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Topic: Heat Pump Replacement (Read 485 times) previous topic - next topic

Heat Pump Replacement

Hello all, I know this topic has been beat to death but hear me out.  My front ac is extremely loud.  Lots of vibration and rattling of the metal baffles.  And it shakes the whole coach.  Middle one isn't exactly quiet but it is very tolerable without any rattling.  The rear ac has a compressor that is so quiet that I often can't hear it running.  I have duo therm heat pumps that I do believe are original.

I hear lots of complaints about noise with the new 401 refrigerant penguins with plastic ducts.  But reading through the complaints I am getting the feeling the complaint is about the air noise and not the compressor noise.  The air noise doesn't bother me AT ALL.  The compressor noise is what is driving me crazy. 

Can anyone comment on the compressor noise of the newer units?  I'm gathering I'll have to replace my thermostat with a CCC2 unit as well as the control boards in the 2 acs if I am to replace one unit so it's a rather expensive proposition.  Is there a board for the thermostat or is that just a basic 2 wire in each ac housing as I am lead to believe?  Anyone do a 13.5k to 15k upgrade?  I am considering it as on the 42' the front ac is pretty far back and the front of the coach can be warm even with the ac blasting.

Re: Heat Pump Replacement

Reply #1 –
I can't give any info on new units, but I had mud Dobber  nests in my squirrel cage and it was really out of balance and shook a lot. Removing covers and cleaning made a huge difference.
Scott
Scott and Kim Davidson
If you're going to be dumb, you got to be tough.
DEGOIWKY
Don't ever get old, it will kill you
June 30, 2020
2001 U320 3610 Barn find
Build 5834

Re: Heat Pump Replacement

Reply #2 –
Quote from: dsd –
I can't give any info on new units, but I had mud Dobber  nests in my squirrel cage and it was really out of balance and shook a lot. Removing covers and cleaning made a huge difference.
Scott

I've had that happen before in the rear most one.  Turned out to be a dead frog.  But like I said that is air mover noise whereas my complaint is compressor noise.

Re: Heat Pump Replacement

Reply #3 –
Quote from: Mark D –
my complaint is compressor noise.

Mark,

It could be as simple as the compressor mounting isolators need to be replaced.  If these units are OEM then the isolators are sure shot letting the bottom of the compressor hit the mounting pan.  If they are cooling/heating just fine then this can be a $5 fix.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Heat Pump Replacement

Reply #4 –
Quote from: Pamela & Mike –
Mark,

It could be as simple as the compressor mounting isolators need to be replaced.  If these units are OEM then the isolators are sure shot letting the bottom of the compressor hit the mounting pan.  If they are cooling/heating just fine then this can be a $5 fix.

Mike

Thanks for the suggestion.  I did in fact check this as I saw "quiet kits" that include new isolators.  The isolators are in great shape and it doesn't look to be hitting the bottom.  That said, if there was ultra high quality fatter isolators around that may do the trick.  Especially because the unit does still work fine.  The foam insulation lining the baffles is breaking down but nothing a bit of styrofoam couldn't fix.

Re: Heat Pump Replacement

Reply #5 –
Also look at the rubber grommets for the fan motor mountings.  These also wear out and cause vibrations and noise.  I replaced the ones on my front ac recently and it helped with the vibrations and noise.
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Heat Pump Replacement

Reply #6 –
Quote from: folivier –
Also look at the rubber grommets for the fan motor mountings.  These also wear out and cause vibrations and noise.  I replaced the ones on my front ac recently and it helped with the vibrations and noise.

Thank you for encouraging me to take a second look!  I noticed some issues I didn't see last time.  I've got it "fixed".  It now makes the same amount of noise and vibration as the other 3.  What I found was that the compressor was mounted to a plate which was then mounted to the floor pan of the ac unit.  The floor pan dampers looked ok but when I pushed down I could hear a slight tink.  The vibration isolators that the compressor itself mount to were fairly collapsed.  I kept messing with it and I figured out that when you shook it enough the pipe coming out of the front touched the floor pan.  The compressor mounting plate also was touching the floor pan.  I took two pieces of heater hose and shoved them under the suspect isolators to bring the height up so that pipe couldn't touch.  I also shoved two more under the front and rear of the side of the pan that appeared to be touching and it is MUCH quieter. 

How do you service those isolators without bending the copper pipe?  Can the copper pipe handle that amount of bending without breaking even at its advanced age?

Also does anyone have a part number for both the pan isolators as well as the ones that connect to the compressor itself?

Re: Heat Pump Replacement

Reply #7 –
Quote from: Mark D –

How do you service those isolators without bending the copper pipe?  Can the copper pipe handle that amount of bending without breaking even at its advanced age?

Also does anyone have a part number for both the pan isolators as well as the ones that connect to the compressor itself?

To get the compressor high enough to replace the isolators, I removed the sheet metal ducting and raised the evaporator up a bit.

I didn't replace the isolators. I placed cushioning washers McMaster-Carr under the original isolators.

Greg
Greg & Cathy
2000 U320 4010 DGFE Build #5650
Had: 1999 Tradewinds 7370

Re: Heat Pump Replacement

Reply #8 –
That's essentially what I did with pieces of heater hose except I slit them and shoved them under.  You could simply slit the cushioning washers in there so you don't have to lift it any higher than the clearance you need to push them in.  I think I'll order some of those and give that a shot for a better repair than what I've done so far.