We have 2 Reznor F-100 unit heaters that share a common 7" b-vent that extends through the roof with a rain cap. The units are no more that 30" apart. The unit that connects to the branch of the 7" tee is cutting out on high limit. if i replace the tee with a wye and 45 and lengthen the piece on the roof will that help with drafting. We have 4 other units that are individually vented and we are not having this issue with any of them.
edit: these pictures are all rotated 90 degrees counter clockwise, I don't know how to rotate them before attaching
Are these units set up with the option CA mechanical exhaust blower or true gravity/ natural draft? What is your input BTU rating, the size of both appliance collars, the total vent rise to the common vent and the total vent height? Single stage or two stage gas valve?
No mechanical vent, strictly gravity, i believe the total BTU's for both units is 200,000, collars are 6" oval to 6" round, the total lenght from unit to the 7" tee is no more than probably 24" total developed length, single stage gas valve