When a technician observes "roll out" flames during the main ignition of a standing pilot furnace, what condition is suspected?

When a technician observes "roll out" flames during the main ignition of a standing pilot furnace, the condition that is suspected is low gas pressure. Roll out flames indicate that combustion gases are not being vented properly, and this can be exacerbated by insufficient gas pressure. When gas pressure is low, the burners may not receive enough fuel to achieve a stable combustion process. As a result, the flames may roll out from the burner due to an incomplete combustion process, causing safety concerns.

In a properly functioning system, adequate gas pressure ensures that the burners operate effectively, leading to optimal flame characteristics, proper heat distribution, and safe venting of combustion gases. Observing roll out flames is a critical indicator for technicians to investigate the gas supply and ensure that it meets the furnace's requirements for safe and effective operation.