Armstrong offers three configurations in its automatic purger line: mechanical purgers, electric single-point purgers and multi-point purgers.

Mechanical purgers. The mechanical version incorporates an air vent and inverted bucket mechanism for non-electric manual operation.
Electric single-point purgers. This style of Armstrong purger incorporates an inverted bucket mechanism and an electronic float switch assembly. The electronic float switch serves two functions: 1) To tell the controller if there is a pocket of air at the top of the purger and 2) to tell the controller the temperature of the refrigerant inside the body. These two functions ensure that the purger is not discharging non-condensable gases at a temperature too high for efficient and cost-effective purging.
Multi-point purgers. The completely automatic electronic multi-point purger uses a float switch to tell a PLC control what is happening in the purger body at all times. Depending on the refrigerant level in the purger body, the float switch has the controller activate the appropriate solenoid valve to maintain the liquid level and temperature inside the purger body.