ICP PHAD60N1K1 Installation Instructions Manual

ICP PHAD60N1K1 Installation Instructions Manual Manual pdf 15 page image

I Single Package Heat Pumps7. EconomizerAccessoryInstallation InstructionsNOTE: For installation and wiring of economizersee"Low Voltage Wiring of Economizer Option"(pg.10).The purpose of an economizer is to:• Provide cool outdoor air to the conditioned spaceduring the cooling cycle to minimize the use of com-pressors.• Bring outdoor air into the conditioned space to meetminimum ventilation air requirements whenever thecirculation blower is running.logic module also controls the compressor staging basedon the thermostat input.The minimum opening position of the outdoor air dampersis field adjustable. It is set on the logic module of modulat-ing economizers or on the actuator motor of three-positioneconomizers.The outdoor air enthalpy sensor is factory installed on theoutdoor air dampers. The enthalpy change-over point isadjustable on the logic module.Theory of OperationThe economizer has two sets of dampers that are mechan-ically linked together. The outdoor air dampers regulate theintake of outdoor air and the return air dampers regulatethe flow of return air (see FIGURE 12). When the outdoorair dampers modulate open, the linkage causes the returnair dampers to modulate closed. A barometric relief damp-er is installed in the return air side of the system. It relievesany positive pressure in the unit created by the economiz-er.The economizer is controlled by a logic module which fieldconnects to the unit controls through a harness plug. TheA mixed air sensor is field installed in the blower inlet. Themixed air sensor keeps the mixed air above 56°F (13.3°C).See the economizer installation instructions for the locationof the mixed air sensor.A positive pressure is created in the building when the out-door air dampers open and the return dampers close. Thispressure must be vented or the air will not circulate proper-ly. This is the function of the barometric relief dampers. Apositive pressure forces the passive exhaust dampers toswing open.The outdoor air dampers open to the mininum position foroutside air whenever the circulation blower is ON in thecooling or heating mode.FIGURE 12 J Typical Downflow EconomizerOutdoor Air DampersMixed Air SensorActuator Motor andLogic Module80-50-28bReturn AirDampers