The 01UT-5Q is a Belimo passive outdoor air temperature sensor with a NTC 20K thermistor sensing element housed in a UV-resistant orange polycarbonate NEMA 4X / IP65 enclosure. It mounts to an exterior wall using the included A-22D-A09 mounting plate and routes into 1/2" NPT conduit via the included adapter. The signal returns directly to the controller as a resistance — no 24V supply or signal conditioning required.
Outside-air temperature sensing on exterior building walls, rooftop equipment skins, and weather-exposed mechanical platforms. Typical applications include AHU outdoor-air reset, free-cooling lockout, economizer changeover, cold-store and greenhouse monitoring, and wherever outdoor ambient is needed by the BAS.
Key Features
Orange polycarbonate enclosure rated NEMA 4X / IP65 with NBR70 seal. UL94 5VA flame class and UL 2043 plenum compliant for return-air ducts as well as exterior walls.
Ships with the A-22D-A09 mounting plate, dowels, screws, and a 1/2" NPT conduit adapter. No additional parts pull required for a standard exterior wall install.
Factory-trimmed NTC 20K element delivers stable long-term accuracy with no field calibration required.
Passive resistance returns directly to the controller — no 24V supply, no signal conditioning, no scaling required.
Pluggable terminal block accepts up to 2.5 mm² conductors. The block lifts out of the housing for bench-side wiring, then snaps back in — faster than fixed terminals on rooftop installs.
Industry-leading factory warranty backed by Belimo's worldwide service network.
Technical Specifications
| Specification | Detail |
|---|---|
| Sensor Style | Outdoor air temperature sensor — wall mount, internal sensing element |
| Measured Value | Temperature |
| Sensing Element | NTC 20K thermistor |
| Measuring Range | -30...120°F [-35...50°C] |
| Application | Outdoor air |
| Mounting | Exterior wall — A-22D-A09 mounting plate, dowels, and screws included |
| Cable Entry | 1/2" NPT conduit adapter included — cable gland with strain relief, ø6...8 mm |
| Electrical Connection | Pluggable spring-loaded terminal block, max 2.5 mm² |
| Housing | UV-resistant polycarbonate, orange — UL94 5VA |
| Enclosure Rating | NEMA 4X / IP65 (UL Enclosure Type 4X), UL 2043 plenum compliant |
| Protection Class | IEC/EN III, Protective Extra-Low Voltage (PELV) |
| UL Approval | cULus per UL60730-1A/-2-9, CAN/CSA E60730-1/-2-9 |
| UL 2043 Compliance | Suitable for use in air plenums per NEC 300.22(C) and IMC Section 602 |
| Time Constant τ (63%) | Typical 854 s in still air |
| Power Required | None — passive resistance element |
| Weight | 0.26 lb [0.12 kg] |
| Manufacturer | Belimo |
| Manufacturer Part Number | 01UT-5Q |
| Warranty | 5-year factory warranty |
What's In the Box
- 01UT-5.. outdoor air temperature sensor in orange UV-resistant housing
- A-22D-A09 mounting plate (S-housing)
- 1/2" NPT conduit adapter
- Mounting dowels and screws
No separate flange, thermowell, or mounting hardware purchase required. Pluggable terminal block is included as part of the housing.
Documentation
Frequently Asked Questions
Does this need 24V power?
No. The 01UT-5Q is a passive resistance temperature sensor — the controller reads its element directly through the analog input. No 24V supply or signal conditioner needed.
What sensing element is in the 01UT-5Q?
The 01UT-5Q uses a NTC 20K thermistor. The letter after '01UT-5' identifies the element: A=Pt 100, B=Pt 1000, E=Ni 1000 (JCI), L=NTC 10K Type II, M=NTC 10K Type III (Precon), Q=NTC 20K. Match this to your controller's input curve.
Where should I mount this on the building?
Belimo recommends mounting on a north-facing exterior wall, shaded from direct sun, at least 6 ft above grade and away from exhaust vents, dryer vents, and AC condenser discharge. The orange housing is UV-resistant for direct exposure when shaded mounting isn't practical, but a north wall gives the most representative reading of true ambient.
What is the response time of this sensor?
The published time constant τ (63%) is approximately 854 seconds in still air — about 14 minutes to reach 63% of a step change. This is normal for outdoor air sensors with a weatherproof enclosure and is appropriate for OA reset and economizer changeover, where slow-moving averages matter more than fast response.
What is included in the box?
Each 01UT-5.. ships as a complete wall-mount kit: the sensor in its orange housing, the A-22D-A09 mounting plate, dowels, screws, and a 1/2" NPT conduit adapter. No separate mounting hardware needs to be purchased.
Is the housing rated for plenum installation?
Yes. The housing is UL 2043 compliant for use in air plenums per NEC 300.22(C) and IMC Section 602. Outdoor wall mount is the typical use, but plenum-side installation inside an outdoor-air intake duct is also acceptable.
Does it work with my BAS?
Any BAS controller with a temperature input configured for the NTC 20K curve will read this sensor directly. See the linked Resistance Characteristics PDF for the full curve table at standard temperature points.
How is this different from the 01DT duct sensor?
The 01DT is a duct-insert probe sensor with a stainless steel probe penetrating the duct wall. The 01UT is a wall-mount sensor with the element internal to the housing — no probe, no flange, no thermowell. Use 01UT for true outdoor ambient on exterior walls; use 01DT (or its outdoor-air-intake variant) for sensing the air inside an OA intake plenum.
- Sensor Type:
- Outside Air
- Output Signal:
- Temperature Only
- Temperature Element:
- 20K Thermistor
- Humidity Element:
- None
- CO2 Element:
- None
- VOC Element:
- None
- Display:
- No Display
- Setpoint:
- No Setpoint
- Override:
- No Override
- Supported Protocols:
- None
- Enclosure:
- NEMA 4X Enclosure
