An Unexpected Visitor - We Needed A/C Vent Screen Repair

BrianZ

This little project started with trying to mount a new indoor/outdoor thermometer that requires running a wire to the outside for the outdoor sensor.  I thought our best option might be to find a path through the A/C cabinet which has two openings to the outside.  I removed the wood trim frame around the A/C unit to get a look inside the cabinet & got this view..

I could see the dark fan at right mounted on the ceiling under the roof vent, but what's that lump sitting on the A/C unit to the left of it?  

A closer view showed a mud dauber wasp sitting atop his castle, but how did he get in there with screens inside both the roof vent and the side wall vent?  Upon inspecting the outside vent, I found the upper right corner of the screen was loose where it had either been poorly installed, pushed loose somehow, or there was a failure of the adhesive on the 4 pieces of aluminum foil tape used to secure the screen.

I had to remove the 4 screws in the vent cover on the outside driver side wall, then cut through the caulking around it, before I could pull the cover off.  The loose edges of the tape did not feel sticky at all, like it had dried out & lost its adhesion.  Then I went inside & sprayed the mud nest with wasp spray aimed through the opening in the cabinet.

(Advice: wear gloves & eye protection, move seat cushion, and have a rag handy, so when some of the spray hits the cabinet & starts running down the side of the cabinet & is about to start dripping on the seat cushion, you won't need to catch it in the palm of your hand. 😉)


Above are the "before & after" shots after removing all the old foil tape, and replacing the screen using a single long strip of 3M white duct tape wrapped completely around the vent & overlapped for strength.  I also added pieces over the top of the screen behind metal frame supports at the ends & in center, to prevent the screen from being pushed in.


Another before & after view.

The cover is back on, but I'm not sure yet how to deal with removing the nest, but suggestions are welcome.  It's at least a couple inches tall, while the opening is only about 3/4", so it would have to be broken up whether the unit is removed or not.  Also not sure how to remove the A/C unit either, though that seems like what needs to be done for cleaning, as I wouldn't want any mud to end up in the drain pan drain tube.
By the way, the wasp was out running errands when I sprayed, and afterwards I observed outside from a distance & saw him return & fly around the opening without the vent cover, but he was repelled by the odor, despite trying several times to enter.  After an hour or so I reinstalled the repaired vent cover.

jkjenn

Oh, yikes! Shop Vac with attachment?

BrianZ

Yeah, that could work, but I wonder if it could be done without a piece of mud rolling off the side & into the drain pan.  Best option for now.

ericnliz

@BrianZ, The A/C is removable by taking the front wood frame off to access the mounting screws for the unit. Slides out, & you can have better access to the whole enclosure. That way if something does fall into the drain pan, you'll still be able to get to it. @Michigan_Mike replaced his A/C & shows how it comes out. Can't remember the name of the posting though. Might search A/C replacement & browse through.

Ratkity

Shop vac if ya got it. But knowing me?

The ultimate redneck solution would to be take my wood saw (NO! put down the hatchet!), and cut the little sucker in half and then slice the rest off.

You'll have a chance to knock out the pieces with a very long screw driver (my way), or go the shop vac way but you'll probably need to make smaller pieces (banging at it as hard as you can with a screwdriver blade is satisfying). 

Remember, just because the big wasp can't come back doesn't mean there aren't leeeetle baby waspies that'll hatch. Bzzzzzzzzz! (and the wrong kind of Bzzzzz too! )

Sharon_is_SAM

@BrianZ, try “Air Conditioning Change Out”.

BrianZ

Thanks for all these great tips, including how to find Michigan_Mike's instructions.  I do have an extra long screw driver, so may try that first, but I plan to take out the AC unit to make sure everything is clean. 
Let's see, I think there are more opportunities for lemonade here; like didn't someone suggest lining the left inside wall with insulation board, and maybe something could be done with the vent cover to make a cover for it before recaulking.

Verna

By the way, mud daubers are not supposed to be able to sting....or so I‘m told. But, since I am so allergic to wasps and yellow jackets, it doesn’t matter because I'm going to run and scream like a little girl!

Seriously, Brian, use a screwdriver, a dowel rod, or whatever and get the nest out of there as soon as possible. One fell off the garage door at my storage unit two days ago and the “babies” were starting to look like adults. It’s that time of the year. 

BrianZ

I did spray the mud nest, so hope that will kill any contents.  I also found my 15" long screwdriver, so plan to break it up with that & hopefully use a flat attachment on the vacuum to remove as much as I can before taking the unit out for cleaning.

BrianZ

And the rest of the story...

A couple of taps on the long screwdriver placed at the bottom center of the wasp nest popped the whole nest loose, so I just pushed it over the left edge into the drip tray, lifted the AC unit out & cleaned up.  There weren't even any screws to remove & the cord was long enough to set it on the table without having to remove the socket & cord. I did flip off the AC breaker & pulled the fan fuse out first.


I set the nest back on the unit to show where it was located, then I took it out on the driveway to chip it apart to see what was inside.  There were about 3 or 4 closed chambers, but I was totally surprised by what I found inside..  


Instead of only wasp larvae, it was packed with many dead spiders.  I did find a few larvae like the one near center in this shot.  Apparently, the wasps can paralyze the spiders, then stuff them in the nest for food before laying the eggs and sealing it up.  Very weird!


After vacuuming inside the cabinet & wiping things up with a wet rag, I got my thermometer wire run through the cabinet to the roof vent.  The green line shows the path I used - a small drill hole in the bottom of the AC fan switch plate got my sensor cord into the wall & inside the cabinet, then above the fan and out the roof vent.


Checked the slope of the drip pan, and as expected it is sloped away from the wall, but only slightly towards the front.


Had to drill a hole through the edge of the board above the fan to run the wire up the air pipe to the roof.


There was a tiny mud nest on the vent screen, which I removed.  I cut one edge of the screen to pass the wire through & tied it to the post that the cap is screwed onto, so the temperature sensor lies under the shade of the cap.

Ratkity

Geesh! Two wasp homes. Surprising about the spiders!!!! ew.

I like what you did with the temp wire. Don't you worry the heat being pushed out the vent will affect the actual outside temp or am I confused where you put it?

BrianZ

Hey, @Ratkity, I put the sensor under the edge of the vent cap - outside, but in the shade.  Not ideal, best best available.
How is heat being pushed out the vent?  I thought the AC fan was supposed to be drawing air into the AC cabinet, not pushing it out.  As far as the temp readings, it was a sunny day, so hot up on the roof; however, I think this cheap thermometer is reading too high.  It should have read closer to 80 in the shade, but will have to check again in the morning.

Ratkity

@BrianZ, that's why I thought I was cornfuzzled - I couldn't remember if the little fan drew air out or pulled air in. In the shade is good, but I wonder if it gets hot under the cap (Ya can't win, can ya?). It's probably the best place to put it. You can turn on the fan without the AC working and would probably get a fairly accurate outdoor temp. The air flow may mitigate being under that cap. Of course.... Jenn could probably tell you how to set up a spreadsheet to monitor your roof temp verses under shade temp next to the camper and then reported ambient temp....

BrianZ

Yes, @Ratkity, that's what I was thinking, that I could turn on the A/C fan to pull in outside air over the sensor for a more accurate reading. Otherwise, there could be some inside air escaping through the vent.  I did a comparison early this morning before there was any direct sun with two other outdoor thermometers on different sides of the house which read 68.4° & 68.9°, while the T@B vent sensor read 69.9°.  However, I forgot to test with the fan on, and the inside was reading 71.6°, so may need to try again.  I consider the 68.4 reading as my reference, because it is a calibrated Davis weather station sensor that is more ideally situated on a north facing side of the house, over ground with vegetation, and inside a radiation shield as part of my rooftop weather station.  Still, the accuracy of these sensors is only within a few degrees, but more dependent on location.
If the sensor's wire was long enough, I could have also run it down the drip pan drain tube & out the bottom, but it would be less protected.

Edit:  forgot to include photo of final mounting of temp sensor inside vent..

BrianZ

Before replacing the vent, I revised my previous vent cover made from a corrugated plastic yard sign (like others have previously documented).  I had used the 3M dual lock plastic velcro-like adhesive strips previously, but I found it difficult to remove without the adhesive coming loose.
This time I used the strong magnets, & glued six very powerful 1" round rare earth magnets on the inside..

Source:
ZHW Neodymium Magnets N52-Rare Earth Magnets – Round 1" D x 0.2" Thin Magnetic Discs – Craft, Science Or DIY Magnets Pack of 15 https://www.amazon.com/dp/B07DLNQPT5/ref=cm_sw_r_cp_apa_zi2DBb6K8RYF2


Replaced vent & caulked around the top & sides.  The vent appears to be metal, maybe aluminum, but not magnetic, so magnets must be glued.


On the inside of my plastic vent cover I glued on these steel washers, which match well strength-wise with the magnets.  I used this very strong 3M E6000 adhesive..
E6000 231020 Adhesive with Precision Tips, 1.0 fl oz https://www.amazon.com/dp/B00JP3X9WE/ref=cm_sw_r_cp_apa_tt2DBb1EFVKD3
I prepared the washers & magnets by sanding the sides to be glued, cleaning with rubbing alcohol, plus coated the exposed surfaces of the washers with fingernail polish to prevent rusting.  Alignment of round magnets & washers is not what one might expect - they resist being centered together & prefer to have the center of one over the edge of the other.


This combination worked very well to keep the cover tight against the wall.  The edges are lined with a double layer of adhesive window/door foam insulation strips to make up for the thickness of the vent.  We plan to use the cover for winter storage or while camping in cold temperatures or while washing the trailer.

jgram2

Very nice @BrianZ - you’ve been busy as a bee! 🐝 

BrianZ

Buzz, buzz, thanks!  

ChrisK

Nice work. I wondered what the AC fan looked like and if I could retrofit it to my T@b. 

BrianZ

I would think it should be a relatively easy retrofit, @ChrisK,  provided you have the strength to lift the A/C unit out of the cabinet, and can do some basic wiring for the switch. It would require drilling a hole in the wall to mount the switch & finding the wire pair to tap into.  Mine is connected into 10Amp DC circuit #5, which includes the ceiling fan and Alde.  NüCamp can probably send you the parts.

Ratkity

Just don't forget to take it off when you use your AC hehe. I did that once and wondered why I wasn't getting any air.

BrianZ

Forgot to mention, @ChrisK, that the wire color on my fan circuit is green. Here's what the wiring looks like behind the switch..
The wire coming up out of the left corner of the hole is the +12V green supply wire from the converter compartment that feeds both the switch and a second wire that continues up to supply the ceiling fan.  The single green switch output wire from the other switch terminal continues up to feed the A/C fan.  Of course, white wires are common ground & connected together.
Ignore the single white wire going down the wall, which is my outdoor temperature probe going out the roof vent.

ChrisK

Yeah, I'd have to run all my own wires. None of that exists in my T@b. No biggie though.

Sharon_is_SAM

This from a friend’s RV.  It has been successfully evacuated without anyone getting hurt😀

ericnliz

@Sharon_is_SAM......Wowser!

Ratkity

WOW EEEEP!

Sharon_is_SAM

It is really kind of awesome that they can make something that beautiful.  Doesn’t it look like a brain?

gulfarea

I bought the roof vent screen only to find NuCamp was ahead of me and had installed it already! thanks NuCamp. Art

ColleenD2

This is an incredible story and I appreciate all the photos along the way. We laughed, we cried, we ran away screaming like girls. It has everything!

BrianZ

Glad you enjoyed it, @ColleenD2.
This spring I forgot to remove the big magnetic a/c cover from the driver side which had been on all winter for storage.  I only discovered it after arriving at a campsite when we needed to use the A/C, so at least I know for sure that those super-magnets are every bit as strong as I thought.  I never really intended to use it for travel but keep it with the trailer in case ever needed for cold weather or dusty conditions.

ChanW

So @BrianZ, the strength of those magnets doesn't make it impossible to remove? I'd think your 'signboard' would bend!

gulfarea

I made up a hatch on this T@B and my first T@B, glassing the wood & using 32 1/4 cylinder magnets. Just finished a 3,100 mile trip & the hatch never moved. Tested it out on nearby RR tracks that shook my fillings out! Keeps weather & dust out. Art