How to choose a vacuum pump based on the size and type of an HVAC-R installation?

Vacuum pumping is one of the most critical steps when commissioning a refrigeration or air conditioning system. A properly sized vacuum pump ensures effective drying of the circuit, removes residual moisture, evacuates non-condensable gases, and helps protect the compressor for long-term reliability. But how do you choose the right vacuum pump based on system size and the refrigerant used?

Why is choosing the right vacuum pump essential?

An undersized pump leads to:
•    a very long evacuation time,
•    an inability to reach the target vacuum level (e.g., 500 microns),
•    a risk of residual moisture → acids → compressor damage,
•    poor long-term energy efficiency.

An oversized pump, on the other hand, is not dangerous, but it can be unnecessarily expensive and less convenient to transport.
The right choice therefore depends on three factors:
1.    The internal volume of the circuit (piping + indoor/outdoor units + accessories),
2.    The type of installation (split, multi-split, heat pump, etc.),
3.    The refrigerant (notably R32 = A2L and R290 = A3).

The #1 criterion: suction flow rate (L/min)

The flow rate, expressed in L/min or CFM, determines how quickly the system can be evacuated.
Practical guidelines:
•    < 150 L/min → Small air conditioning systems and commercial refrigeration
•    150–250 L/min → Light commercial / tertiary air conditioning and commercial refrigeration
•    > 250 L/min → Industrial and commercial refrigeration
The ultimate vacuum rating (e.g., 15 microns) is also essential, as it ensures effective dehydration of the circuit.

Which vacuum pump for which type of installation?

Here is a general table to help you size your vacuum pump based on the installation, before introducing LINSTRUMENT models:

Type of installation	Circuit volume	Recommended flow rate
Single split system 2.5–5 kW	Low	~100–150 L/min
Single split 7 kW / small multi-split (2 outlets)	Low to medium	~150–180 L/min
Multi-split 3–5 outlets	Medium to high	~170–250 L/min
Large multi-split / small VRF systems	High	>250 L/min
Air-to-water heat pump (8–16 kW)	Medium to high	~170–250+ L/min
Cold rooms / retail refrigeration	High	>250 L/min
R290 installations (A3)	Critical	ATEX-certified pump required

Overview of LINSTRUMENT vacuum pumps and selection advice

• VPX-240-R32 — 114 L/min
For: small installations – single split systems (2.5 to 5 kW).
This compact pump (< 8 kg) offers an excellent weight-to-performance ratio.
It reaches 15 microns and features: a low-speed brushless DC motor, an integrated vacuum gauge, a solenoid valve, and an anti-spill system.
Ideal for mobile technicians and day-to-day small service work.

• VPX-260-R32 — 170 L/min
For: small to medium installations – single/multi-split with 2 to 3 outlets – heat pumps up to 10 kW.
Same design as the VPX-240, but more powerful (1/2 HP).
This is the ultimate versatile model: fast, A2L-compatible, and still < 8 kg.
The best choice for 80% of standard service jobs.

• VPX-300-R32 — 282 L/min
For: medium to large installations – multi-splits with 4 to 8 outlets – heat pumps > 12 kW – small VRF systems.
With its very high flow rate, the VPX-300 significantly reduces evacuation time while remaining surprisingly lightweight (< 8 kg).
Still equipped with: an integrated vacuum gauge, a solenoid valve, a 3/4 HP brushless motor, and A2L explosion-proof components.
The pump for installers looking for speed and efficiency.

• HVP-260-EX — 170 L/min (ATEX)
For: R290 installations / explosive areas / EX environments.
The only ATEX-certified pump in the LINSTRUMENT range (Ex II 3G). Compatible with all gases: A1, A2L, A3 (R290). Equipped with: a 1 HP explosion-proof motor, a two-stage rotary vane system, an integrated vacuum gauge, a 5 m crystal hose for A3 vapors, IP55 thermal protection, and a high-capacity capacitor.
The mandatory and safe choice for any work with propane.

Conclusion

Choosing a vacuum pump based on the size and type of installation is therefore essential to achieve an effective, fast, and long-lasting vacuum evacuation. It also helps extend system lifespan and increase customer satisfaction.