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Wednesday, June 14, 2017

It's Hot - How To Care For Your Roof Air Conditioner

The Roof
    This past week has been incredibly hot, especially for Spring in the Northeast. It has been above 90 degrees for the last couple of days and it got me thinking about making sure my A/C unit would keep functioning efficiently far into the future. Since Murphy was an optimist (Murphy's Law - Anything that can go wrong...will. And at the worst possible moment) I figured the time to treat my A/C to some preventive maintenance was sooner rather than later. I kept thinking of a crazy hot day, enjoying the coolness inside the RV and then WHAM! No cool air. Even with all the vents open and fans running, it wouldn't be nearly as pleasant. Livable? Perhaps....but pleasant, not likely. With some very simple steps, you can keep your roof air conditioner working well.

Typical RV Roof Air Conditioner
First off is a good old-fashioned cleaning of the outside unit. Once that's done, I remove the shroud covering the A/C unit itself. It's very easy, usually just a bunch of Philips head screws around the edge. Then gently pull off. Depending on the make and model, you'll see what looks like a radiator from a car, a motor or two, a compressor, a large fan (or two) and some wires and piping.

Make sure the 120V power is off before reaching in to do ANYTHING! Once power is off, make sure all the vents are clear of debris like leaves, dirt, pollen, tree chunks, critter nests, anything at all really. You'd be surprised at how many vents are clogged. That will REALLY decrease the efficiency of your AC.Then get in there with a duster and start cleaning. Be careful. It is easy to bend or damage the fins on the radiator. If they are already damaged you should gently bend them back to straight. The more surface area, the more air that can circulate which equals better cooling. Look at the fan(s). Is there a gunk buildup on the blades? Gently clean with a rag, damp with a mild soap and water solution. Look for anyplace air travels and gently wipe away accumulated dirt and/or debris. If you have a compressed air source, you can use it to blow dirt and debris from between the fins and small spaces within the unit.

Before replacing the shroud, check to make sure the inside is clean. I was AMAZED at how much dirt was caked on the underside. There may be a foam gasket under the shroud as well. Make sure it's in decent shape. If it's falling apart, scrape it off, clean the area where it was stuck on and apply a new one. I used easily obtainable foam insulation tape and matched the curves of the original. It wasn't difficult to match the curves and I get a much better seal now. Once it's nice and clean inside, close it back up, replace the screws and go inside.

The Two Side Covers Are Easily Removed
Once inside, look at your air control unit. If you have a ducted unit, there should be multiple vents across the ceiling. All should be free of dust and debris. I know someone that once found critter nests all throughout his ducting. No wonder there was no cool air. Bet the critters were comfortable on hot days though! On the simplest systems, directly below that outside roof-mounted unit is an air controller. Typically it has two filters under two separate covers and a couple of directable vents at the front and back. If you remove the filter covers, you will see a couple of replaceable or cleanable filters. Check them, clean if possible, replace if needed, then look up into the holes they were in. Make sure there is no dust nor debris in there. Be careful, there may be several sharp edges inside. While they are open, I usually check to make sure the four bolts that snug down the roof unit are indeed ... umm ... snug. Not too tight. Check the manufacturer's specs for the correct torque. Move on to the front and rear vents. Clean out whatever doesn't belong. Be gentle -- it's usually only lightweight plastic. Reassemble the filters and covers.

That's it. Sounds like a lot of work, but it really isn't. Once my roof unit was clean, I noticed a significantly increased air flow and a drop of 2 extra degrees in temperature. It may have been my imagination, but the compressor didn't seem to be working quite as hard as before. It definitely feels cooler. If I'm lucky, I may very well have increased the useful life of one very expensive piece of RV hardware AND made myself a bit more comfortable in the process. Win-Win!

Be Seeing You...Down The Road,

Rich "The Wanderman"
www.thewanderman.com

15 comments:

  1. For the fin area, I use foaming AC coil cleaner from Lowes. Spray it on, let it foam, then gently rinse off. The foam pulls all the dirt out from deep inside the fins.

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    Replies
    1. Mike,
      That sounds like a good idea, I will check into it. Thanks for the tip!

      Rich "The Wanderman"

      Delete
  2. While you are up on the roof, with the cover removed, check the fan motor, for oil cups or ports. Many motors no longer have them, but if yours' do, a few drops of oil, in each one (don't overdo it) will drastically increase the life expectancy of the fan motor.
    Also, check and clean, the condensate drain, if it gets plugged you, you will have, "running water" inside the rig, but NOT where you want it running.
    Lastly, although not necessarily a DIY project, for Joe Average, consider having a "hard start kit", installed on each A/C. They can greatly extend the life of your compressor, especially given the voltage situations in may campgrounds. I install them routinely, anytime I service an RV A/C, for the first time.
    Butch

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    Replies
    1. Anonymous,
      All GREAT Tips. I do not have any oil ports on mine, but have already installed a Hard Start Capacitor to ease the motor start burden.

      Rich "The Wanderman"

      Delete
    2. Would a surge protector serve the same function?

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    3. Roobin,
      NO! A surge protector protects the wiring and elecyronics from spikes of high current/amperage. A Hard start capacitor charges up and sends a higher amount to "start" the motor. This way your require less current to get it going. Easier on the circuits and parts.

      Rich "The Wanderman"

      Delete
    4. While shopping for the hard start kit I see they are made for various tonnage of units. Is a typical 13,500 BTU RV AC unit in the 1 ton range?

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    5. One more question. My AC units are heat pumps — does your advice to install a hard start kit still apply?

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    6. George,
      Anything that uses a high current draw device like a motor or a compressor can benefit from a hard start capacitor. You should look at your manufacturers recommendations to be sure they don't have anything special already inside that may not like the extra current though.

      Rich "The Wanderman"

      Delete
  3. Another baisc chore....turn on the unit occasionally, even in the winter months . Let it run 5-10 minutes. This helps prevent the fan from locking up due to the shaft getting stuck from rust, etc. Othwise, you'll be making a trip to the rooftop to remove the cover and gently turn the shaft with a pair of pliers to breaker it loose.

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    Replies
    1. Mike,
      Sounds like you've had that happen. It's ALWAYS a good idea to have rotating and reciprocating parts that touch move occasionally. It will keep things in good repair and properly lubricated. Running the compressor for a few minutes will accomplish the same thing for the internal components and lubricants within the refrigerant. Sometimes it takes a while for the compressor to kick on in RV air conditioners. You can usually tell..the sound changes quite a bit.

      Rich "The Wanderman"

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  4. No, gotta physically run the motor for a bit. I found out the hard way.

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    Replies
    1. Mike,
      Live and learn... I find that out time after time. Costly, but I know I'll only make those mistakes once. i hope!

      Rich "The Wanderman"

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  5. No cost, just the hassle going up, removing the cover, applying the pliers to break it loose so it spins. Gettin' too old for journeys to the roof!

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    Replies
    1. Mike,
      It's 91 degrees here today. not much fun going up on the roof for any kind of maintenance! Hydrate!

      Rich "The Wanderman"

      Delete

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