Final answer:
In a pressuretrol, the main burner ignites based on a pressure differential, thereby maintaining safe and efficient boiler operation.
Step-by-step explanation:
In a pressuretrol, the main burner starts on the basis of a pressure differential. A pressuretrol is a device used in steam boilers to control the pressure of the system. The main burner will ignite when the pressure drops to a preset level, typically at a lower pressure. This pressure differential serves to maintain the appropriate pressure within the system by modulating the operation of the boiler burner. It is vital to calibrate this accurately to ensure safe and efficient boiler operation.
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