garys_2k
join:2004-05-07
Farmington, MI
 ·Future Nine Corpor..
·Vonage
|  ? Cleaning A-Coil
When I moved in I found that my furnace's filter had been only partly covering the air path, so presumably a fair amount of dust made it to the coil. I fixed the filter issue but I do want to check the coil. How do I do that?
The coil's mounted directly on the furnace, in the discharge plenum, with no access plate. I can cut the sheet metal, but where would be best?
I assume that the bottom of the coil (I have an updraft furnace in the basement) is the part most likely to be dirty, as the air flows bottom-to-top. The refrigerant and pan drain exit from the north side of the plenum, the south side has very little clearance to the descending cold air return. Should I try cutting the sheet metal on the side where the refrigerant lines exit? I'm planning on using a dremel wheel to do the cutting. |
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tp0d
yabbazooie
Premium
join:2001-02-13
Carnegie, PA
clubs:
 ·Verizon FIOS
2 edits | What kind of furnace is this.. 80 or 90% efficient? (chimney or plastic pipe?). If it is a 90%, then all the dust/fuzz would stick to the secondary exchange radiator just above the fan. (which has almost the same size fins as a cooling coil). This could be inspected just by removing the fan, no cutting.
Or if you have an 80% furnace, any fuzz would make it to the cooling coil. Removing the coil is the best way to clean an upflow. If you have movement on the copper lines you can do it, but if you dont, an hvac tech would have to disconnect/reconnect.
Odds are, unless the furnace is 10-15yrs old, the coil probably isnt too bad. How clean is the return air duct pre-filter?
good luck
-j
--
if it aint broke, tweak it!!
currently on FiOS (kick aZZ!) |
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garys_2k
join:2004-05-07
Farmington, MI
·Future Nine Corpor..
·Vonage
| The furnace is original with the house, about 22 y.o. so nothing great in the efficiency dept. Galvanized vent pipe leading to the draft box near the top of the furnace, old school stuff (no standing pilot, I guess it was new when that was eliminated).
Removing the coil to get at it sounds like the right way to go about it. I'll have to see how much slack I have, but I think there'd be enough to do it.
So, cut away the entire lower section of the plenum? |
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Tyreman
join:2002-10-08
4 edits | Where the coil refrigerant lines go in and below, and a bit above.
Cut the sheet metal out as neat as possible with left and right snips.
Cut out neat go slow.Watch for any cap tubes if present don't cut them
As you work look inside and observe to see the coil t pee.
Have s cleats to slide on the furnace plenum metal after and plain sheet metal stock to make a coil access slide to cover the opening later.
You have installed the s cleats out so the metal will slide in the cleats.
Imagine picture frame.
You can cut the cleats on a angle so they look neat where they join up at the corners.
If you have a bar folder to make a 90 degree pull on one end do so.
After gaining entrance
You will see in\on the coil a series of candrill type screws to remove I call it the coil T pee...shaped like a T pee.
Its a piece of sheet metal that is can be removed to clean the coil
remove all the screws, look thoroughly
could be about about 8 or so.
Down at the drain pan base, whee the t pee meets they are hard to see at each corner
that allows you in to see, once the sheet metal t pee is removed the underside of the evaporator coil. assuming A style coil.
Just be careful if cap tubes present so no damage is done to them
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Southern Ontario,Canada |
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garys_2k
join:2004-05-07
Farmington, MI | Thanks, the cap tubes are what I'm leery of snagging. I'll have to go VERY carefully.
I didn't realize the TP cover would be removable, that's what I needed to know to even think about getting a brush and vacuum cleaner in there. |
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Tyreman
join:2002-10-08
3 edits | You won't snag them if you go slow and watch what you are doing.
it might not even have traditional cap tubes.
could have orifice or bullet metering.
You will get to see the exact size of coil access slide you need after you get an 8x8 or so access to start out.
After if you want to secure the sheet metal coil access slide at the "pull' end with a metal screw(s) make a careful note and mark a "clear" area, free of tubing so you can install a sms screw or two.
this prevents excess air loss or rattles
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Southern Ontario,Canada |
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tp0d
yabbazooie
Premium
join:2001-02-13
Carnegie, PA
clubs:
·Verizon FIOS
1 edit | forgot to tell you how to open the plenum, doh!
There are slide fittings on the corners of the duct that should come off, or possibly compression fit joints that push together. These will come apart with a little time. Usually the coil is put in after the plenum is set on the furnace, or if you have a better A coil, some come preboxed, and there will be a few 1/4" screws to remove the front panel. If its 22yrs old, thats prolly not the case.
Definitely try to remove the panel with the coil protrusion before cutting. If you do the dremel method, you could cut thru a copper tube inside without knowing, and yer f*cked
-j
--
if it aint broke, tweak it!!
currently on FiOS (kick aZZ!) |
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