HPEOK PKQ-204 Suction Line Accumulator (Liquid Trap) | 1/2 inch ODF Brazed, 1.5 L | R22, R134a, R410A, R407C, R502, R507 Compatible

HPEOK PKQ-204 is a liquid trap fitted to the suction line of the refrigeration circuit — technically a suction line accumulator. In the line returning from the evaporator to the compressor, it traps unevaporated liquid refrigerant and ensures that only gas reaches the compressor. Its connection is 1/2 inch ODF brazed; inlet and outlet are the same size.

Why it is needed: a compressor is a gas pump and cannot compress liquid. If liquid comes from the suction line, liquid slugging (hydraulic lock) occurs; the valve plate breaks, the connecting rod bends, and the oil in the crankcase is diluted by liquid refrigerant, leaving the bearings unprotected. The accumulator collects this liquid in its body and returns it to the system by slowly evaporating it.

The small oil return hole at the bottom of the internal U-tube sends the collected oil back to the compressor in a controlled way — so the oil is not trapped in the accumulator. It is fixed to the chassis with the M10 stud on the bottom of the body.

Which Systems It Is Used In

• Heat pumps — liquid enters the suction line when the four-way valve reverses the cycle.
• Systems with defrost — liquid floodback occurs on the return after hot gas defrost.
• Low-temperature applications — blast freezers, deep freezer units.
• Circuits with long off cycles — refrigerant that condenses in the evaporator during shutdown travels to the compressor at the first start.
• Commercial refrigeration circuits with flooded evaporators and variable loads.

Technical Specifications

• Brand / type: HPEOK PKQ-204
• Product type: Suction line accumulator (liquid trap)
• Connection: 1/2 inch ODF brazed (solder) — inlet 1/2 inch, outlet 1/2 inch
• Volume: 1.5 L
• Height: 20.3 cm
• Design pressure: 30 bar (3,000 kPa / 435 psi)
• Operating temperature: −40 °C … +120 °C
• Mounting connection: M10 stud
• Body: Steel, epoxy powder coated
• Certification: CE / PED, CNAS
• Origin: China

Compatible Refrigerants

Refrigerants listed on the product label: R22, R134a, R410A, R407C, R502, R507. It works in HCFC and HFC circuits, with mineral and POE oil.

Size Selection

In the PKQ series, the last digits of the code give the connection size: 204 1/2 inch, 205 5/8 inch, 207 7/8 inch, 208 1 1/8 inch, 209 1 3/8 inch, 210 1 5/8 inch. The accumulator is selected at the same size as the suction pipe diameter; the body volume should be large enough to hold roughly half of the total refrigerant charge in the system. PKQ-204 is the smallest body in the series (1.5 L); the next size up, PKQ-205, is 1.8 L.

Installation Notes

• Mounted upright, with the inlet-outlet ends facing up. In horizontal mounting, the oil return hole loses its function.
• It is placed between the evaporator outlet and the compressor suction, as close to the compressor as possible.
• Follow the arrow or IN/OUT marking on the body; if connected backwards, liquid passes directly to the compressor.
• During brazing, the body is protected with a wet cloth or heat paste; braze under nitrogen flow.
• After installation, do not charge refrigerant before evacuating the circuit.

Frequently Asked Questions

Is a liquid trap the same as a liquid receiver?

No, they sit in different parts of the circuit. The liquid trap (suction line accumulator) is on the low pressure side, fitted in the line returning from the evaporator to the compressor, and protects the compressor from liquid. The liquid receiver is on the high pressure side and stores liquid refrigerant at the condenser outlet. This product is for the suction line.

Which size should I choose?

The accumulator is selected at the same diameter as the suction pipe — this model is for a 1/2 inch line. The body volume should hold about half of the total refrigerant charge in the system; the PKQ-204 volume is 1.5 L.

How is it installed?

It is installed upright, with the connection ends facing up, between the evaporator outlet and the compressor suction. It is fixed to the chassis with the M10 stud underneath. Horizontal mounting disrupts oil return.

How does oil return to the compressor?

There is a small oil return hole at the bottom of the U-tube inside the body. The collected oil is carried through this hole to the compressor with the suction gas in a controlled way, so no oil is trapped in the accumulator.

Which refrigerants is the PKQ-204 used with?

R22, R134a, R410A, R407C, R502 and R507 are listed on the product label. The design pressure is 30 bar (3,000 kPa / 435 psi) and the operating temperature is between −40 °C and +120 °C.

Is an accumulator essential in a heat pump?

In heat pumps, it is normal for liquid refrigerant to enter the suction line when the four-way valve reverses the cycle; that is why the accumulator is one of the key parts protecting the compressor. It is also used in commercial refrigeration circuits with defrost for the same reason.

Can I buy regularly with an invoice as a service company/technician?

Yes, all our sales are invoiced. All orders, including those from service companies and technicians, are placed directly through our website.

How do I track my shipment after ordering?

Your shipment tracking number is sent to your e-mail and phone after ordering; you can follow its status in the “Where Is My Shipment?” section.

Can I return or exchange the product?

Yes. Under Consumer Protection Law No. 6502 you have the right of withdrawal/return within 14 days of delivery. To avoid ordering the wrong model, we recommend that you verify compatibility before ordering. Details are on our “Delivery, Returns and Exchanges” page.