Macurco 70-0726-LEL-M R-455A Refrigerant Leak Detector
The Macurco 70-0726-LEL-M is an RD-VRF Series refrigerant gas detector configured for R-455A in percent of the lower explosive limit. Its NDIR sensor reads R-455A from 0-100% LEL at 1% LEL resolution, with two alarm levels set by default at 10% LEL and 20% LEL.
A combustible refrigerant leak can create an explosion hazard, and any refrigerant leak can deplete oxygen. Reading in % LEL shows how close an R-455A leak is to its lower explosive limit. The 70-0726-LEL-M gives early warning at 10% LEL and a second stage at 20% LEL, has two onboard relays that enable automatic activation of safety measures such as shutting down or isolating refrigerant supply lines, engaging exhaust ventilation or triggering local and remote alarms, and reports to a building management system over Modbus RTU.
Specifications verified October 29, 2026 against the Macurco RD-VRF Series Data Sheet (rev. 1/2026), RD-VRF Specification Rev. 1.1 (8.19.25) and the Macurco VRF Ordering Guide.
Best For
Continuous refrigerant leak monitoring in VRF (variable refrigerant flow) systems and related applications, including:
- Hotels
- Apartments
- Senior living
- Hospitality
- Restaurants
- Retail
- Hospitals
- Universities
- Multi-family
- Commercial offices
Warranty
Macurco backs the 70-0726-LEL-M with a two-year limited warranty.
Key Features
NDIR sensor for R-455A
Measures R-455A over 0-100% LEL at 1% LEL resolution, with a 10-year sensor life and end-of-life notification.
Two alarm levels, two relays
Relay 1 defaults to 10% LEL and Relay 2 to 20% LEL, both adjustable. Each SPDT (Form C) relay is rated 2.0 A at 30 VDC.
Modbus RTU as standard
The RS-485 serial output connects the detector to a building management system for central monitoring.
One model for 24 V or 120 V
Powers from 14 to 24 VDC, 14 to 32 VAC or 120 VAC at 50 to 60 Hz, so one part covers low and line voltage sites.
Flush mount on a standard box
Installs on a double gang box or 4x4 electrical box with a low profile white polycarbonate face plate, IP42.
Built-in display and cal port
A 75 dBA (at 10 ft) buzzer and RGB LED alarm locally. A hidden display and buttons handle setup, testing, addressing and buzzer silence. Yearly calibration is recommended through the built-in cal port.
ZOT Supply is an authorized distributor of Macurco products.
Technical Specifications
| Sensing | |
|---|---|
| Target gas | R-455A |
| Measurement range | 0-100% LEL |
| Resolution | 1% LEL |
| Sensor type | NDIR (non-dispersive infrared) |
| Default alarm levels | Low 10% LEL (Relay 1), high 20% LEL (Relay 2), field adjustable |
| Life expectancy | 10 years with end-of-life notification |
| Calibration | Yearly calibration recommended; built-in cal port; field calibratable with Macurco Cal-Kit 1 and the appropriate gas and concentration |
| Power | |
| Supply voltage | 14 to 24 VDC or 14 to 32 VAC; 120 VAC, 50 to 60 Hz |
| Power consumption | 3 W max at 14 to 24 VDC or 14 to 32 VAC; 4.3 W max at 120 VAC |
| Current draw | 24 V: 48 mA normal, 74 mA full alarm; 120 VAC: 21 mA normal, 36 mA alarm |
| Outputs and Interface | |
| Relays | 2 SPDT (Form C) relays, 2.0 A at 30 VDC |
| Digital output | Modbus RTU, RS-485 |
| Visual indicator | Multicolor RGB LED: green power, red blinking alarm, amber blinking fault |
| Audible indicator | Built-in buzzer, 75 dBA at 10 ft |
| Display | Internal hidden display for configuration, testing and verification; buzzer silence, relay control and addressing |
| Panel compatibility | Macurco DVP-1200 Series |
| Environmental and Mechanical | |
| Operating temperature | 14°F to 122°F (-10°C to 50°C) |
| Operating humidity | 0-95% RH non-condensing |
| Enclosure | Low profile white polycarbonate, IP42 |
| Mounting | Double gang box or 4x4 electrical box, flush mount face plate |
| Size | 5.157 in. H x 5.088 in. W x 1.861 in. D |
| Shipping weight | 0.5 lb (8 oz.) |
| Compliance and Warranty | |
| Certifications | REACH / RoHS |
| Buy American Act | Listed as compliant (Macurco certificate, October 28, 2026) |
| Warranty | Two-year limited warranty |
Documentation
Frequently Asked Questions
What refrigerant does the Macurco 70-0726-LEL-M detect?
R-455A. The NDIR sensor measures 0-100% LEL at 1% LEL resolution.
What are the default alarm setpoints on the 70-0726-LEL-M?
The low alarm and Relay 1 default to 10% LEL, and the high alarm and Relay 2 default to 20% LEL. Both setpoints are field adjustable with the onboard display and buttons.
What does % LEL mean on the 70-0726-LEL-M?
The reading is R-455A concentration as a percentage of its lower explosive limit, from 0 to 100% LEL in 1% LEL steps.
Can the 70-0726-LEL-M connect to a building management system?
Yes. Modbus RTU over RS-485 is standard. The two SPDT relays, rated 2.0 A at 30 VDC, can also signal ventilation, alarm or shutdown controls.
What power supply does the 70-0726-LEL-M need?
The same model runs on 14 to 24 VDC or 14 to 32 VAC at 3 W max, or on 120 VAC at 50 to 60 Hz at 4.3 W max.
How is the 70-0726-LEL-M mounted?
It mounts on a double gang box or a 4x4 electrical box with a flush mount face plate.
How often does the 70-0726-LEL-M need calibration?
Macurco recommends calibration yearly. The detector has a built-in cal port and is field calibratable with Macurco Cal-Kit 1 and the appropriate gas and concentration. Sensor life is 10 years, and the detector gives end-of-life notification.
Which Macurco control panel works with the 70-0726-LEL-M?
The Macurco DVP-1200 Series digital control panel.
Is the 70-0726-LEL-M Buy American Act compliant?
Yes. Macurco's Buy American Act Certificate of Compliance dated October 28, 2026 lists the VRF Series as compliant. The certificate is linked under Documentation.
- Type:
- Refrigerant Leak Detector
- Refrigerant:
- R-455A
- Measurement Unit:
- % LEL
- Detection Range:
- 0-100% LEL
- Sensor Technology:
- NDIR
- Supply Voltage:
- 14-24 VDC / 14-32 VAC / 120 VAC
- Output Signal:
- Modbus RS-485
- Output Signal:
- Relay
