A.C.R. Copper Oil Return Trap (P-Trap)
The copper trap that helps oil climb back to the compressor when the suction line rises.
AirGreen codeAG-RC-00903
514 316-2973 · sales@airgreen.ca
Quick facts
The oil return trap, or P-trap, is an A.C.R. copper U-shaped fitting brazed into the suction line, at the bottom of a vertical riser. It helps the compressor oil, which travels with the refrigerant, make its way back up to the compressor instead of sitting in the piping.
Why a trap on the suction line
A small amount of oil always leaves the compressor with the refrigerant. In a horizontal or downward line, it returns without difficulty. In a riser, it tends to fall back down. The trap holds it in the U; the suction gas then carries it upward. This is the typical case of an outdoor unit installed on a roof or balcony, higher than the indoor unit, and of commercial circuits where the compressor sits up high.
Seven diameters, from 5/8 in to 2-1/8 in
The trap is available for suction lines of 5/8, 3/4, 7/8, 1-1/8, 1-3/8, 1-5/8 and 2-1/8 in outside diameter. Use the suction line diameter given in the unit's manual.
Follow the manufacturer's instructions
- The installation manual states whether a trap is required, based on the height difference between the units.
- On a long riser, the manufacturer may call for a trap at regular intervals.
- Braze under a light flow of dry nitrogen and insulate the trap like the rest of the suction line.
Line routing and refrigerant work are reserved for a qualified refrigeration technician.
Supplied and installed by AirGreen in Greater Montréal
Our refrigeration technicians route the lines and install the required traps in Montréal, Laval, Longueuil, on the South Shore and on the North Shore. RBQ licence 5645-9605-01. For availability or a quote, call us at 514 316-2973 or email sales@airgreen.ca with the diameter and quantity.
Bringing oil back to the compressor
In a riser, oil tends to drain back down; the trap holds it and the gas carries it up.
- Outdoor unit installed higher than the indoor unit (roof, balcony, upper floor)
- Long vertical suction risers
- Commercial refrigeration circuits with the compressor up high
- Risers split into several sections, per the maker’s instructions
7 sizes, one page
Each size has its own AirGreen code. Tap a row to select it.
| Diameter | AirGreen code |
|---|---|
| 5/8 in | AG-RC-00901 |
| 3/4 in | AG-RC-00902 |
| 7/8 in | AG-RC-00903 |
| 1-1/8 in | AG-RC-00904 |
| 1-3/8 in | AG-RC-00905 |
| 1-5/8 in | AG-RC-00906 |
| 2-1/8 in | AG-RC-00907 |
Outside diameter of the suction line tube, in inches.
Specifications
From the manufacturer’s documentation. A value the manufacturer does not publish is not listed.
What to know before installing
- The trap goes on the suction line, at the bottom of a vertical riser.
- The equipment maker states when a trap is required and at what height interval.
- Use the suction line size given in the equipment manual.
- Braze with a light flow of dry nitrogen; this work is reserved for a qualified technician.
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Frequently asked questions
When is an oil trap needed?
Usually when the suction line rises toward a compressor placed higher up, for example an outdoor unit on the roof. The equipment manual says whether one is needed and at what interval.
Which line does it go on?
The suction (gas) line, the larger of the two, at the bottom of the riser.
Why does the oil need to come back up?
The compressor needs its oil. Some of it travels with the refrigerant; if it stays trapped in the piping, the compressor can run short.
Can you install it?
Yes. Our technicians lay out the line route and install the required traps, everywhere in Greater Montréal.
Oil traps to protect your compressor
Tell us the size and the quantity: we confirm availability and send you a quote. Or let our technicians install it for you.
Specifications from the manufacturer’s documentation, checked on October 7, 2026.