TL;DR
A fixed orifice metering device is the simplest refrigerant flow control in an air conditioner or heat pump: a precisely drilled piston or capillary tube that drops liquid refrigerant to evaporator pressure through an opening of constant size, with no ability to adjust to changing load. Charging a fixed-orifice system is done by the superheat method, unlike TXV systems charged to subcooling.
What it means
A fixed orifice metering device is the simplest refrigerant flow control in an air conditioner or heat pump: a precisely drilled piston or capillary tube that drops liquid refrigerant to evaporator pressure through an opening of constant size, with no ability to adjust to changing load. Charging a fixed-orifice system is done by the superheat method, unlike TXV systems charged to subcooling. Cheap and nearly failure-proof, it gives up efficiency at part load, which is why it survives mainly in budget equipment and older systems.
Where it sits in the glossary
Fixed orifice metering device is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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