it. On the A/C, it also may be a result of the way air comes out. On many RVs, the air is ducted and comes out multiple vents. Is yours like that or just blowing out from the bottom of the A/C unit itself?

[komac]

The Trend's AC is not ducted. It blows directly into the unit through vents on two sides. I can get used to the noise inside the unit, but the outside noise at the roof is quite loud. I won't be a good camp ground neighbor, especially on a hot night, although, I'm sure most other campers will also be operating their ACs. As far as the generator is concerned, I'm going to cut the exhaust pipe somewhere in the middle and add a small baffled muffler. Mostly we use the generator when we pull into a rest stop and have lunch. Any other noise reduction suggestions are very welcome! Ken

[BFlinn181]

Isn't there already a muffler on the exhaust of the generator? Adding another might allow back pressure and heat build up. I'd listen carefully, the noise could be from the air cooled nature of the engine instead of a water jacketed cooled system of a bigger generator.

[Alan Wilson]

Originally Posted by BFlinn181

Isn't there already a muffler on the exhaust of the generator? Adding another might allow back pressure and heat build up. I'd listen carefully, the noise could be from the air cooled nature of the engine instead of a water jacketed cooled system of a bigger generator.

I totally agree. What I would prefer and what I had considered when I had my Class B was to get the exhaust to exit above the side of the camper. If there is too much back pressure you will have the pleasure of putting in a new, quieter generator when your current one gets ruined. For a couple hundred dollars or so an extended exhaust can be added that should reduce the generator noise and reduce the risk of carbon monoxide getting into the living quarters.

My two cents.


Alan Wilson

2001 HR Scepter 38 PBD

[raineman]

Here is something I bought to quiet my generator and keep the fumes above the roof line. It is called the Genturi. It makes my generator much quieter. I also bought the suction cups instead of drilling holes in my rig and the pipe extension.

http://www.amazon.com/gp/product/B00...ilpage_o02_s02

[Alan Wilson]

Originally Posted by raineman

Here is something I bought to quiet my generator and keep the fumes above the roof line. It is called the Genturi. It makes my generator much quieter. I also bought the suction cups instead of drilling holes in my rig and the pipe extension.

http://www.amazon.com/gp/product/B00...ilpage_o02_s02

That is the thing I was talking about! I could not remember the name! Thanks,


Alan Wilson

2001 HR Scepter 38 PBD

[Showkey]

Only way to quiet those Onan generators .................buy a portable Honda or Yamaha.

[Hit_the_Rhod]

You can make a reasonable home built "up pipe" for your generator with parts from Lowes or Home Depot. Just don't fasten it tightly to the existing exhaust. Unfortunately, like other posters have mentioned I think you'll find that most of the noise is a result of your new genny being air cooled, and just less mass than you are used to in your water cooled, well insulated generator in the class A.

[komac]

Thanks everyone for all the suggestions. I checked with our Cummins-Onan dealer and was told that I would void the warranty if I made any modifications to the exhaust system. The dealer confirmed that the noise comes from its air-cooled design, which is inherently more noisy than a water cooled system. We rarely use the generator in camp grounds. We use it when we are parked in interstate rest areas or in shopping mall parking lots. Komac

[BFlinn181]

The Gen-Turi Generator Exhaust just extends the exhaust to exit above the roof. It doesn't restrict the exhaust at all, the fast moving exhaust passes into the plastic chimney drawing more air in with the venturi effect at the opening, cooling the gases and allowing it to rise to the rooftop exit. I don't think it would void your Onan warranty. Cutting the exhaust pipe and adding an extra muffler certainly would.

[komac]

I finally got under the rear end of the Trend yesterday to see whether the exhaust pipe was touching the frame and thus causing the noise I was complaining about when the generator is running. I put the rear wheels up about two inches on leveling blocks and that gave me a fair amount of room to examine the whole area. The Onan generator on the trend is located under the coach in the middle of the chassis, just behind the rear wheels. The exhaust pipe exits the left side of the generator (as you are looking toward the front of the coach) and extends out to the side of the coach. I bumped the exhaust pipe with my hand several times and heard a bumping sound, even though the exhaust was several inches from the frame. I looked at the pipe as it exits the pan which the generator sits on and found that the pipe was within a sixteenth of the side of the exit hole. That's where the noise was coming from. There are four bolts which anchor the generator to the pan which the generator sits on. Those bolts go through holes which are elongated, thereby giving adjustment room. All four bolts were at the extreme end of each elongated hole. I loosened each bolt and pulled the generator to the rear nearly a quarter of an inch, then tightened them. This adjustment gave the exhaust pipe plenty of room around the exit hole, and there was no more noise when I bumped the pipe with my hand. I started the generator and the former noise had disappeared! The Onan 2800 generator is not as quiet as my former larger generators on my class A motorhomes, but it is now what I call "civilized." It was an easy fix. komac

[BFlinn181]

Thanks, komac, for reporting on your solution.