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Piston
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johnjohn89
Member Posts: 100
Why charge wet bulb and dry bulb when system use piston metering device ? And why txv doesn’t charge by wet bulb and dry bulb ?
0
Comments
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As far as I know with a fixed orifice device like a piston you charge by superheat.
With a txv you charge by subcooling because the txv controls superheat, so you can't really charge by it. Personally I watch superheat as well with a txv and adjust the txv if possible to get both superheat and subcooling where they need to be .
Subcooling is really just showing you how much reserve liquid refrigerant you have backed up in the condenser.
Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment1 -
because with fixed metering device a greater portion of the refrigerant is used to remove the latent heat plus the sensible heat. so on a humid day your superheat will increase due to the higher latent heat load on the evaporator coil.
with a txv it will just open up to maintain the proper superheat due to the increased load.0 -
ChrisJ said:As far as I know with a fixed orifice device like a piston you charge by superheat.
With a txv you charge by subcooling because the txv controls superheat, so you can't really charge by it. Personally I watch superheat as well with a txv and adjust the txv if possible to get both superheat and subcooling where they need to be .
Subcooling is really just showing you how much reserve liquid refrigerant you have backed up in the condenser.
Ture thanks
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pedmec said:because with fixed metering device a greater portion of the refrigerant is used to remove the latent heat plus the sensible heat. so on a humid day your superheat will increase due to the higher latent heat load on the evaporator coil. with a txv it will just open up to maintain the proper superheat due to the increased load.0
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