A/C Vibration (Rear)

[Fergtiffin]

Working bugs out of new to me 2018 Cornerstone (Under warranty). The rear AC is significantly noisier that my allegro bus or the other coach air conditioners. Vibration transmitting through rear of coach. Significant at entrance to rear bath. Is this "normal" - just does not seem right. The tech here at NIRVC Phoenix has worked on the insulation (not sure exactly what he has done as I could visually inspect) He is obviously knowledgeable engaged. Could my expectation be off and it is just the way the way the unit is mounted to the roof structure??

[Gasman 2]

There have been some issues on earlier ACs when a blade has broken off the fan on the compressor. Did they check that?

[Fergtiffin]

I know he had the shroud off and put new foam in so I am sure he visually inspected fan. I am impressed with tech (Radley at NIRVC Phoenix) May have to compare with another Cornerstone to see if this is normal. My bride says it is not

[brobox]

On my 14 the fan mounting bolts were loose with one the A/C missing 2 bolts, that was the noise one. Other have reported damaged squirrel cage fans have caused vibration. Being new, it might be out of balance, bad castings do happen

Here is one post as an example. http://www.irv2.com/forums/f278/anot...ml#post3328386

[Fergtiffin]

The out of balance condition fits my instincts. Thanks! Will follow up on tip

[brobox]

Originally Posted by Fergtiffin

The out of balance condition fits my instincts. Thanks! Will follow up on tip

I had a plastic molded product for 18 years. Not unusual to have a bad one get through the line. If the mold cooled to much between cycle, unbalanced molded finished product. It may look good but the plastic did flow 100%

[Rollin101]

To ck if it’s the squirrel cage fan just turn on fan. Squirrel cage is the only thing that will run. My guess is that it is the squirrel cage fan if there’s a vibration.