Getting inside plenum to clean A-coil


Old 11-26-18, 11:56 AM
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Getting inside plenum to clean A-coil

I'm trying to get in to clean the undersides of the coil. This will require getting into this panel. Cutting another opening looks difficult, especially to do it neatly and to cut the right size and shape and create an acceptable cover. This sheet metal looks like a pretty good job that I'd rather not cut into.

I'm wondering if it would be possible to remove the whole panel that appears in the photos to access the A-coil from the end. There are red marks to show the sheet metal screws that screw into the front and sides. I can get all the screws out, and the cleat slides off and up. But the metal panel is still tight even with these fasteners removed. Can I remove this and replace it without messing up something? Is this panel made to be removable?
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Old 11-26-18, 04:47 PM
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Looks like snap lock joints. Kind of a pain, but doable, see attachment. Is the side shown that you want to remove the opposite side of where the line set and drain are?

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Old 11-26-18, 04:55 PM
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Yes. This is the side opposite the drain and lines.
Old 11-26-18, 05:11 PM
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Im not an hvac guy, but I would want to cut it open and make an access panel that could be easily removed year after year. It looks like a lot of old school stuff does... not put together with maintanence in mind.
Old 11-26-18, 05:30 PM
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They should have left an access panel for service but if not You can cut a square access panel as large as you need for access and then cover it with a piece on sheet metal panning which is nothing more than a flat piece of sheet metal which you can usually get at the box stores and cut to the size you need and be able to remove for future maintenance.

I would cut the drain side if possible. That's generally the side you're going to want to access if any problems occur so if you make an access now you will be able to get to it later.

I've had to do it in the past where no access was left and it works fine, you can do it yourself and cheap.

Hope this helps a little.
Old 11-26-18, 07:25 PM
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It originally looked like snap lock edges but expanding the photo makes me think the panel might be flanged into s-cleat with screws holding it. I've done many like that myself. If your goal is to clean the underside of the A-coil I would go in from the side shown as you won't be blocked by the copper feed tubes when removing the coil's end plate. Whether it be a brush or a vacuum you use to clean make sure you don't drop it into the heat exchanger. I often tie a string to what ever I'm using in case it falls.
Old 11-28-18, 10:06 AM
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How do you know the coil needs to be cleaned?

The underside has to be visually inspected, perhaps with a snake camera through a limit opening in the furnace.

Or the static pressure drop across it needs to be checked.

It can't really be done well in place unless there's a decent gap between the furnace and coil, in your case it's right on top. Requires a contractor to pump down the refrigerant, disconnect the lines and pull the coil. A very expensive job.

Coil cleaning is not part of normal maintenance, the filter is supposed to keep the blower, secondary heat exchanger and coil clean.

If the blower assembly is clean, the secondary and cooling coil probably are too.
Old 11-28-18, 07:48 PM
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Post #7 brings up some good points on whether or not you need to clean the coil and that it is not normal maintenance. If though, you asked your original question as you know it is clogged, the cleaning might not be as bad as described. Once those 8 screws are out and the panel is off you will be looking at the back of the A-coil. There you will see a triangular coil end plate that can be removed, usually with a 5/16 nut driver. Once off, any debris can be vacuumed off the coil's bottom. You might also have room to spray interior coil cleaner down from the top. Be careful not to drop stuff down in the HX. I've used cardboard to prevent drops when I didn't have a vacuum cleaner with a brush attachment. -I'd go out back and grab a coil for photos of the end plate, but it's to cold out-.

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