WindowshakerA/C: drainpipe /pan/problem solved!

[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?

 

[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

 

[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.
• 
  inside cabin;A/C thru bulkhead, taping and frame to follow
• 
  rear view; taped, with frame, supports, drain pan to follow

 

[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!
• 
  rubberized drain pan under A/C, w/ drain tube (on left)
• 
  note the downward-sloping angle of ducting, so any moisture in duct drains out
• 
  reduced duct size to fit into external vent (enlarged later on)
• 
  external vent on right side rear of trailer
• 
  inside cabin view of A/C w/air delector on top
• For details read my descriptions in my gallery.

 

[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?

 

[baron1]

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?

 

[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.

 

[working on it]

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?

• Home Depot, naturally. http://www.homedepot.com/p/Master-F...lver-Jacket-F6IFD6X300/100396935#.UZrWlVko5tQ Thanks for the compliment, but until I solve the thermal overload, I feel that it is premature. I was proud of my ingenuity, but obviously it's a work in progress.
• I also used a collar to fasten to the wall, an adjustable angle duct to straighten the angle to keep the flexible duct from folding closed, and of course the Speedi-Boot 90 degree register vent boot to start it all http://www.homedepot.com/p/t/202542...0051&N=5yc1vZ6cfZ6cf&R=202542047#.UZrcLFko5tR.
• 
  
  Speedi-boot vent register, attached to cookie sheet, then to A/C
• I'm thinking that the 90 degree bend, and the flow restriction when exiting the louvered vent http://www.etrailer.com/Enclosed-Trailer-Parts/Redline/9139.html is enough to cause the overheat.
• 
  louvered, rainproof vent may be restricting exhaust airflow
• I'm going to get the hi temp in-line blower and connect it to the collar at the wall. If that doesn't do it, then I'll build a slanted deflector to keep the exhaust aimed up-and-out of the galley, remove the ducting, and forget about A/C operation with the hatch closed.

 

[baron1]

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?

 

[baron1]

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

 

[KCStudly]

Looks like a jelly roll pan (a cookie sheet with sides on it).

http://www.walmart.com/ip/Farberwar...g-Sheet-Triple-Pack/11417015?findingMethod=rr

 

[working on it]

Looks like a jelly roll pan (a cookie sheet with sides on it).

http://www.walmart.com/ip/Farberwar...g-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.

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.

 

[baron1]

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.

 

[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:
• 
  
  with insulated ducting removed, exhaust from boot goes thru wall exit
• 
  correcting the angle for smoothing out the airflow
• 
  
  A/C exhaust into boot; exit vent (showing inner rainshield)
• 
  
  vent on other side for ambient air intake; support framework
• 
  
  using meat thermometer to measure exhaust temperature

 

[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.

 

[KCStudly]

I'm wondering if a large computer case fan would work equally well, cost less, and be more quiet. Though maybe not heat proof like the dedicated HVAC unit you plan on adding.

Looks like you're on your way to getting it to work reliably.

Can you tell me more about your adjustable vent grille/diffuser? Where did you find it and what is the diameter of the screw hole pattern?

TIA

 

[working on it]

• KC-Its the same vent and butterfly that I used for interior ventilation. I got them at E-trailer.com http://www.etrailer.com/Enclosed-Trailer-Parts/Redline/9139.html. When installing them, I never measured the hole spacing, but I cut 5.5" diameter holes with my Roto-Zip, centered the outside louvered piece over the hole, and with the screws already partially screwed into it, marked their location by giving the vent a solid rap with my hand. The screw heads would indent the plywood exterior where I needed to drill the four butterfly mounting holes. I drilled 1/4" because I needed extra wiggle room to get all four started (never could match up 2 holes on a total of 16 spots (4 vents)). But, I never could drill in a straight line (I used Spax screws in those two spots, to catch the threads).
• I'm gonna use the duct fan in the duct, but I'll also add another case fan, much the same as I put in the cabin, except reversed flow to direct air over the A/C chassis cooling coils.
• 
  
  interior fans;120 cfm hi-static pressure versions
• asianflava- I haven't run my A/C long enough to get any overflow into the drainpan, or to the exit pipe. Also, I have a 4 degree back angle to keep drips out of the cabin, plus, I used foil tape to seal about an extra inch high on the sides, but made sure I didn't seal the bottom opening (a slight depression with about 1/4" hole). So I may not have a drainage problem (we'll see). And, I use three different window-shakers at home...two 15100 btu Frigidaires that really produce a lot of water, a 10000 btu Frigidaire that produces a little extra water (over the amount used in its internal splash-cooling), and an 8000 btu LG that seems to never produce any excess water (thus no leaks possible, nor mold problems).PS : the unit in the trailer is a 5000 btu LG , and I didn't detect any water yet in runs of 20 minutes, and 40 minutes (during cooler weather).
• Here are some personal comments about me and window-shakers, and why I want this one to succeed! All my units work great, and from my personal experience (having grown up and old in homes with and without central air) I prefer the window units. The sound, the airflow, are comforting to me. I almost wish that the 5k unit in the TTT made more noise!

 

[KCStudly]

Thanks for the link. The butterfly part is also available separately, and that is what I am interested in as a possible solution for my bulkhead vent fan.

 

[Tommy2bits]

On my teardrop, the AC unit was installed under the galley and separately vented, and I used a bathroom vent fan to duct the exhaust with a tube, but it was not enough CFM to do the trick. I ended up cutting a larger hole in the floor...

And then making a downward curve box to direct the exhaust and it worked great with no fans and in Texas heat...

Problem is that you now have a big hole in the floor so you need to build a spoiler in front of it to deflect water.

 

[working on it]

• After finishing everything else on the trailer today, I got back to addressing my A/C thermal shutdown problem, and drilled seven 3/8" holes in the louvered vent' rainshield to increase airflow- (airflow noticeably better, to my perception).
• 
  drilled holes in the vent's inner rainshield
• With the 110vac, 240cfm, 266 degree max temp, 6" diameter inline duct fan due in on Friday, I can rework the ducting and finish the HHRv on Saturday.
• 
  axial inside-the-duct fan; my hope for a solution
• 2bits Since I have no way of routing the exhaust downward from its location, nor upward due to the hatch to roof water shield, my choice is to stick with the current routing, and force the hot air out faster (if need to, I'll eliminate the inner rainshield entirely, and put a drain in the exhaust tubing, in the offhand chance that it'll collect there, since I'll route the tube downward towards the vent, if possible).