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evaporator heat load

when an evaporator experiences a heat load increase, the suction pressure

remains constant?


varies up and down?


it would increase correct?


  • Eugene SilbersteinEugene Silberstein Member Posts: 1,380
    It Depends

    It depends on the metering device the system is operating with. If the system is equipped with an automatic expansion valve, the low side pressure will remain constant. This is because the purpose of the AEV is to maintain constant evaporator pressure regardless of the load on the system. If, however, the system is operating with a capillary tube or a thermostatic expansion valve, the suction pressure will increase.

    If the system has a capillary tube, the suction pressure will increase and so will the evaporator superheat. If the system has a thermostatic expansion valve, the suction pressure will increase but the evaporator superheat will remain constant.

    Hope this helps.
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