[psr918]

the mfg label says inner city products out of Texas, there is no brand name that i can find. My house is at about 59 in the basement, and 64 on the main floor, of couse this sort of thing happens when it is zero outside, but my furnace is not functioning the way it should. the control for the unit is a white-rodgers furnace control, model # 50A50-110 and it shows me 2 different trouble codes. first off, the small blower above, which i believe is for removing fumes, it comes on just before the burner, the igniter starts to glowand then the burner lights and the igniter goes out. about 10 seconds later the blower stars and the furnace runs for about3 minutes or so, and the burner shuts off. i get a 4 flash trouble code from the control while the blower is in the "cool down ". the code reads as "open high limit switch" . Then sometimes it changes habit and after the burner comes on it only stays on for about 10 seconds then shuts off, the code flashes 6 times now, and there is no translation for 6 flash code.
can anyone make heads or tail on this?

Paul

[conradmech]

sounds like you have a dirty filter. this causes the heater box to over heat. this opens the high limit and causes it to need to cool down.