York Furnace - blower motor only sometimes turning on

12 years ago

My furnace is about 11 years old and to this point has worked perfectly. This summer the A/C ran fine(I live in VA so it runs a lot) and then when the cold weather came I turned on the heat.

When the thermostat turns on the heat I can hear the furnace start up, the exhaust fan turns on, the gas ignites and it burns for a minute or so but the blower motor never turns on and it shuts off. I then get a code for the limit switch opening...which makes sense because the blower motor doesn't turn on.

If I leave it alone for a while it will cool down after about 5 minutes and try again, and will usually then work correctly. Sometimes it works fine the first try, sometimes it takes 2 or 3.

If on the thermostat I change the fan from "Auto" to "On" the blower motor turns on just fine. I'm a relative novice with HVAC but am learning...Can anyone suggest some diagnostics I can do?

Thanks!

Sort by:Oldest

Comments (6)

heatseeker
12 years ago
Okay novice start at the capacitor-good luck- keep being optimistic positiveness is contagious.
harlemhvacguy
12 years ago
You don't list your york mdl# but 11 years old would mean the blower function is controlled in heat by the control board. You most likely have some bad contacts on the heat blower motor relay on control board. Not repairable. you will have to change control board....
Related Professionals
Dedham Air Conditioning & Heating · Cerritos Solar Energy Systems · Chino Hills Solar Energy Systems · Elmhurst Solar Energy Systems · Los Angeles Solar Energy Systems · Bozeman Home Automation & Home Media · Crystal Home Automation & Home Media · Cypress Home Automation & Home Media · St. Louis Home Automation & Home Media · West Palm Beach Home Automation & Home Media · Sugar Hill Home Automation & Home Media · Framingham Center Electricians · Lexington Electricians · Downers Grove Fireplaces · Parkland Fireplaces
heatseeker
12 years ago
Pretty good guess all the way from harlem, How did you determine a bad controller.
harlemhvacguy
12 years ago
because fan runs in fan on(according to him) . ran just fine in a/c according to him the only common thing that doesn't run is low speed fan for heat. low speed fan is turned on by different relay on control board than high speed fan (which works according to poster). can't be cap because cap doesn't work sometimes and not others. can be low on capacitance and overheating motor but it still would not run ok some of the time as stated. best i could do with info given.
jeremyp969
Original Author
12 years ago
Thanks for the suggestions all....not what I wanted to hear for the bad control board. Is there anything I can do to prove it's a bad control board without buying a new one and trying it?
Eric2612
11 years ago
I have the exact same situation, only my heating system is Gibson.

Was it the control board? If you don't mind my asking, do you remember the approximate cost?