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Author Topic: Basement AC air flow  (Read 315 times)

sgkane

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Basement AC air flow
« on: May 26, 2017, 09:37:25 AM »
We were in Houston and the basement AC started making noise, which sounded very much like either a bad bearing or the squirrel cage was coming loose. Knowing that it wasnít going to get any better and we were in Houston I had better get busy. I didnít document the repairs because itís been so well document in the Duner report (search ďDunerĒ on IRV2.com) . 
Since weíve owned this MH (little over a year) the AC has struggled especially when temps rose above 95 and when the temps hit 100 forget about it. I didnít think that much of it because of what Iíve read here and elsewhere on the basement units and weíve been talking about adding a roof top unit.
Not knowing exactly what I was going to find when we got the AC out, I ordered a new motor, fan and picked up a bearing at Grainger. Pulling out the unit went pretty much like it shows in the report with the foot notes at the end for our MH. What I found when we got it out surprised me. The AC pulls air from inside the bus through the coils and out to the ceiling duct work. Where the plastic duct for incoming air meets the unit is simply a compression fit with a foam seal. Nothing else holds it together other than the unit itself pushed against the seal. In our case that foam seal apparently had started to disintegrate over the years and that foam was being sucked in to the coils. With the exception of an area about the size of my fist the coils were completely blocked with sticky foam.
So in addition to the parts replacement that fixed the noise, I cleaned the cooling fins with a soft plastic brush and replaced the seals. What a HUGE difference. We are in Texas still and the temps have only been in the low 90ís but I canít get over how much cooler and better airflow we now get. As for the noise it turned out to be just the bearing had gone bad but since I ordered all the parts everything got replaced.
Iím posting to mention that a poor producing basement AC unit might simply be plugged coils. You simply cannot see that side of the coils without removing the whole AC unit.
2004 Itasca Horizon 40AD

Sailorkane

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Re: Basement AC air flow
« Reply #1 on: May 26, 2017, 10:15:41 AM »
Thank you very much for the information.  Its posts like this one that help the rest of us figure out problems when they occur.
2003 Winnebago Journey DL 39WD, Freightliner, Cat 3126E 330HP.  Diesel Pusher.

John Canfield

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Re: Basement AC air flow
« Reply #2 on: May 26, 2017, 12:07:58 PM »
.... In our case that foam seal apparently had started to disintegrate over the years and that foam was being sucked in to the coils. With the exception of an area about the size of my fist the coils were completely blocked with sticky foam.
So in addition to the parts replacement that fixed the noise, I cleaned the cooling fins with a soft plastic brush and replaced the seals. What a HUGE difference. ....
Interesting. I need to have a look at my evaporator coil. Just redid much of that ducting where it leaves the AC unit, replaced sticky tape with mastic and fiberglass tape.
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
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catblaster

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Re: Basement AC air flow
« Reply #3 on: May 26, 2017, 12:19:17 PM »
   I found the original foam gasket to be bad also, back when I first pulled my unit several years ago. Replaced it with a homemade gasket made from expanded neoprene, that one did not deteriorate but compressed to the point it no longer pushed back against the duct opening. This last time it has been replaced with a poly expanded foam much like that used in shipping containers.  Pulled the unit again last week and found this one to be holding up much better. The foam that is used from the factory and those used to seal camper shells to a truck bed will break down comparatively quickly.

   I'm getting to where I can pull the unit without breaking sweat. It has been out 4 times in this past month.
Will and Jane
95 Winnebago Luxor

NoMoreAZ

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Re: Basement AC air flow
« Reply #4 on: May 29, 2017, 04:07:38 PM »
   I found the original foam gasket to be bad also, back when I first pulled my unit several years ago.
   

Original foam gasket bad here also. Used MD Premium Sponge Rubber 3/8T x 3/4W black, comes in green bag (still I think). Can find at HD or Lowe's. Sticky side to, in my case, plastic ductwork that attaches to HP. After ductwork attached to HP, taped all around with foil tape.

One may wish to change the Phillips head screws used originally to fasten duct to HP to hex head screws. Probably able to use wrench or socket where screwdriver, even offset type, will not go.

As to coils and increased air flow... Purchase a fin comb. I use mine on the outside (condenser), the inside set, and the side radiator for the engine.
NoMoreAZ
2006 Itasca Horizon 40KD
2004 Honda CRV

 

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