Cleaning the AC interior coil, AC unit still attached to TM.

[rickst29]

Our A/C performance seems to be "ruined" from a trip to a horribly dusty place last year, when a lot of dust got INSIDE the trailer under high winds and heat. The evaporator coil was filthy (that's the inside one, a little hard to get at). The "filters" provided on the Coleman are IMO a bad joke, and appear incapable of filtering dust. (They're just thin bits of foam, and the foam isn't tight at all.)

So it looks like I was supposed to remove the entire top unit from the roof of the TM (yeah, that's awkward and heavy to do), set it on saw horses so that all the degreaser and dirty washing water goes into some kind of pan or drain. THEN put it back on the TM, being careful to re-do all the seals, and etc.

But, being a very lazy person, I considered this carefully. Instead, after removing the underside unit and heater coil, I left all the rest still attached to the top of the TM. I put a big garbage can inside to catch the gallons of "drippings", and everything seems to have gone fine. I have vinyl flooring, though-- if you have carpet, you'll need to be much more careful than I was. But for me, with vinyl flooring to easily towel up the misses, just the garbage can did really well.
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Other things I noticed:

(1) someone at TM sure wanted to "save money" by skimping on aluminum tape, there appear to be seams where small air gaps could be present between the outside and interior air path on the fan side of the coil. I think that ANY chance to suck hot outside air into the interior fan is a bad thing, so I'm gonna tape EVERY seam when I put it back together tomorrow (it's drying tonight and most of tomorrow). If there were gaps, they were kinda small. But why not tape everything?

(2) the "top plate" plate, which is screwed down above this coil, doesn't have close contact with the fins. There's definitely an air gap, and I don't want that-- I'd really rather have slightly crushed fins than the blow-by which happens now. I might add some fill-in material on the underside of the top plate before I put it back on -- I think the air needs to go THROUGH the fins, not AROUND them!

[rickst29]

#2 "I noticed" at the end of my first post isn't right-- the insulation on that "top plate" does make a pretty good seal against the top of the coil.

Here's additional notes:

(a) although I waited a full day before turning it on, there was a LOT of "rinse" water left in the part of the unit which I didn't expose (after the evaporator and into the fan). If you do this like I did, without taking the motor housing off, expect another half gallon of spray from the fan when you turn it on-- and be SURE to have the control and power circuitry protected, maybe turn it on with plastic sheeting in place to protect the wiring from water.

I turned it on AFTER attaching the control panel back to the roof and taping the output tube back together; I was merely lucky that a nasty short circuit didn't happen from all that "hidden" rinse water. And keep a big bucket (or garbage can) underneath to catch it all. My blower moter was unaffected, but I may have been lucky there too-- I have no idea if the blower/fan motor (there's only one motor used for both jobs) has decent water resistance or not, I never exposed the motor.

(b) that heater coil has a large "power unit" which takes about 5 square inches of area from a very small section of the air intake. As others have noticed from time to time, there's also a risk of IMPORTANT wires coming loose and getting burned against it. And finally, in order to make good "contact" with the airflow, it has fins which further mess up the airflow entering the evaporator coil. And so, overall, I think that this little heater unit is a very bad idea. If you want to use a bit of electric heat, instead of turning on the big propane unit, just set a couple of cheapo WalMart "spot" heaters on counters, plug 'em into your regular 120v outlets. And besides, you can aim them where you need them, instead of settling for the roof unit blowing down the middle of the hallway.
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Filter-wise, I'm going to try some MERV-9 polyester media, packed into the intake areas above the current structure (I'll be cutting out the current plastic ribs and making a couple of small metal forms to hold the media in place.) The material I bought is 1" thick. This has a lot more resistance than fancy thin media with lots of pleats would have (i.e., high end "Filtrete" and similar pleated media), but it can be cut to fit into the funny-shaped areas much more easily, without leaving gaps. Creating new frames for pleated media to fit those odd shaped areas would be kinda slow, and not interesting or fun to do at all, I think.

I'll post my results for the "thick media" filter (how much airflow reduction, how much crud gets caught by the MERV-9 media, effects on noise level, if any) next summer, when we hit the road again.

[Wavery]

I hope that you read the label on whatever "De-greaser" that you used.

De-greasers are normally not used on aluminum and the fins on those coils are very fragile.

They make a chemical exclusively for cleaning AC evaporator coils. It's water soluble, orderless, harmless and does an amazing job.

[rickst29]

Originally Posted by harveyrv

I hope that you read the label on whatever "De-greaser" that you used.

Yeah, I should have said this in this first post: I used the same "awesome" yellow liquid spray from the dollar store that many of us use on the TM exterior. Worked great, it's friendly to aluminum and plastic and even TM interior "wallpaper".

And my HVAC guy actually recommended it by name for the house A/C, too!

[Bill]

Rickst -

Thanks for coming back with the update. Too many people post about a problem, work with the advice that is offered - but never come back to tell us the final solution. Believe me - the people on the board care! Documenting solutions to problems is one purpose of this board.

Bill

[Wavery]

There are a number of chemicals on the market for AC coils. This is the one that we use in our apartment building AC coils.
https://hdsupplysolutions.com/webapp...roductId=65978

[rickst29]

dennis asked me for more details, so I'm duplicating my email reply to him here:

"LA's TOTALLY AWESOME" comes in a clear bottle of 20 fl. oz. The label also says "As seen on TV" on the front. On the back it says, "This product is not manufactured by the R.F. Thompson Company or Affiliated with it's 'Awesome' Brand Cleaning Products". The actual mfr is "Awesome Products Inc." of Buena Park, CA.

There are other flavors of this on the shelf, including a larger bottle of "orange" flavored stuff stuff (the bottle itself is blue). But the bigger bottles don't SAY that they should be cut with water-- so I suspect that they're not as concentrated.

There's a big list of dilution instructions on the bottle, e.g. "aircraft" is 10:1, and "kitchen stove" is 5:1 (water to 'totally awesome'. They SAY to use 10:1 water for "air conditioners", but I've only used it straight out of the bottle for MOST of the really nasty things I use it on-- air conditioners (TM and house), asphalt and pine sap stains on TM exterior, wallpaper stains on the TM interior, and asphalt-based roofing compound clean up from roof repair. It's much better to use this on the TM wallpaper than to scrub and scrub with something less strong-- scrubbing causes real damage on that wallpaper, this is totally safe (although I've never had it on there for more than a couple of seconds before gently wiping clean.)

For the home's AC condenser, I make a quick "river-bank" out of duct tape to direct the runoff into a garbage can lid, and each time that fills I dump that into my house's sewer cleanout. It's obviously way too concentrated and "nasty" to allow runoff of this stuff onto the ground or untreated storm sewers, that would be grossly irresponsible.

For anything on the TM exterior or interior, it's just spray on and wipe off. For my model year (2006), it's "awesome" on interior wallpaper stains too -- no damage, no scrubbing needed. And of course, it's just spray on- wipe off to look showroom new on the exterior.

Again, you're looking for "LA's Awesome". Wayne, your product appears to have an advantage in "rinsing not necessary", but I like having just one little bottle around to do everything. Thanks for the link, though, others might prefer the convenience of the one you just pointed at.