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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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How do I fix a limit switch being open on a furnace model #

Customer Question

How do I fix a limit switch being open on a furnace model # DLASO75BDD
JA: Did you check the furnace's filters?
Customer: It doesnt have any filters. Its a direct forced air furnace
JA: Do you plan on doing the work yourself?
Customer: Yes if possible
JA: Anything else we should know to help you best?
Customer: Theres a flash code that blilnks 4 times. Says its due to a limit switch being open. Need to know how to close it
Submitted: 5 months ago.
Category: HVAC
Expert:  Rick replied 5 months ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

You can try resetting the rollout switch(es) (see attached pic for typical). They are located just outside the burner chamber. Turn off the power then press the small button between the 2 leads to reset it. If it clicks you have reset it and the unit will fire up when you turn the power back on with any luck. If it doesn't click it wasn't tripped.
Check to be sure there isn't more than one by tracing the leads connected to the switch.

Expert:  Rick replied 5 months ago.

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