A low pressure control has a "high event" and a "differential" setting. The technician wants the system to turn on at 28 psig and shut down at 2 psig. What would be the proper settings?

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Multiple Choice

A low pressure control has a "high event" and a "differential" setting. The technician wants the system to turn on at 28 psig and shut down at 2 psig. What would be the proper settings?

In this type of control, the high event setting is the pressure at which the system turns on, and the differential is the gap between the turn-on and turn-off pressures. To have the system turn on at 28 psig and shut off at 2 psig, the off pressure must be 28 psig minus the differential. That means the differential should be 26 psig (28 − 26 = 2). So the proper settings are a high event of 28 psig and a differential of 26 psig. Other options would produce off pressures of 4, 0, or 4 psig, which don’t meet the 2 psig off requirement.

In this type of control, the high event setting is the pressure at which the system turns on, and the differential is the gap between the turn-on and turn-off pressures. To have the system turn on at 28 psig and shut off at 2 psig, the off pressure must be 28 psig minus the differential. That means the differential should be 26 psig (28 − 26 = 2). So the proper settings are a high event of 28 psig and a differential of 26 psig. Other options would produce off pressures of 4, 0, or 4 psig, which don’t meet the 2 psig off requirement.

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