Wednesday, July 17, 2013

Inverted Frog: Adding Anti-Amphibian Countermeasures to an Air Conditioner

I got a new air conditioner for my Spartan project in March of 2013. It's the latest LG Mini-Split with a DC motor on the fan and compressor (I think). It delivers AC power to the inside unit. The idea of the inverter is to use the minimum amount of energy required to do the job. Instead of full blast or off, there are degrees in between determined by varying the DC voltage applied to the motor. So inside there is a big ol' power supply built on a circuit board, similar to the one for a computer, only bigger. It generates its own heat, which I guess is calculated to still be less than what is wasted by running everything full blast all the time.

My air conditioner works great for what is basically a solar oven. I thought I would put up shade sails because they would look neat and keep the sun off when the tree shade is lacking in the middle of the day. Turns out the cost of them and the trouble to take them down for every hurricane warning seemed more than just paying for extra electricity to run the new air conditioner.

This is the inside part of the
 air conditioner.

Of course nothing is perfect, not here in the Deep South where nature lives to challenge engineering creativity. On July 3 my air conditioner didn't work. The inside unit just flashed C-05 on the display that usually shows the temperature. I Googled that and found that it means communications error. Standard fix is a new communications board in the outdoor unit. I went out there and put my nose up to the place where the wire goes from inside to outside. I could tell by the smell that somewhere the smoke hath poured out from within. (This expression may be unique to me. There was a computer on the floor in the lab at my old work that had a post-it note on it that said "Smoke poureth out from within," which I thought was a very classy and precise way to say it was broken.) But I digress. I called the company that installed the air conditioner to see if the warranty covered labor. Yep. They would send the technician right out.


The technician quickly identified that I did indeed need a new control board. This one had catastrophically failed as a result of incinerating a tree frog. Tree frogs would seem to be pretty conductive, all clammy and capable of really good contact. Whenever I pick up a tree frog it reminds me of shaking hands with a sweaty baby.

There were two dead frogs on the control board, but I think the first one caused the failure and took the other one out with him.

The technician came back on July 12 with a replacement printed circuit board (PCB) assembly. The man at the office said he didn't tell LG about the frogs when they ordered it, but they do have to send the burned up one back. I am not confident they will remove the dead frogs. I feel pretty bad for whoever works in receiving at the end of that trip.

Here's a close up of the place where the frog shorted out the high voltage DC connector tab to the chassis ground trace running around the board. My friend Cheryl says PCBs start to get soft from 150 - 170°F. Chicken is done at 160°F, so extreme charring like this requires much more than that. So no wonder the circuit board is just completely gone under the frog. That's a giant aluminum heat sink underneath him. Which is why he was there. Sybarritic softie wants a place to hang out warmer than 77°F, the low here for the last few weeks.

Cheryl also told me the proper term for a hole in a circuit board from an arcing frog is "thermal event," not "smoke poureth out from within." Incidentally, PCBs are epoxy impregnated fiberglass, so that distinct smell is probably from the sooty remains of epoxy resin.

Here's the same part of the new circuit board. The part the arc obliterated is that blank board area between the tab labeled CN_PSC2 and ground, that band of copper and vias running around the outside of the board. There was no plane of copper under the frog to dissipate the heat. It just burned right up quickly. I guess the arc extinguished itself when the frog was exploded enough to open the circuit. None of the 2 fuses in the system were affected.

The technician got the replacement in place and tested it. Then he went away and I immediately turned it off for fear another frog would get in it. I wanted to make modifications that could be proven over the rest of the year, before the warranty runs out.


I think rather than try to keep frogs from going into the air conditioner generally I should just try to keep them out of this black plastic box. If I tried to build a cage of mosquito size screening around the whole unit, as suggested on Google+, it would need to be enormous to allow the kind of air flow required by the unit.
I'm going to try to block up the holes where the wires come in with this 3/8" backer rod. This is a foam that's intended to back up caulk joints. It costs about $4 for this package of way more than I need.


There, I fixed it.

I wasn't sure if it would work best vertical or horizontal. I did some of both. I can go look at it again after a few months of use and see if any fell out.


The lid is warped and sooty from the thermal event. Glad it didn't get hot enough to start it on fire.

The cover for the unit has foam on the end over the control board. I hope this means no frogs can get in there and muscle their way in by bumping the top off the enclosure. The plastic lid doesn't really snap on or anything. Just sits there. The metal cover is screwed down.

I put the top back on and fired up the indoor unit and cooled down my Spartan. And dehumidified it. The floor boards were starting to swell so much they cracked when I walked around.  

So that's how I frog-proofed my LG inverter air conditioner. I will update this if these countermeasures fail. What if it depended on that air flow around those wires and it overheats, even with that big aluminum heat sink underneath it?


I am worried it really isn't a great design for sitting in the sun on the south side of a building where temperatures routinely top 100°F. My other LG mini-split air conditioner is underneath my house, out of the sun, and with no inverter. I've never had a single problem with it in 8 years. But this one, even with openings around the wire for air flow it has to get hot in there. Is it a good idea for the plastic lid to be pressed up against that metal top? Easy maintenance, it's true. But that's just regular closed cell foam on there, not aerogel. I bet it gets at least as hot as in my car where I've measured temps of 150°F. (I've made peanut butter cookies on the dash before.) 150°F is the temperature the circuit board material starts to get soft. I'm about to put it through a hard environmental test the next few months. I guess I'll find out soon if it's fit for long term service in the Deep South.

79 comments:

  1. This comment has been removed by a blog administrator.

    ReplyDelete
  2. I absolutely love your blog and find nearly all of your post’s to be just what I’m looking for. can you offer guest writers to write content to suit your needs? I wouldn’t mind composing a post or elaborating on a few of the subjects you write about here. Again, awesome site! https://www.luxeac.com.au/air-conditioning-mosman

    ReplyDelete
  3. When you step out to buy the latest electronic equipment, you are bombarded with a series of acronyms, with each brand claiming superiority over the other. While it may sound like Greek and Latin to begin with, it really pays to understand Hvac repair south salem energy efficiency ratings when you're shopping for heating, ventilation and air conditioning systems.

    ReplyDelete
  4. Electronic channels : Connected to an electrical power source and as a rule divider mounted, electronic channels accompany a pre-channel that can gather bigger particles and just should be cleaned at regular intervals.
    heating repair patterson ny

    ReplyDelete
  5. This is such a great resource that you are providing and you give it away for free. I love seeing blog that understand the value of providing a quality resource for free. hvac repair north salem

    ReplyDelete
  6. I am hoping the same best effort from you in the future as well. In fact your creative writing skills has inspired me. air conditioner

    ReplyDelete
  7. Thanks a lot for your interesting article. I have been searching for such message for a very long time. Not all your content is completely clear to me, even though it is definitely interesting and worth reading. Sapulpa Air Conditioner Repair

    ReplyDelete
  8. Exact same thing happened to mine.

    ReplyDelete
  9. Wow, What a Excellent post. I really found this to much informatics. It is what i was searching for.I would like to suggest you that please keep sharing such type of info.Thanks Warmtepompen

    ReplyDelete
  10. Creased air channels are produced using engineered fiberglass also, the main contrast is the thickness of the fiberglass.Prijzen Airco

    ReplyDelete
  11. Diviner or occasional vitality proficiency proportion, rates the focal air conditioning unit. Airco

    ReplyDelete
  12. I’m going to read this. I’ll be sure to come back. thanks for sharing. and also This article gives the light in which we can observe the reality. this is very nice one and gives indepth information. thanks for this nice article... Airco

    ReplyDelete
  13. You make so many great points here that I read your article a couple of times. Your views are in accordance with my own for the most part. This is great content for your readers. Airco

    ReplyDelete
  14. Really impressed! Everything is very open and very clear clarification of issues. It contains truly facts. Your website is very valuable. Thanks for sharing. Airco

    ReplyDelete
  15. It's late finding this act. At least, it's a thing to be familiar with that there are such events exist. I agree with your Blog and I will be back to inspect it more in the future so please keep up your act. Airco

    ReplyDelete
  16. I wanted to leave a little comment to support you and wish you a good continuation. Wishing you the best of luck for all your blogging efforts. Airco

    ReplyDelete
  17. Very educating story, saved your site for hopes to read more! Airco

    ReplyDelete
  18. wow, great, I was wondering how to cure acne naturally. and found your site by google, learned a lot, now i’m a bit clear. I’ve bookmark your site and also add rss. keep us updated. Airco

    ReplyDelete
  19. Very interesting blog. Alot of blogs I see these days don't really provide anything that I'm interested in, but I'm most definately interested in this one. Just thought that I would post and let you know. Airconditioning

    ReplyDelete
  20. I truly appreciate this blog post.Thanks Again. Will read on... tks industrial profile

    ReplyDelete
  21. Nice information, valuable and excellent design, as share good stuff with good ideas and concepts, lots of great information and inspiration, both of which I need, thanks to offer such a helpful information here. Air Condition Repair Temecula

    ReplyDelete
  22. I like this post,And I figure that they having a great time to peruse this post,they might take a decent site to make an information,thanks for sharing it to me. asbestos inspection

    ReplyDelete
  23. In light of the assortment of requirements and the format of your home, the choices that may ascend, as pursues: hvac repair somers ny

    ReplyDelete
  24. An air conditioner is one of the most useful creations of the advanced world. It gives you peace during sweltering summer days and fends off you from the staggering warmth.aircon servicing

    ReplyDelete
  25. Have you at any point thought about what is happening inside your air conditioner? The fundamental thought behind any air conditioner is vanishing. At the point when a fluid dissipates it feels cool.heating repair north salem

    ReplyDelete
  26. The term HVAC stands for heating, ventilation, and air conditioning respectively. HVAC is implemented in home and automobiles for environmental comfort. Proper HVAC is extremely crucial for prosperous health and functional purposes.Honest Air Fayetteville NC

    ReplyDelete
  27. This is very educational content and written well for a change. It's nice to see that some people still understand how to write a quality post.! Portable Air Conditioner Cyber Monday Deals

    ReplyDelete
  28. There are numerous trustworthy temporary workers spend significant time in the establishment of air conditioning frameworks for both little and enormous homes. Airco

    ReplyDelete
  29. Excellent article. Very interesting to read. I really love to read such a nice article. Thanks! keep rocking. used sand blaster

    ReplyDelete
  30. This blog is so nice to me. I will keep on coming here again and again. Visit my link as well.. mini sandblaster

    ReplyDelete
  31. When your website or blog goes live for the first time, it is exciting. That is until you realize no one but you and your. Air Conditioning Repair in Los Angeles

    ReplyDelete
  32. I am definitely enjoying your website. You definitely have some great insight and great stories. Bosch Dishwasher Repair in Santa Barbara

    ReplyDelete
  33. When your website or blog goes live for the first time, it is exciting. That is until you realize no one but you and your. We Specialize in Wolf Cooktop Repair

    ReplyDelete
  34. Thank you because you have been willing to share information with us. we will always appreciate all you have done here because I know you are very concerned with our. Sub-Zero Integrated Refrigeration Repair

    ReplyDelete
  35. Many areas are supplied with hard water meaning that your domestic water will contain minerals, iron and other impurities. water softeners

    ReplyDelete
  36. Ask the electronic retailer to give complementary goods which are required in connection to the appliance you have just purchased. For example, you need a voltage stabilizer for ac, special utensils for microwave etc.Refrigerator Repair in San Diego

    ReplyDelete
  37. When your website or blog goes live for the first time, it is exciting. That is until you realize no one but you and your. Residential Appliance Repair

    ReplyDelete
  38. Thank you because you have been willing to share information with us. we will always appreciate all you have done here because I know you are very concerned with our. Fort Lauderdale, FL

    ReplyDelete
  39. I am looking for and I love to post a comment that "The content of your post is awesome" Great work! Air Conditioning Repair in Beverly Hills

    ReplyDelete
  40. I like your post. It is good to see you verbalize from the heart and clarity on this important subject can be easily observed... Oceanside appliance repair is a service

    ReplyDelete
  41. Thanks for sharing the post.. parents are worlds best person in each lives of individual..they need or must succeed to sustain needs of the family. freezer repair

    ReplyDelete
  42. When your website or blog goes live for the first time, it is exciting. That is until you realize no one but you and your. Sub zero refrigerator repair

    ReplyDelete
  43. If you are looking for more information about flat rate locksmith Las Vegas check that right away. Ice Maker Repair in Sacramento

    ReplyDelete
  44. I am definitely enjoying your website. You definitely have some great insight and great stories. FREEZER REPAIR IN SANTA MONICA

    ReplyDelete
  45. When your website or blog goes live for the first time, it is exciting. That is until you realize no one but you and your. OVEN REPAIR IN CAMARILLO

    ReplyDelete
  46. Perhaps the greatest purpose of concern in this way is the approaching risk because of the rising scene temperatures (Worldwide warming!!). Airconditioning

    ReplyDelete
  47. This is such a great resource that you are providing and you give it away for free. I love seeing blog that understand the value of providing a quality resource for free. granite countertops

    ReplyDelete
  48. Television black out is an example of a major appliance problem, the malfunction is not really evident; the problem would be either in the control device or in the mechanical device.Viking , Wolf, Dacor Stove & Range Repair in SAN MARINO

    ReplyDelete
  49. I am impressed. I don't think Ive met anyone who knows as much about this subject as you do. You are truly well informed and very intelligent. You wrote something that people could understand and made the subject intriguing for everyone. Really, great blog you have got here. OR-marketing

    ReplyDelete
  50. Three-star guesthouse that provides accommodation, Nest and Rest Guest House, Bed & Breakfast in Springs with Events, Conference and Wedding facilities, Lodge accommodation in springs Gauteng. Free Wifi, Swimming Pool and our friendly Staff in a Quiet environment. accommodation and lodge near springs


    Nest and Rest Lodge is a Three-star guesthouse that provides accommodation and small conference facilities. Located within the prime quiet area in springs. Exclusive Lodge, Johannesburg. Best Accommodation in Gauteng South Africa. Enjoy Friendly Staff at a reserve and quite Guesthouse.

    ReplyDelete
  51. I am impressed. I don't think Ive met anyone who knows as much about this subject as you do. You are truly well informed and very intelligent. You wrote something that people could understand and made the subject intriguing for everyone. Really, great blog you have got here. Air Conditioning Repair in Los Angeles

    ReplyDelete
  52. When your website or blog goes live for the first time, it is exciting. That is until you realize no one but you and your. GE, KitchenAid, Dacor, Viking, Wolf, KitchenAid, Ovens Repair in Los Angeles

    ReplyDelete
  53. I believe that will be the first question appear in your mind, when you feel like there is something wrong with your AC. Air conditioning repair is not something really easy to handle. air conditioning repair

    ReplyDelete
  54. On the off chance that an air conditioning channel is left filthy, after some time, it can prompt higher vitality expenses and short Airco Limburg

    ReplyDelete
  55. I needed to go indicate it to my companion and he ejoyed it too!
    Air Duct Cleaning

    ReplyDelete
  56. You make so many great points here that I read your article a couple of times. Your views are in accordance with my own for the most part. This is great content for your readers. Split System Air Conditioning Service Campbelltown

    ReplyDelete
  57. The most ideal way and most significant thing when purchasing focal air conditioning gear is to have it introduced by a certified contractual worker.
    ac air conditioning

    ReplyDelete
  58. I recently came across your blog and have been reading along. I thought I would leave my first comment. I don’t know what to say except that I have enjoyed reading. cheap instagram followers

    ReplyDelete
  59. I’m often to blogging and i really respect your content. The article has actually peaks my interest. I’m going to bookmark your web site and maintain checking for brand spanking new information. ac cuci

    ReplyDelete
  60. This particular is usually apparently essential and moreover outstanding truth along with for sure fair-minded and moreover admittedly useful My business is looking to find in advance designed for this specific useful stuffs… ล้างแอร์

    ReplyDelete
  61. Really I enjoy your site with effective and useful information. It is included very nice post with a lot of our resources.thanks for share. i enjoy this post. ล้างแอร์

    ReplyDelete
  62. I think this is an informative post and it is very useful and knowledgeable. therefore, I would like to thank you for the efforts you have made in writing this article. appliance repair milton

    ReplyDelete
  63. This particular is usually apparently essential and moreover outstanding truth along with for sure fair-minded and moreover admittedly useful My business is looking to find in advance designed for this specific useful stuffs… 大阪のエアコンクリーニングならPTS-FCハウスクリーニングにお任せ。

    ReplyDelete
  64. I am impressed. I don't think Ive met anyone who knows as much about this subject as you do. You are truly well informed and very intelligent. You wrote something that people could understand and made the subject intriguing for everyone. Really, great blog you have got here. Air Conditioner Installation Toronto

    ReplyDelete
  65. I must say, I thought this was a pretty interesting read when it comes to this topic. Liked the material. . . . . Warmtepompen

    ReplyDelete
  66. I am impressed. I don't think Ive met anyone who knows as much about this subject as you do. You are truly well informed and very intelligent. You wrote something that people could understand and made the subject intriguing for everyone. Really, great blog you have got here. Heating in Oshawa

    ReplyDelete
  67. Before trying to carry out air conditioner repair in your home or office, there are certain aspects of air conditioning systems you should know about. When their air conditioning system breaks down or develops a fault, many people try to fix it themselves without fully understanding the concepts involved. air conditioner repair Calgary

    ReplyDelete
  68. hi was just seeing if you minded a comment. i like your website and the thme you picked is super. I will be back. buy instagram likes uk instant

    ReplyDelete
  69. Rapidly this kind of internet site can easily definitely recognition among virtually all blogging and site-building and also site-building individuals, because careful content or simply opinions. ac repair near me

    ReplyDelete
  70. When choosing the proper unit for air conditioner installation, there are a few things to consider. You'll want something that not only fits in your budget, but that will be durable, long-lasting, energy efficient, and come with the features that you desire. Air Conditioner Installation Toronto

    ReplyDelete
  71. When choosing the proper unit for air conditioner installation, there are a few things to consider. You'll want something that not only fits in your budget, but that will be durable, long-lasting, energy efficient, and come with the features that you desire. Air Conditioner Installation Toronto

    ReplyDelete
  72. Really I enjoy your site with effective and useful information. It is included very nice post with a lot of our resources.thanks for share. i enjoy this post. エアコンクリーニング 大阪

    ReplyDelete
  73. This additionally points out for the issue that you need to take great consideration of the air conditioner and attempt occasional upkeep, with the goal that your machine keeps on working in the best condition for quite a while.air conditioning installation perth

    ReplyDelete
  74. You know your projects stand out of the herd. There is something special about them. It seems to me all of them are really brilliant! rackrack liquid cooling

    ReplyDelete
  75. You have shared a very nice post with us. samsung refrigerator repair dubaiKeep it up and keep posting another information and share with us. refrigerator repair dubai international city.The information you have posted is very useful. The sites you have referred was good

    ReplyDelete
  76. Air conditioners gives you harmony during sweltering summer days click here to read customer reviews.

    ReplyDelete
  77. We have the best Ac technician teams for repair and maintenance. Our engineers can be solve all kinds of issues regarding cooling, draining, dirty filter and many others. If you want our ac repair service then you contact us.
    Ac repair Dubai international city
    Ac repair Dubai Satwa

    ReplyDelete
  78. This is such a great resource that you are providing and you give it away for free. I love seeing blog that understand the value of providing a quality resource for free. Summer solution

    ReplyDelete