The limit switch is the Most Important safety devise!!! Dont ever bypass it .
150-20f 150 would be the temp it will open and shut off burner with a 20 degree reset.
A furnace model number and picture of the old part are very helpful.
We know that's a blower switch.
The previous member listed the temperature but the case type is in question. How to insert pictures.
The numbers on a part are not necessarily a part number.
313245 is an older limit switch. I show this as a replacement.... 313245 - replacement
Figured out my problem.
Furnace was short cycling. Put in new filter and cleaned flame sensor. Didn’t help. At first, burner was cutting off once then starting again. As weeks passed It cut off twice, then three times, and fourbefore restarting and reaching set temp. Searched for new limit switch but could never find correct one. Tried to test switch by running without filter just one cycle. It worked correctly. Had been running a FFR7 filter for 6 months. Bought a FFR5 filter which looks exactly the same. Furnace now runs fine. Thought the FFR numbers referred to quality of filter not filtering ability. How much did I save for service call and new limit switch, 400?
My modulating furnace just seems to turn on low speed for a while when the thermostat calls for heat, then gradually ramps up to full fan speed and burner. When it finally reaches the temp set point, it turns off pretty quick and usually overshoots the temp half a degree or so too. There seems to be no in between speed for this "modulating" furnace.
I just swapped out to a R7184B for a R7284 resideo oil primary control. I have attached all the wires which have been color-coded identically to the original controller. However, when I call for heat, I get no ignition. I know all the wiring is correct because the original well controller still works however, the new one does not ignite at all so I wonder if there is a setting I am missing, I have attached some pictures. Please let me know if anybody has suggestions. This is an Beckett oil hot air furnace.
[img]https://cimg9.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/f3fd3b00_eb93_4155_9a15_b0fd6892a090_025f5c82fa2ef9ccb9fb6548c9365a08f87ca201.jpeg[/img]
[i]Wiring of new controller[/i]
[img]https://cimg2.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/0190b88f_e76c_49df_bac1_f9a69fd2ab25_c61d983276c05fadc09de223fc9cadc274a17a15.jpeg[/img]
[i]Oil burner[/i]
12-15-22, 08:25 AM
