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explain how to figure question 6 on the quiz

Three pressures that control the txv:
spring, evaporator, and bulb.
Spring was 10 psig
evap sat temp = 50 = 84 on p/t.
Spring pressure determines the superheat,
bulb pressure opens valve and evap pressure closes valve.
The combination of spring pressure and evap pressure goes against the bulb pressure. Refresh my memory on how to configure the answer on the quiz.


  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Number 6

    Evaporator pressure + spring pressure = 94 psig

    Since the valve is in equilibrium, the bulb pressure is 94 psig. The temperature that will give us 94 psig in the bulb is 55 degrees, so the superheat is 55 - 50 degrees = 5 degrees.
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