Today I arrived and was shown where the make-up air unit is that is not heating. I checked the control box and confirmed that there is a signal leaving it for heating mode and the line voltage is in the proper range. The fan does operate however the burners did not light. The breaker box for this equipment was located and the unit was reset. It did not return to heating. Due to the location of the equipment (roof height) a scissor lift will need to be brought in for access to the make-up air unit. Information was gathered and relayed for a diagnostic quote that includes scissor lift delivery, drop off and usage. Thank you, Jon