Howdy, Anyone know if it is possible to bleed an oil line thru the small hole on the air filter housing? Thanks

One of the things I learned when resurrecting an 80K BTU Trane XL90 92.5% efficient dual stage furnace (model TUX080R942v2) with a inducer motor with bad bearings is that there is a known design flaw in the 2006 and earlier builds of this furnace in the plastic transition fitting that goes between the cold end condensate sump of the heat exchanger and the inducer blower assembly. I found it had cracked and the ensuing condensate leak had rusted/corroded away part of the inducer motor mounting bracket which is screwed onto this transition fitting. (See this thread if your are interested in how to replace the inducer motor bearings: [url]https://www.doityourself.com/forum/gas-oil-home-heating-furnaces/631555-trane-xl90-xr90-furnace-blower-motor-inducer-more-info.html[/url]) [b]What researching the problem turned up:[/b] When researching the issue I discovered that Trane/American Standard published a service bulletin about this which states that during the 2006 model year they made an improvement to the design of this fitting to prevent the cracking that caused the previous version of the fitting to have condensate leaks. In that bulletin, they state that the improved version of the fitting won't work for the older furnaces. That turns out NOT to be true. All that is needed to make this new fitting work is to do some slight modifications to the sheetmetal inducer mounting bracket. The offset bent area below the inducer opening needs to be modified and rebent to accommodate the lowered location for the transition fitting's bracket mounting holes. Then two new holes are then drilled in it for the screws. The rest of the fitting is EXACTLY the same, and fits the heat exchanger sump flange and the inducer assembly fits onto the transition fitting's flange nicely too. I'll go into some detail into the modifications that will be needed to the existing inducer sheetmetal mounting bracket below. Or, for those not wanting to mess with these modifications, there is a revised inducer bracket that can be purchased that has both the original and the lower mounting screw holes drilled into it. The original inducer motor mount bracket, part number MNT1266, is no longer available This revised part number is MNT2458. The flawed original transition fitting is part number is RCT00084, and the improved fitting is part number is RCT00851. Here's a link to a PDF of that somewhat erroneous service bulletin: [url]https://pimmedia.winsupplyinc.com/pim/INTA/112017/AMERICAN-STANDARD-AIR_RCT00084_ASTRCT00084_INTA.pdf[/url] [b]What I found on the furnace and how I dealt with it:[/b] After I removed the inducer assembly from the furnace to repair it, I discovered some serious rust and corrosion to the sheetmetal inducer motor mounting bracket. In fact, the part of the bracket that screws onto the bottom of this transition fitting was completely eaten away by this. Once I had the transition fitting off the furnace, I discovered the cause of the cracking -- for some reason, the engineers at Trane had designed the lower screw receptacles in that fitting to be located INSIDE the wet condensate sump area, and the plastic screw receptacles were weak due to a poor design, and were subject to cracking over time. Once they cracked, the zinc coated screw would rust and expand due to the rust, and would further crack the receptacles, and then would cause further cracking in the rest of the transition fitting, which caused acidic corrosive condensate leaks. These leaks would eat away at the sheet metal inside the furnace, and could drip onto the furnace control board located in the lower blower chamber of the furnace ruining the control board. I was somewhat lucky with this furnace, because the condensate didn't drip onto and ruin the control board as has happened to some folks. Instead it ran down the sheetmetal control board mounting bracket behind the board instead. Here are some pictures of the transition fitting I removed showing the issues: [img]https://cimg7.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/inked20211018_193045_li_e2dd4459288801415e2a8b406ab2738436fac0ee.jpg[/img] [img]https://cimg8.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/20211018_193126_annotated_a7289a7f3b6e45f2922f1caeac9a32303cf67649.jpg[/img] [img]https://cimg1.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/20211018_193037_fff8c5c28931cf74f35c359ecacabebcbdaee6fe.jpg[/img] [img]https://cimg5.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/20211018_193148_b910864227f15c4fc787b62d147e019b89fa3141.jpg[/img] [img]https://cimg7.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/20211018_193205_06d5d6e9aaaac68c72164caed3053069ca12ac88.jpg[/img] [b]So I ordered the improved transition fitting because I thought I could make it work:[/b] Once I had the improved RCT00185 transition fitting in hand, I did a careful inspection of it against the original transition fitting (RCT00084), and verified what I thought I had seen in the pictures -- that everything is the same except for the location of the lower two mounting screw receptacles. I did a dry fit of the new fitting onto the heat exchanger flange, and also onto the intake port on the inducer assembly -- both fit perfectly and were located in the same position as the original flawed RCT00084 fitting. Below are pictures of the improved transition fitting: [img]https://cimg3.ibsrv.net/gimg/www.doityourselft.com-vbulletin/409x445/trane_rct00851_dd3187a9016bfae0d16c28535a3375f083dc72b1.jpg[/img] [i]All that changed is that the location of the lower mounting holes has been lowered.[/i] [img]https://cimg4.ibsrv.net/gimg/www.doityourselft.com-vbulletin/334x255/duct_connector_rct00851_05153851_a82e3adcd0617e80ac5192eabbc9d2565c95f79a.jpg[/img] [i]In this rear view you can see the better reinforcement for the lower screw receptacles, and that they are now located below and outside the "wet" condensate area, so even if they crack, there won't be a condensate leak...[/i] [b]I decided to inspect inside the heat exchanger condensate sump:[/b] Before I mounted the replacement transition fitting, I got my video inspection scope out and looked all around inside the condensate sump. Luckily I didn't find any cracks. I did find that the upper left corner screw receptacle had cracked, and removed that screw (which was badly rusted and corroded), and filled the area with HVAC high temp silicone sealant, and bedded a stainless steel replacement screw in it's place with the same sealant. Since it is in the upper corner of the sump area, there shouldn't be any condensate leaks, and the silicone sealant will prevent any condensate vapor or combustion gasses from getting through there. This likely happened because someone over-tightened the screw which caused the receptacle to crack. [b]Mounting the new transition fitting:[/b] I used the same silicone sealant and [i]slightly[/i] overfilled the groove in the back of the transition fitting that fits onto the heat exchanger sump flange. By slightly overfilling it, I insured that it would squish out a bit on both sides and would form a good permanent seal. I filled the receptacles for the mounting screws with the same sealant to help insure that if they cracked there wouldn't be a condensate leak, and I used some more of the sealant to bed the screws that fastened the plastic transition fitting onto the heat exchanger. I also substituted some 5/8 inch #10 stainless panhead sheetmetal screws instead of the zinc plated 5/8 inch #10 screws supplied with the new transition fitting, to slow down the rust should the receptacle in the heat exchanger crack in the future. The silicone used to fill and bed these screws should also help prevent this.... -A word of caution -- make sure you [i][b]don't over-tighten[/b][/i] the screws -- get them good and snug, but stop there. If you over tighten them you are likely to induce cracking in the plastic. My understanding is that the plastic condensate sump that's attached to the cool end of the heat exchanger is not replaceable -- the entire heat exchanger has to be replaced if it cracks. [b]Sheetmetal inducer mounting bracket repair:[/b] Unfortunately I didn't take a picture of my damaged sheetmetal inducer mounting bracket, but below is a picture of a non-damaged one and I have marked the portion of it that had completely corroded away. [img]https://cimg7.ibsrv.net/gimg/www.doityourselft.com-vbulletin/750x587/annotated_original_inducer_mounting_plate_1_97a2025542a18715698fba4fd4edf01ed8d57efe.jpg[/img] In my situation, since that area of the bracket was gone, I fabricated a z-metal shaped sheetmetal piece that had about a 1/8th inch step in it out of a piece of galvanized roofing step flashing I had on hand. I cut out a rectangle the size that was needed, and then used a vice and bent a 90 degree bend in the middle of it, and then re positioned the part in the vise so about 1/8th inch was showing after that bend and used a screwdriver and a hammer to bend it over again to form the 1/8th inch step needed. I then marked and drilled holes for the screws that mount to the bottom of the new transition fitting, and screwed the fabricated piece onto that location on the transition fitting. After cleaning up the rust and cutting away the remaining rotten parts of it, I repainted the inducer mounting bracket. I then reattached it to the transition fitting using the remaining two upper mounting screw holes. This mounted the inducer mounting bracket [i][b]in front[/b][/i] of the newly fabricated piece. The 1/8th inch step in the newly fabricated piece plus the thickness of that metal matched the original depth of the inducer mounting bracket's missing step. I then drilled two 1/8th inch holes through both the existing bracket and through the fabricated piece about 1/2 inch below the bottom of the transition fitting and used two 1/8th inch steel pop rivets to connect the two together. I used pop rivets because there isn't room for the height of screw heads between the inducer assembly and the inducer bracket, and the small pop rivet heads are almost flush with the sheetmetal. If your inducer bracket is damaged like mine was, you could do this too and save the cost of a replacement bracket. [b]How to modify a bracket that hasn't been damaged to fit the improved transition fitting:[/b] You'll need to make two vertical cuts extending below where the existing lower mounting holes are, and do some re-bending of that portion of the bracket to allow for the new lower location of the screws. It is important to get the depth of the "step" bent into the sheet metal correct as it will affect the fit of the inducer assembly onto the transition fitting. See the annotated picture below: [img]https://cimg8.ibsrv.net/gimg/www.doityourselft.com-vbulletin/750x587/annotated_original_inducer_mounting_plate_2_0e23c64d3f4cde59fb82e8073f8e8b064d87e974.jpg[/img] Here is a picture of the revised inducer mounting bracket that has both sets of lower holes already drilled in it. Again, the part number for this inducer mounting bracket is MNT2458: [img]https://cimg5.ibsrv.net/gimg/www.doityourselft.com-vbulletin/1135x769/mnt2458_48d8b8c627d339adafd8b5cc960ad47e2f2c6e86.jpg[/img] I hope this helps folks dealing with this flawed transition fitting. I don't recommend replacing a bad one with the same flawed fitting as it will likely crack and leak again.