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$89.40Ships in 3-5 Business Days
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$89.40Ships in 3-5 Business Days
Moisture, acid and debris are the three things that kill refrigeration and air conditioning systems from the inside. A filter drier is the system's last line of defense against all three. It traps water molecules before they can freeze at the metering device or react with oil to form acid, and it catches copper fines, flux, brazing scale and sludge before they reach the compressor valves or plug a TXV. A sight glass with a moisture indicator lets you see what is happening in the liquid line without hooking up gauges.
This category covers Supco liquid line driers, suction line driers, bi-flow heat pump driers, copper spun driers for appliances and small refrigeration, strainers, and sight glasses with moisture indicators, including A2L-rated models for the newer mildly flammable refrigerants. Techs buy these on nearly every sealed-system repair, because replacing the drier any time the system is opened is standard practice. Appliance repair shops buy copper spun driers by the box for refrigerator and freezer work.
A filter drier is a shell packed with desiccant, usually molecular sieve, activated alumina or a blend of the two, formed into a solid core or loose beads. Molecular sieve has pores sized to capture water molecules while letting refrigerant pass. Activated alumina adds acid-removal capacity. A fine mesh or filter pad at the outlet holds back particles. Refrigerant flows through the core, gives up its moisture and contaminants, and continues on clean.
Different locations call for different designs:
A sight glass is a window in the liquid line. A full, clear glass under stable running conditions shows a solid column of liquid. Bubbles can mean low charge, a restriction upstream or flash gas, though they can also appear briefly during startup or with some refrigerant blends. The moisture indicator is a chemically treated element in the center of the glass that changes color with moisture content, typically green for dry and yellow or another warning color for wet. Check the indicator's color legend, since it varies by manufacturer.
Decide first whether you need a liquid line, suction line or bi-flow drier. Heat pumps with a common liquid line require a bi-flow drier. Use a suction line drier only where the design and the cleanup procedure call for one.
Match the line size, such as 1/4, 3/8, 1/2 or 5/8 inch. Sweat connections are brazed in place and are the norm on residential split systems. Flare connections allow removal without brazing and are common on some commercial and service applications. Copper spun appliance driers come in specific inlet and outlet configurations, so match the cap tube and line connections.
Drier capacity is rated by refrigerant flow, typically in tons, and by water capacity. Choose a drier rated for the system tonnage and refrigerant. Undersizing creates excessive pressure drop. Oversizing is generally fine within reason and gives more moisture capacity, though it adds to the charge in the drier shell.
Confirm the drier and sight glass are rated for the refrigerant in the system. With R-454B and R-32 equipment entering the market, use components the manufacturer rates for A2L refrigerants and the system's working pressure. Desiccant selection also matters for POE oil systems, which absorb moisture readily.
Many OEM driers are standard sizes with manufacturer-specific part numbers. Supco cross-reference data and product specifications help match them by connection size, type and capacity. On appliances, the OEM part number from the parts list is the fastest route to the correct copper drier.
| Type | Installed Location | Primary Job | Typical Use |
|---|---|---|---|
| Liquid line drier | Between condenser and metering device | Moisture, acid and particle removal | AC split systems, refrigeration, every sealed-system repair |
| Suction line drier | Ahead of the compressor | Acid and contaminant cleanup | After compressor burnout or heavy contamination |
| Bi-flow drier | Heat pump common liquid line | Filtration in both directions | Heat pumps and reversing systems |
| Copper spun drier | Condenser outlet ahead of cap tube | Moisture and particle removal | Refrigerators, freezers, ice machines, small equipment |
| Strainer | Ahead of metering device or solenoid | Particle removal only | Protecting valves and cap tubes |
| Sight glass / moisture indicator | Liquid line, typically after the drier | Visual check of liquid flow and moisture | Refrigeration and commercial AC service |
Drier replacement is sealed-system work. Recovering refrigerant requires EPA Section 608 certification, and brazing on a charged or improperly purged system is dangerous. This work belongs with a certified technician.
Supco has supplied sealed-system parts to the trade since 1945, and HVAC365 carries its driers, strainers and sight glasses so techs can match common sizes in one place. Product pages list connection sizes, types and specifications, with cross-reference and spec sheet details where available. Orders ship in 3-5 business days.
Yes, that is standard practice. Once exposed to air, the desiccant absorbs moisture and loses capacity. A new drier is inexpensive compared with a moisture-related compressor or TXV failure.
Not on a common liquid line that sees flow in both directions. Use a bi-flow drier designed for heat pumps, unless the manufacturer's design places one-way driers in separate check-valved circuits.
It depends on the cleanup. Many techs install a suction line drier after a burnout, monitor pressure drop across it, and remove or replace it once acid tests come back clean. Follow the drier and compressor manufacturers' recommendations.
On many indicators, yellow or a similar warning color means moisture is above a safe level. Check the legend on that specific sight glass. A wet reading calls for drier replacement and, if moisture is severe, a deeper evacuation.
No. Bubbles can come from low charge, a restriction upstream such as a plugged drier, high head pressure swings, startup conditions or refrigerant blends. Confirm charge with superheat and subcooling before adding refrigerant.
They are evaluated and rated for use with mildly flammable A2L refrigerants such as R-454B and R-32. Always use components the manufacturer lists for the refrigerant and pressures in the system you are servicing.
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