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WindowshakerA/C: drainpipe /pan/problem solved!

PostPosted: Sun Mar 17, 2013 12:54 pm
by working on it
  • I bought a LG 5012j A/C unit yesterday, to be permanently mounted thru the wall between the sleeping area and the galley/storage area. It will be mounted in a galleyside sealed box with ambient air intake (for the chassis cooling) and exhausted air with separate vents to the outside. The system can run with the hatch closed (park 110v powered), but the hatch will need to be open for the slide-out generator to power it.
  • I also have 4 window A/C units at home (replaced the inefficient un-"zoned" central unit), used as "zoned" and time/temp variable units. I'm in the country and appearances don't matter here/ to me. They are of different BTU ratings and brands. My question is this: some don't have any overflow of the water condensation, so no outside drip-over...some do (a lot). The model I purchased LG 5012j doesn't come with a drip/drain tube attachment like it's brother the LG 5012(no "j")
  • Since I'm going to seal this unit in a box (of course, with the correct angle-back), with a sealed bottom, should I just rely on a self-fabricated draintube, waterproof the bottom inside of the box (Plasti-dip?), add a drainpan (say a 10x17x1.5 cake pan or such, with a tube) under it, or combinations of the above? I have 2" of space to work with. I'm leaning toward the tube and Plasti-Dip combo. All the seams of the box will also be HVAC foil taped , w/ Simpson angle brackets to hold it together. Easily removeable for cleaning/drying after use (if needed). I just don't want to build it twice! Anyone have some experience with this?

Re: Windowshaker A/C: drainpipe or pan underneath?

PostPosted: Sun Mar 17, 2013 6:16 pm
by 48Rob
I vote for a drain pipe.

A pan will work fine for normal operation, but a full pan when you are on the road will not stay in the pan...

Rob

Re: Windowshaker A/C: drainpipe or pan underneath?

PostPosted: Sun Mar 17, 2013 9:45 pm
by working on it
  • 48Rob- I think you're right about the pan (besides, my wife would scream if I stole one of her Airbake pans). I'll just drill (very carefully) a hole in the left rear (streetside) of the unit, and insert a drain tube. Already started the install; I have now cut the rear wall, inserted the A/C (at a 3.5 degree downward angle), started to seal the wall and trim out both sides. Tested it too...works great (no rattles or shaking...it's supported by 3/4" ply all around...besides, no windows yet, haha).
  • Next step is to fabricate the drain, build the enclosure, and re-purpose a Speedi-boot HVAC vent register (90 degree turn) for the exhaust ducting. Need to order two vents (Redline 9139), the speedi-boot, a duct splice, and insulated flexible ducting to match. As an added touch, I'll put angle gauges on the unit to ensure that the trailer is oriented to help the A/C drain.
  • 103366 inside cabin;A/C thru bulkhead, taping and frame to follow
  • 103367 rear view; taped, with frame, supports, drain pan to follow

Re: Windowshaker A/C: drainpipe or pan underneath?

PostPosted: Sun Apr 14, 2013 10:03 pm
by working on it
  • Finished my A/C installation today...drain pan/drain pipe and fully contained exhaust ducting. With shore power, the A/C can run at night with the rear hatch closed and locked!
  • 104739 rubberized drain pan under A/C, w/ drain tube (on left)
  • 104740 note the downward-sloping angle of ducting, so any moisture in duct drains out
  • 104741 reduced duct size to fit into external vent (enlarged later on)
  • 104742 external vent on right side rear of trailer
  • 104744 inside cabin view of A/C w/air delector on top
  • For details read my descriptions in my gallery.

Re: WindowshakerA/C: drainpipe & pan!! PROBLEMA!

PostPosted: Sun May 19, 2013 8:04 pm
by working on it
  • While cleaning the cabin of sawdust from cutting out window spaces, I cranked up the A/C (since it was 95 degrees in the garage, and hotter with me in the cabin, even opened up). Blew nice and cold, as previously tested a month ago, then the compressor cycled off. Five minutes later, on for 5 then off again.
  • Suspecting a problem, I put a temperature probe (meat thermometer!) in the exhaust vent slots and saw that when the temp hit 135 degrees > compressor shutdown; repeated test to confirm results. The window shakers are set to do this at that temperature, I read somewhere, and was originally going to place a helper fan in the ducting to evacuate the hot exhaust faster. but I thought that my ducting was large enough to naturally aspirate that hot air.
  • Looks like I need a blower in-linehttp://www.ebay.com/itm/6-Aero-Flo-240-HIGH-CFMs-inline-Duct-Air-Booster-Fan-/330351699650. Anyone experience a thermal shutdown with their A/C before? Will this work for me, if done properly?

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Mon May 20, 2013 6:51 am
by TPMcGinty
Dang! Nice job! Can I hire you to do my exhaust ducting?! That's one of the problem areas that I'm having in my AC installation. Where did you get the flexible ducting?

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Mon May 20, 2013 8:14 am
by Shadow Catcher
Many/most AC units are 'slingers' the condensate picked up by the outside fan and used to help cool the fins. They are however a bit noisier and I will usually drill a hole to allow this to drain. One of the reasons is that standing water in an AC leads to growing (green and fuzzy and slimy) stuff you do not want around.

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Mon May 20, 2013 9:40 pm
by working on it
TPMcGinty wrote:Dang! Nice job! Can I hire you to do my exhaust ducting! That's one of the problem areas that I'm having in my AC installation. Where did you get the flexible ducting?


Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Tue May 21, 2013 11:47 am
by TPMcGinty
Do you have any kind of air flow around the coils in the AC unit (into and out of the vents on the side) or is the air stagnant?

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Tue May 21, 2013 11:56 am
by TPMcGinty
working on it wrote:104348


How did you attach the Speedi-Boot to the back of the AC unit?

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Tue May 21, 2013 1:36 pm
by KCStudly

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Tue May 21, 2013 9:10 pm
by working on it
KCStudly wrote:Looks like a jelly roll pan (a cookie sheet with sides on it).

http://www.walmart.com/ip/Farberware-Nonstick-Carbon-Steel-Baking-Sheet-Triple-Pack/11417015?findingMethod=rr

You're close http://www.walmart.com/ip/Mainstays-3-Piece-Cookie-Sheet-Set/10174458?findingMethod=rr. Plus two pieces of 1/2" oak (painted black) screwed to the cookie sheet and also to the wall frame to support most of the negligible weight , then foil-taped in place. The boot and cookie sheet assembly were screwed and taped together before taping to the A/C.
TPMcGinty wrote:
working on it wrote:104348


How did you attach the Speedi-Boot to the back of the AC unit?
Do you have any kind of air flow around the coils in the AC unit (into and out of the vents on the side) or is the air stagnant? Do you have any kind of air flow around the coils in the AC unit (into and out of the vents on the side) or is the air stagnant? Answer: The ambient air in the galley (whether hatch is closed or not) is supplied thru a screened 6" dia vent (also serves to ventilate the gas fumes and/or battery gases in that area) next to the chassis cooling louvers (90% uncovered by framework and tape). Since all the exhaust is directed away from those louvers, and cannot be reabsorbed by them, the unit should run cooler than one exposed to a hot breeze back feeding it. I just need to extract the exhaust faster, more completely, to lower the temp inside the ducting. Theory is good, but the execution is lagging.

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Wed May 22, 2013 6:53 am
by TPMcGinty
working on it wrote:http://www.walmart.com/ip/Mainstays-3-Piece-Cookie-Sheet-Set/10174458?findingMethod=rr. Plus two pieces of 1/2" oak (painted black) screwed to the cookie sheet and also to the wall frame to support most of the negligible weight , then foil-taped in place. The boot and cookie sheet assembly were screwed and taped together before taping to the A/C.

How did you attach the Speedi-Boot to the back of the AC unit?Do you have any kind of air flow around the coils in the AC unit (into and out of the vents on the side) or is the air stagnant? Do you have any kind of air flow around the coils in the AC unit (into and out of the vents on the side) or is the air stagnant? Answer: The ambient air in the galley (whether hatch is closed or not) is supplied thru a screened 6" dia vent (also serves to ventilate the gas fumes and/or battery gases in that area) next to the chassis cooling louvers (90% uncovered by framework and tape). Since all the exhaust is directed away from those louvers, and cannot be reabsorbed by them, the unit should run cooler than one exposed to a hot breeze back feeding it. I just need to extract the exhaust faster, more completely, to lower the temp inside the ducting. Theory is good, but the execution is lagging.


Thanks for the info on the cookie sheets. I love the simple solution. Now it's time to measure the back of my AC and figure which one will work! I didn't use as large a side vent inlet to allow air to my AC. I used one of these:

http://www.etrailer.com/Enclosed-Trailer-Parts/Redline/HMAV2-AVT2.html

I was worried about water getting in the side of the trailer so I got this one. I also added a large 12 volt computer fan to help suck in the fresh air. I hope it is enough.

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Wed May 22, 2013 8:26 pm
by working on it
  • Took off the flex hose and insulation this evening. I wanted to test the system to see if exhaust flow with less restriction would allow the A/C to run more than 5 minutes. The ambient air temperature in my garage was about 5 degrees cooler, not a major difference. The A/C was set at the same 75% level, the thermometer was laid inside the end of the Speedi-Boot (not the vent), and the unit was turned on...after 20 minutes it was still running!
  • The temp reading was 140 (5 more than the previous high) but still no shutdown! Of course, the thermometer was reading the temp of the heated metal, not the actual exhaust air temp, which was probably lower. The metal boot was in a "heat soak" condition (which is familiar to any of you old school Chevy small-block enthusiasts), and the reading was false. The best thing about the test is that the heat stabilized at 140 for the final 5 minutes of the test, and still it ran. So the A/C is in good working order...the solution is out there.
  • I added into my gallery 9 photos with more detailed comments about the system components and assembly, and the run test as well. Here are the photos:
  • 106947106948 with insulated ducting removed, exhaust from boot goes thru wall exit
  • 106949 correcting the angle for smoothing out the airflow
  • 106950106951 A/C exhaust into boot; exit vent (showing inner rainshield)
  • 106952106953 vent on other side for ambient air intake; support framework
  • 106954106955 using meat thermometer to measure exhaust temperature

Re: WindowshakerA/C: drainpipe & pan!! Problema!

PostPosted: Wed May 22, 2013 9:59 pm
by asianflava
This is my experiences with using a window shaker unit. The rear of mine is in a pan, but I ran a tube from the drain straight to the piping.

Here is the problem, The chassis of the a/c unit itself acts as a pan so that it can direct the condensate towards the hose barb, if you notice the hose barb doesn't go all the bottom. There are times when some water stays in the pan since it doesn't reach the height of the drain. At the first stop, it sloshes forward and leaks thru the front. Granted it's not a whole bunch, maybe a quart at the most, but a wet bed is annoying. What I need to do is remove the unit and drill drain holes in the bottom of the unit. Although it is possible, it would be a big PITA.

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