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Macurco Gas Detection

Variable Refrigerant Flow

Variable Refrigerant Flow (VRF)/Variable Refrigerant Volume (VRV) are one and the same. While being popular in Asia and Europe for some time, these systems have just recently started growing traction in the US market. A VRF system is a high-volume refrigerant cooling and heating system consisting of outdoor condensing units connected to multiple indoor fan-coil units via refrigerant piping to provide cooling and heating to individual zones. These highly efficient systems provide design flexibility, cost-effective installation, and energy savings.

Application Overview

Variable Refrigerant Flow (VRF) is a type of HVAC system that offers high energy efficiency and flexibility in commercial and residential buildings. VRF systems use refrigerant to transport heat from the outdoor unit to multiple indoor units, allowing for individualized temperature control in each zone. This technology allows for precise temperature control, zoning capabilities, and efficient operation by adjusting the amount of refrigerant supplied to each indoor unit based on its specific cooling or heating needs.

VRF systems are suitable for a wide range of applications, from small office buildings to large multi-use complexes. They are known for their quiet operation, easy installation, and low maintenance requirements, making them a popular choice for modern buildings looking for efficient and customizable heating and cooling solutions.

Common VRF Applications





Nursing Homes


Gases Found

  • Refrigerant: R-410A, R-32, R-134a, R-404A, R-407C, R-449A, R-1234ze, Others

  • For additional refrigerant gases contact Macurco.


Why is a gas detector important?

The Macurco RD-VRF Refrigerant Gas Detector is designed to provide continuous refrigerant monitoring in applications that pose an oxygen-depleting environment in the event of a refrigerant leak and accumulation that poses a significant safety issue. A VRF detector provides advanced warnings via low detection alarms and notifications.

Where would one find a VRF system?

Typical applications include hotel rooms, senior care, dorms, hospitals, commercial offices, classrooms, and other occupied spaces, taking advantage of the cost-saving benefits of VRF technologies for heating and cooling.

How does the RD-VRF detector work?

The RD-VRF Refrigerant Gas Detector comes standard with 2 alarm levels to activate two onboard relays that can be used to control valves to isolate or shutdown refrigerant supply lines, engage exhaust fans, provide notification alarms, and communicate to a Building Management System (BMS).

What standard guides VRF systems?

ASHRAE 15 specifies safe, design, construction, installation, and operation of refrigeration systems. The standard applies to the design, construction, test, installation, operation, and inspection of mechanical and absorption refrigeration systems, including heat pump systems used in stationary applications.

RD-VRF Office Layout

An RD-VRF is normally mounted low in the room on a wall or column one foot above the floor in a central area where air movement is generally good. Generally, Macurco recommends spacing 30-foot centers, 900 square feet per detector (84 sq. meters). The coverage depends on air movement within the room or facility. Extra detectors may be needed near any areas where people work or sleep or where the air is stagnant. The RD-VRF mounts on a 2-gang PVC electrical box supplied by the contractor. Mount the unit near the discharge of the fan coil.

VRF Safety Standards

The safety classification of R-410A in Standard 34 is group 1 (meaning non-toxic and non-flammable), has no ozone depletion potential, and meets the stringent mandates of the Montreal Protocol and the U.S. Environmental Protection Agency. However, due to the ability to displace oxygen, Addendum L to ASHRAE Standard 34-2010 has established the maximum Refrigerant Concentration Limit (RCL) to 26 lbs/1000 ft3 of room volume for occupied spaces for Institutional Occupancies; the limit is reduced to 50% (13 lbs. /1000 ft3). Since the indoor unit fan coils are in direct contact with the air being distributed, the system is classified as a Direct System according to Standard 15. By definition, a Direct System is also classified as a High Probability system, meaning that a leak of refrigerant can potentially enter into occupied space.

Common Applications