Model # 340mav036080ahka
Serial # 1303A12514
2.5 ton AC compressor
Furnace tripped on high limit Code 33 in Dec. has ran fine for 8 yrs.
Changed High Limit-Same issue
Return Air: CFM around 1150 but probably not real accurate measurement
Just for fun cut in a register grill in duct board to give more return air SAME ISSUES.
SO, when furnace trips on limit, if I change filter I have no issue for 7-10days.
High Limit will trip, change filter NO ISSUES FOR 7-9 days
NOTE: It appears when honeywell Chronatherm Prg.Stat calls for a 2* rise from 70-72 is when it is tripping on limit as the stat shows "Recovery" I don't think this is an issue as the stat is just calling for heat to reach set point by "X" time the furnace I don't believe has a "high fire" which would call for more BTU's
This has been going on for 2 mos now. I am using a Flanders pleated filter 16"x25"x1" after removing a 3M tight pleated filter.
Temp Rise is a problem 40-70* running on the 80* side but again if I put a new filter in no problems until the filter gets a little grey/white matter on filter.
SIDE NOTE: I have a Honeywell bypass humidifier which appears to me is blowing a large amount of CFM from supply through the pad and into the return at high temps then mixes with 72* return air even with damper in "summer" which is closed not a tight seal
I can't figure out why 1) if I remove filter temp rise drops dramatically. Clean/NEW filter no issues until 7 to 9 days change filter and all is fine.
Any ideas why slight filter load would cause issue, the filter does not in any way look like it needs to be cleaned, kicking around the humidifier (new pad installed) but how would that cause filter issues?
Thanks I am at the end of my rope and 2 service techs are just burning my good money by saying "change the filter" which to me every week is not an acceptable solution.
I am in Indianapolis/Brownsburg IN.
Thanks need suggestions...