Calibrated GasR134A
Measuring Range0-1000 ppm
Output Signal0-10 VDC, 3-wire
Alarm Relay1 N.C., 1 A
Local AlarmLED + 82 dB Buzzer
MountingRecessed, single-gang
The Senva TG0R-3B is a recessed room-mount refrigerant leak detector for VRF systems and other occupied spaces. It uses a metal oxide semiconductor (MOS) sensing element factory calibrated to R134A, reports 0-1000 ppm on a 0-10 VDC 3-wire output, and carries a normally closed alarm relay, a status LED and an 82 dB local buzzer behind a single-gang wall plate. Senva positions the TG0R Series as an A2L refrigerant leak detector for VRF applications such as hotel guest rooms, schools, multi-family, mixed-use and commercial facilities.
Specifications on this page were verified against the Senva TG0R Series A2L Refrigerant Leak Detector for VRF datasheet and Senva installation instructions document 152-0408-0B, revised 7/8/2024.
Application limit: Senva states in the TG0R installation instructions that the TG Series has not been tested for Life Safety Applications and is not to be used in Life Safety Applications in jurisdictions that require that certification. Senva also states that gas sensors are not a substitute for proper installation, use, or maintenance of gas-emitting equipment. Confirm suitability with the Authority Having Jurisdiction before specifying.
Best For
- VRF systems where a local room-level leak alarm is required, per the applications Senva lists for the TG0R Series
- Hotel guest rooms, schools, multi-family, mixed-use and commercial facilities (applications listed on the Senva TG0R datasheet)
- Retrofits into an existing single-gang box, where a recessed low-profile plate is preferred over a surface enclosure
- Spaces that need both a stand-alone audible alarm and a signal back to the building automation system
- Controllers with 0-10 VDC universal inputs already available on the panel
Warranty
7-year warranty. Senva backs the TG0R Series with a seven year warranty. Senva also states that its liability, whether in contract, in tort, under any warranty, in negligence or otherwise, shall not exceed the purchase price paid for the product, and that Senva is not liable for special or consequential damages. ZOT Supply is an authorized Senva distributor; warranty claims are handled directly with Senva.
Key Features
Normally closed alarm relayThe TG0R provides a normally closed alarm relay rated 1 A at 24/30 VAC/VDC (50/60 Hz) for low-voltage control-system integration. It trips above 300 ppm for 1 hour or above 600 ppm for 15 minutes. Senva specifies no mains connection on this relay.
82 dB buzzer with capacitive touch silenceThe local buzzer follows the same 300 ppm / 600 ppm alarm logic. Hold a hand over the cap touch button for 3 seconds to silence. Senva allows three silences; after the third, gas must drop below setpoint or the device must be power cycled.
Two-stage LED indicationOne long blink per second above 300 ppm signals pre-alarm; one short blink per second above 600 ppm signals alarm. Three blinks every 30 seconds is the end-of-life indication for the sensing element.
Hidden test buttonPress the concealed test button for one second with a small screwdriver and the buzzer sounds while the relay activates for two seconds, which verifies the whole alarm chain without applying gas.
R134A calibration usable as a general-purpose elementSenva states the R134A sensor is factory calibrated to R134A but may be used as a general purpose refrigerant sensor, and publishes the response table below. Any unit may be field calibrated to a specific gas for closer accuracy.
0-10 VDC supply requirementSenva notes that 15-30 VDC or 24 VAC supply voltage is required for full 10 volt output. Size the transformer accordingly; one side of the transformer secondary connects to signal common and a dedicated transformer is recommended.
Technical Specifications
| Power | |
| Power supply | 12-30 VDC / 24 VAC, 24 mA max (15-30 VDC / 24 VAC required for full 10 V output) |
| Transformer note | One side of the transformer secondary connects to signal common. A dedicated transformer is recommended. |
| Output | |
| Analog output | 0-10 VDC, 3-wire |
| Refrigerant output scaling | 0-1000 ppm |
| Alarm | |
| Relay characteristics | N.C., 1 A at 24/30 VAC/VDC (50/60 Hz), no mains connection |
| Relay and buzzer setpoint | Above 300 ppm for 1 hour, or above 600 ppm for 15 minutes |
| LED indication | 1 long blink above 300 ppm; 1 short blink above 600 ppm |
| End-of-life indication | 3 blinks at 30 second intervals |
| Buzzer level | 82 dB |
| Alarm silence | Hold hand over cap touch button for 3 seconds (3 silences maximum) |
| Alarm test | Hidden button; press 1 second, relay activates 2 seconds |
| Refrigerant sensor performance | |
| Sensing element | MOS (metal oxide semiconductor) |
| Factory calibration | R134A |
| Resolution | 1 ppm |
| Life expectancy | Greater than 10 years (typical life expectancy of MOS sensors) |
| Coverage area | 5,000 to 7,500 square feet |
| Calibration interval | 6 months; hold test button 10 seconds to enter cal mode |
| Field calibration | Hold test button 10 seconds to enter cal mode, then apply R134A at 0.2 LPM and 1000 ppm for 5 minutes |
| Other detectable gases | R407A, R407F, R427A, R452B, R507, R448A, R449A, R422A, R422D, R452A, R513A, R514A, R32. Senva states these gases may be detected but sensitivity curves are not available at this time. |
| Environment | |
| Unit temperature rating | -4 to 122 °F (-20 to 50 °C), per the current TG0R datasheet |
| Humidity | 15-95% continuous, 0-95% intermittent |
| Maximum elevation | 2,629 m (8,625 ft) per the current TG0R datasheet; field calibration recommended to maintain accuracy at altitude |
| Enclosure and compliance | |
| Dimensions | 4.45 in. H x 2.7 in. W x 0.5 in. D (depth measured from wall) |
| Mounting | Recessed; fits a standard single-gang box |
| Mounting height | 6 in. above finished floor for refrigerant sensors |
| Compliance | CE, RoHS |
| Country of origin | United States |
Environmental values above follow the current Senva TG0R datasheet where it differs from installation document 152-0408-0B (revised 7/8/2024).
Published response of the R134A calibrated element
Senva publishes the following measured readings when 300 ppm of test gas is applied to an R134A calibrated element. Readings above 300 ppm mean the element over-reports that gas relative to its R134A calibration, which is why Senva describes it as a cover-all general purpose refrigerant element.
| Test gas at 300 ppm | Reading on R134A calibrated element |
|---|---|
| R410A | 450 ppm |
| R407C | 425 ppm |
| R404A | 400 ppm |
| R22 | 370 ppm |
| R134A | 300 ppm |
Installation notes from Senva
- Mount refrigerant sensors 6 in. above finished floor, and confirm mounting height against local and state building codes.
- Do not install the sensor in multi-gang electrical boxes with line voltage or other electrical devices.
- Use installation wire rated 75 °C and above.
- Confirm the supplied insulation covers the entire junction box opening so wall cavity air does not affect the reading.
- Do not install in hazardous or classified locations.
Documentation
Related Senva TG0R Detectors
Calibration accessory: order Senva CALKITHW-R to receive the calibration fitting and regulator used for the 6 month field calibration.
Frequently Asked Questions
What gas is the Senva TG0R-3B calibrated to?The TG0R-3B ships with its MOS element factory calibrated to R134A. Senva states a unit may be field calibrated for a more accurate response to a specific gas.
What is the measuring range and output of the TG0R-3B?The refrigerant output scales 0-1000 ppm on a 0-10 VDC 3-wire signal. Resolution is 1 ppm.
At what concentration does the TG0R-3B alarm?The alarm relay, buzzer and alarm LED follow the same logic: above 300 ppm sustained for 1 hour, or above 600 ppm sustained for 15 minutes. A single long LED blink above 300 ppm is the pre-alarm indication; a short blink above 600 ppm is the alarm indication.
Can the TG0R-3B be used as a code-required A2L leak detector?Senva markets the TG0R Series as an A2L refrigerant leak detector for VRF, but the installation instructions state the TG Series has not been tested for Life Safety Applications and is not to be used in Life Safety Applications in jurisdictions that require that certification. Where a listed refrigerant detection system is mandated by code, confirm acceptability with the Authority Having Jurisdiction.
Will the TG0R-3B detect refrigerants other than R134A?Senva publishes a response table for the R134A calibrated element: at 300 ppm of applied test gas it reads roughly 450 ppm for R410A, 425 ppm for R407C, 400 ppm for R404A, 370 ppm for R22 and 300 ppm for R134A. Because it over-reports other refrigerants, Senva describes the R134A element as a general purpose, cover-all refrigerant element. Additional gases are listed as detectable without published sensitivity curves.
How often does the TG0R-3B need calibration?Senva specifies a 6 month calibration interval for the refrigerant element. Hold the hidden test button for 10 seconds to enter cal mode, then apply R134A at 0.2 LPM and 1000 ppm for 5 minutes. Order CALKITHW-R for the calibration fitting and regulator.
How high should the TG0R-3B be mounted?Senva calls for refrigerant sensors to be mounted 6 in. above finished floor. Check with local and state building codes to ensure the sensor mounting height is in compliance.
How long does the sensing element last?Senva rates the MOS refrigerant element at greater than 10 years typical life expectancy. The unit signals end of life with three LED blinks every 30 seconds.
What supply voltage does the TG0R-3B need?The unit runs on 12-30 VDC or 24 VAC and draws 24 mA maximum, but Senva notes that 15-30 VDC or 24 VAC is required to reach full 10 volt output. One side of the transformer secondary connects to signal common, and a dedicated transformer is recommended.
Is the TG0R-3B made in the USA?Yes. Senva lists the TG0R series in its Buy America / BABAA / TAA / ARRA conformance statement dated 04/21/2026, manufactured in Beaverton, Oregon with domestic component cost exceeding 65 percent, and identifies the country of origin as the U.S.A.
7-Year Warranty. Senva backs the TG0R Series with a seven year warranty. Senva liability shall not exceed the purchase price paid for the product, and Senva is not liable for special or consequential damages. ZOT Supply is an authorized Senva distributor; warranty claims are handled directly with Senva.
- Type:
- Refrigerant Leak Detector
- Calibrated Gas:
- R134A (Multi-Gas)
- Sensor Technology:
- MOS
- Series:
- TG0R
- Enclosure Style:
- Wall (Recessed)
- Analog Output:
- 0-10 VDC (3-Wire)
- Relay Output:
- 1 N.C.
- Local Alarm:
- LED and Audible Buzzer
- Communication:
- None
- Display:
- None
- Country of Origin:
- United States
