Furnace blower on - no Heat
I have a Carrier furnace with an automatic ignition. The fan is constantly running but it is not heating.
Additional Information:
Model 58PAV: The Red Led Status light is rapidly flashing - which according to the manual means 'Line voltage (115VAC) polarity reversed. If twinned, refer to twinning kit instructions'. I do not have a clue what 'Line voltage (115VAC) polarity reversed... ' means. The Furnace was working fine last year and no one touched any wires -- how did the polarity get reversed?
I will really appreciate if someone can explain to me what can I check and how?
Thanks