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York Gy9s trouble

gurn1050
gurn1050 Member Posts: 3
in Gas Heating

I have a York furnace, model GY9S100C16UP11J that has stopped working.

4 flashes on the controller board-limit switch open

Jumped limit switch, no joy.

Jumped pressure switch, still no joy.

Bad controller board?

The furnace will run for several hours if turned off for 6 or 7 hours…

Anyone have any ideas?

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,532

    Do you have a picture of the wiring diagram? There may be more than one limit switch.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • gurn1050
    gurn1050 Member Posts: 3

    Sorry, I don't have a wiring diagram.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,532
    edited December 19

    I'm not sure if this is your system diagram, but it is for a York furnace and it appears that there are 4 switches on the "limit" circuit that can be "open". ILPS is the burner box pressure switch, LS1 is the primary limit switch, LS2 is a limit switch on the inducer fan and ROS1 is a roll out switch. If you check continuity of each switch and check if there is a reset button on each of them, you may find your problem.

    Screenshot 2024-12-19 at 5.51.15 PM.png

    That circuit starts at Pin # 1 on the 12 pin Molex plug as a Red Wire and goes to the LS1and then to LS2 where it splits to 2 white wires. One of the white wires goes returns to pin 7 on the Molex and the other white wire continues to ILP where it connects to a blue wire that returns to Pin 10 on the Molex. Check those 4 limit switches to find your problem.

    EDIT: ROS1 is connected with a brown wire to pin 11 on the Molex and a black wire to pin 2 on the Molex. that may also have a reset button in the center of it.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • gurn1050
    gurn1050 Member Posts: 3

    Thanks! On it…

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,532

    ROS1is connected with a brown wire to pin 11on the Molex and a black wire to pin 2on the Molex. that may also have a reset button in the center of it.

    This is what a limit with a manual limit

    Screenshot 2024-12-19 at 6.27.35 PM.png

    might look like

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • mattmia2
    mattmia2 Member Posts: 11,029
    https://forum.heatinghelp.com/discussion/comment/1827999#Comment_1827999

    It might be looking for the pressure switch to transition from open to closed when it starts the inducer and it isn't smart enough to tell you that the pressure switch is stuck closed too.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,590

    Can't be a manual reset limit as the op stated if it is shut down for 6-7 hours it will then run.

  • 109A_5
    109A_5 Member Posts: 1,765

    Hello gurn1050,

    " The furnace will run for several hours if turned off for 6 or 7 hours… "

    With these symptoms is could be a bad (failing) solder joint on the control board.

    Not sure if this is applicable to your unit. You did not mention the LED color.

    image.png

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System

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