[360]

Ok, I need a pro tip.  I’d love for someone to show me what is the ultimate setup for removing vibration from my aux compressor.  I have so much vibration I can feel it laying in bed.  Not quite bad enough to wake me, but it’s close.

I have a board stuck to the bay floor, rubber dampers from board to compressor.  I’m running a little California Air unit that is not as quiet as a Thomas, but it’s a fraction of the price.

[Jack Houpe]

To be honest with you Harbor Freight sells a silent model for less than $200 that has very little vibration and is very quite. Ken and Pam bought one for a back up and I couldn't believe how quite it was.

[hbens]

To be honest with you Harbor Freight sells a silent model for less than $200 that has very little vibration and is very quite. Ken and Pam bought one for a back up and I couldn't believe how quite it was.

Here's the compressor I bought from HF. I hook it up in the engine bay for now if I need it. If/when my 115v compressor dies I'll figure out a way to cannibalize this pump and make it work instead of spending more on the direct replacement.

[Richard]

So………….

The idea is to prevent the low frequency vibration from the pump from transmitting to the frame of the coach. Let’s talk about the concepts. The pump is mounted to the floor of the gen blower bay, correct. The pump frequency is resonating in a harmonic with that bay floor.

You are going to have to experiment with different isolators to find what works with the weight of the pump, the vibration frequency, and the bay floor.

Keep these ideas in mind when playing around. The pump should be mounted on an isolation plate. The isolation plate should be mounted to the bay floor. Use isolators that with bolts that do not contact the pump, plate, or floor. You might think of something like this https://www.mcmaster.com/products/isolat...h-studs-6/ or like this https://www.mcmaster.com/products/isolat...ushings-6/

Now here is the key part. The plate material and thickness is really important. You may have to try different thickness steel plate to get the result you want. The idea is that the plate decouples the vibration of the pump. In different words. Some vibration will transmit from the pump to the plate, if the plate is the correct thickness and weight it will not vibrate at a harmonic frequency with the pump thus negating much of the vibration of the pump from transferring through the next isolators to the bay floor. I cannot tell you which isolator will work best, and I cannot tell you what the thickness of the plate should be. That is some specialized engineering. So you have to experiment.

Or buy a JunAir oil based compressor. You will faint at the price, but you will never know it’s on.

[HoosierDaddy]

I found a JUnAir a few years ago on ebay. A developer had bought a dentist office complex ( Junair is used in many dentist offices). He was selling all contents. It was priced "right"!

[Jack Houpe]

Hank that link doesn't open on my computer but I think I know which one your talking about.
I have 2 junairs the rocking piston (spare one) and the oil type both are 220v I bought them cheap on ebay as Richard said You have to touch the oil type unit to see if its running but the only downfall is you have to check the oil level every month mine uses oil every month. I did put a counter on the compressor I can set it to 0 come back the next day and know if my system is OK or not.

[360]

So………….

The idea is to prevent the low frequency vibration from the pump from transmitting to the frame of the coach. Let’s talk about the concepts. The pump is mounted to the floor of the gen blower bay, correct. The pump frequency is resonating in a harmonic with that bay floor.

You are going to have to experiment with different isolators to find what works with the weight of the pump, the vibration frequency, and the bay floor.

Keep these ideas in mind when playing around. The pump should be mounted on an isolation plate. The isolation plate should be mounted to the bay floor. Use isolators that with bolts that do not contact the pump, plate, or floor. You might think of something like this https://www.mcmaster.com/products/isolat...h-studs-6/ or like this https://www.mcmaster.com/products/isolat...ushings-6/

Now here is the key part. The plate material and thickness is really important. You may have to try different thickness steel plate to get the result you want. The idea is that the plate decouples the vibration of the pump. In different words. Some vibration will transmit from the pump to the plate, if the plate is the correct thickness and weight it will not vibrate at a harmonic frequency with the pump thus negating much of the vibration of the pump from transferring through the next isolators to the bay floor. I cannot tell you which isolator will work best, and I cannot tell you what the thickness of the plate should be. That is some specialized engineering. So you have to experiment.

Or buy a JunAir oil based compressor. You will faint at the price, but you will never know it’s on.

Right now I'm setup with piece of plywood that has rubber on the bottom and is stuck to the floor with silicone.  In between that board and the compressor is some rubber bushings.   From the sounds of what you're saying I should have a piece of steel of a yet to be determined thickness mounted to the floor with rubber bushings in between it and the compressor?  If that's the case how would one best go about attaching the bushings to the plate, would I need to tap and die and then screw the bushing into it that way?

And I'll bite on the JunAir proposition...can someone shoot me an appropriate model that would work for this purpose.  A silent compressor would be pretty stellar.  On a related note I'm moving into a larger stall this winter and my biggest task is once temps get cold to really go over this thing to get my times back up to where they should be.  I'm at about 1.5 hours in full summer heat, so we've got a couple leaks to track down somewhere other than where I've already checked.

[HoosierDaddy]

My Junair is not completely silent but it’s very quiet. It has spring/rubber feet built right on to it.      [attachment=14592

[Richard]

Brad,

Yes on needing a piece of something heavy between the compressor and the floor. Plus the compressor must be on isolator mounts to the heavy plate, AND the plate must be on isolator mounts.

Look carefully at the links I posted. The mounting bolt goes through the mount in such a way that the bolt does not provide a solid link to the plate.

On the other hand. This is very very quiet. https://www.ebay.com/itm/176446828811?ch...H4QAvD_BwE

[hypoxia]

I gave a lot of thought about installing a Jun-Air.  Instead I repaired all of my air leaks, now the compressor only comes on when doors are operated.  I still give the Jun-Air some thought when in a campground since the compressor must annoy the neighbor on that side.  The best improvement I did on the Thomas compressor was installing a muffler on the unloader as described in this thread. Compressor Unloader Muffler  The unloader is completely silent now.