Disassemble the B vent and the coil will slide out if there’s enough lineset

 

Sorry, missed your reply. Is the coil just sitting in there? I'm a retired pipefitter, but it makes me a little nervous to move that old tubing that much. Is that something that's done a lot, standard practice? I like that idea, except that it's in my attic and I wanted to wash it off putting the water down to condensate drain. Still, at least your way I could dry clean it. Thanks for the help!!

 

Ok, I think I get it now. Please correct me if I'm wrong. I need to remove the triangle shaped piece of sheetmetal from the side of the evap coil, right? To get it out I'll also need to remove the left side access panel and to do that I'll need to cut around the drains and refrigerant lines. I saw in a video that the top of the triangle piece will fall in between the two sides of the coil and lay flat. Then you can pull it out horizontal once the exhaust vent and other sheetmetal are out of the way. What a pain.

 

Unrelated to your original post but as your user name implies of your furnace is in California then there were issues with the NOX inserts in those rheem/Ruud criterion furnaces causing heat exchanger failures. Just FYI… the original ones had to be replaced with a different version. Send pics of the burners pointed towards the heat exchanger and I can maybe tell if yours was retrofitted or not.

 

Yikes, I had no idea. I'll take you up on your offer and send those photos, thanks for the tip.

 

Cleaning the underside of the indoor coil is absolutely not part of normal maintenance - leave it alone unless you confirm it is actually dirty.

The filter is supposed to keep the blower and indoor coil clean.
If the air is properly filtered, the coil will stay clean - return leakage, not changing filters, leaking around frame can cause blower and coil to get dirty.

If you have a inspection camera, you can remove the high limit in the furnace, stick the camera scope in pointing up and inspect the coil.

 

Thanks for that advice. When I purchased the home it was almost 20 years old. The filter was filthy, but I'm with you, "don't fix it if it ain't broke"
I'd be suprised if air didnt leak around the filter, it uses those thin filters and they dont fit real tight, plus I have a very think coated Golden Retriever. I do have an inspection camera but it's 2 hours away at my desert home. I'll be out there next week and will bring it back with me. Thanks again.

 

Check the blower assembly for dirt - if it's filthy the coil likely is too.

 

Yes, I can do that tomorrow. Thanks

 

Most MFG's of A coils leave a panel on one of the ends of the coil for removal. to clean the inside of the coil, which is the most important part of coil cleaning. Try the other end away from the exhaust pipe.
Your coil needs a through cleaning, the corrosion is a bad sign that the unit may not be working the best it can. Usually the side to access is the one opposite the little tubes.

I can not express how careful you need to be when doing this. The little pipes can come unsoldered easily. This is high pressure soldering not water pipe. Old pipes can be a problem to seal again.

The installer certainly did you no favors.

 

Most MFG's of A coils leave a panel on one of the ends of the coil for removal. to clean the inside of the coil, which is the most important part of coil cleaning. Try the other end away from the exhaust pipe.
Your coil needs a through cleaning, the corrosion is a bad sign that the unit may not be working the best it can. Usually the side to access is the one opposite the little tubes.

I can not express how careful you need to be when doing this. The little pipes can come unsoldered easily. This is high pressure soldering not water pipe. Old pipes can be a problem to seal again.

The installer certainly did you no favors.

The rust in the pictures is absolutely normal because the tube sheets are made from regular steel and are exposed to condensate.
That rust means nothing about the condition of the important parts of the coil - the integrity of the tubing and aluminum fins. Every older coil made with the same materials that has been used enough will look like that.

That looks like a cased coil so the other side is probably not accessible without ruining the coil case.

 

It should unless the blower has been cleaned, since you have a inspection camera, you might as well check the coil from the high limit opening.

 

Yes, but since my camera is 2 hours away, and I have this week off, I thought I could check it out and clean the coil if needed while I'm home. Do you know how big the hole for the switch is on my unit? Would a light and a small inspection mirror maybe work?

 

It's pretty small on most, a mirror would not work.

You should absolutely not try to clean the coil unless you're sure it is dirty - the risks trying to pull it hoping there's enough slack in the refrigerant line are too great.

It probably doesn't need cleaning.

 

Is the air flow through the registers okay and strong when in heating mode (furnace on, A/C off)? If so then the A/C evaporator is not in too bad shape, cleanliness wise.

You can vacuum out the evaporator unit a little using a home made(?) nozzle with a sharp 90 degree angle at the very end so it sucks out of the evaporator fins as opposed to parallel past st the evaporator fins.

If you do a heavy duty cleaning, most of the water or fluid and dirt and dust will miss the condensate tray and fall into the furnace heat exchanger and down to the bottom of the furnace at floor level. Might not be too bad a result provided you sponge up or mop up all the water and let everything dry out and vacuum up loose dirt inside before turning the system back on. Don't want the blower motor to run wet.

Do not touch metal edges with your hands. These edges can cause severe cuts even though they are not all that sharp.

What is on the opposite side of the furnace main duct where the evaporator coil is sitting? From which vantage point you would (with Superman's X-ray vision) see the opposite also triangular shaped side of the evaporator coil. It might be easier to cut an access opening there instead of work around the pipework and exhaust vent pipe on the side we are viewing.

Do not actually pull the evaporator coil unit out.

I would advise against cutting the triangular piece. Removal of that piece might cause the evaporator unit to change shape so that condensate (water) falls inside the furnace instead of being caught and routed out the white drain lines.

On my own system I cut out access panels for the main air duct (vaguely looks like yours) with U shaped slots instead of round holes for the pipes so the panels could be slipped on and off as needed and the evaporator could stay in place during cleaning. (The cover panels had to be made of new sheet metal because the metal cut from the existing duct was too small to re-cover the opening.)

 

I put the camera in for an inspection. I can see that there is some gunk on the fins, but I don't think it's too bad. Kind of hard to tell. I captured some stills from the video and posted them here. The clearest shots show very clean fins but some of the not so great photos of other areas don't look as clean. As far as removing the triangular piece from the other side, that would require cutting the enclosure sheetmetal and hoping that the triangle piece is removable. Also, it's not an easy area to get to, but doable. If I knew for certain that the triangle was removable and that the evap really needed to be cleaned, I would go that route and make a removable access panel. If you want to take a look at the photos and give me your impression, I would sure appreciate it. At least now I know at a minimum, there are open unobstructed paths for the air to flow through the evap. so I don't think cleaning it is urgent. I'm going to review the video again to see if I can tell if the back triangle is removable. I'll post the video and add a link here if I can figure it out ;-). Thanks everyone!!

 

Your coil doesn't need cleaning.

Though if you want to remove minor dust/dirt buildup - during the cooling season, you can spray some no rinse coil cleaner and the condensate will wash it off.

 

Thanks, that's what I wanted to hear!! Will spraying it from the back side work? That would be a lot easier 😉

 

Yah but I think you would need to spray more to get enough into the other side.
Do it only when the a/c is in use and producing condensate.