air cond unit vibration

[GlenB]

My rear Air Cond unit on 2005 fleetwood expedition 38N Diesel seems to have some vibraition that sets up as the units Compressor comes on. It cools OK but that vibration seems to get a little louder has it works. Not real bad but enough at night to bother you a bit. I wondered if the rubber mounts that are on the units can wear to the point more of the vibration is then sent into the roof itself. The unit was lived in over several summers before I bought it so they have seen some running down in Fla.....heat. tks for help...glen

[C-PHartley]

I just replaced my front air gasket - $25.00 for the gasket and about an hour of labor. A fairly simple job, but the unit weighs 75-100 lbs, so it helps to have someone to hold it up while you replace the gasket. It could also be that the bolts that hold the unit down just need to be tightened. This did seem to dampen some of the noise.

[Rex]

You may not need a new gasket. If the current one is not fully compressed, then you may only need to tighten the four bolts inside the coach that hold the roof unit in place. They should be tightened to 40 inch pounds. That is INCH POUNDS, not foot pounds. That should take care of the vibration if the bolts are a bit loose.

Also take the cover off the roof unit and check the motor squirrel cage for dirt dubbers. That will make it out of balance and cause vibration.

[tvman44]

Also pull the cover and look for dirt dauber nest on the fan blades.

[GlenB]

I meant to mention that these units have the heat pump type system. I am wondering if that causes a little more vibration.....I plan to check the things that are mentioned here and tks for the help...glen

[RV Wizard]

Check the plate the compressor is mounted on if it is a Dometic, Duo-Therm, low profile that has a horizontal mounted compressor. I just had to add a rubber bulb seal to cushion the plate as the original rubber wore out. I also had to replace the plastic blower wheel as it had warped out of shape and bouned up in the housing.

[puttin]

Guys,

If theses suggestions don't work- there may be another possibility. I have Colemans on mine and a few years back, I had an annoying vibration as well. I went up there, took off the shroud and with the unit running- I noticed a copper line was running too close to the pan and was vibrating against it. I just pulled it away about a quarter inch so the shroud would just clear it and all has been good since...

[LadyFitz...]

Quote:

Originally Posted by GlenB I meant to mention that these units have the heat pump type system. I am wondering if that causes a little more vibration.....I plan to check the things that are mentioned here and tks for the help...glen

The only significant mechanical difference between an A/C and a heat pump is the reversing valve. The only way that valve could cause vibration would be if it was rapidly cutting in and out and you would notice a severe reduction in heated or cooled air output.