Hi. I have a 6" oval duct running in a joist bay that I need to split in two and run oval ducts across the joists to supply two vents in the basement suspended ceiling. I searched online and have not found an "oval tee". I am thinking of attaching an oval start collar on top of a piece of oval pipe to make myself a tee. It would look something like the attached picture. Looking for thoughts on - Will there be an air flow issue with this home made "oval tee"? - If I buy a round full flow tee and squish the round ends into ovals, will that work? Thank you [img]https://cimg2.ibsrv.net/gimg/www.doityourselft.com-vbulletin/522x267/img_0584_web_2e14127e0ff48625d6e390a0d16a9eec6c046142.jpg[/img]

I've had this issue for a bit now but it makes keeping the house warm difficult since it's constantly blowing cold air after the heats off. It's a st9103 board which I've replaced 3 times thinking that was the issue. The limits are closed for sure. The furnace currently has a r7284 oil controller which replaced the prior Carlin 14280(I'm wondering if that was even compatible) The issue is on the st9103 main board, the heat lead ALWAYS has 120v. I've traced the reason for that down to the oil control unit! When L1 is plugged in to the oil control, the main control heat lead is 120v.. I don't know why that is and don't know if I can justify buying a 30 year old used Carlin 14280 for $800.. please help.