The 01DT-5ML is a Belimo passive duct-mount temperature sensor with a NTC 10K Type III thermistor (Precon) sensing element on a 4" stainless steel probe, housed in a NEMA 4X / IP65-rated polymer enclosure. It mounts through a single drilled hole via the included flange-style mounting plate, with the integral wiring junction on the duct exterior for clean conduit terminations. Use it directly in air for duct mounting, or with a Belimo thermowell (linked below) for liquid immersion.
Supply, return, and mixed-air temperature in air handlers and rooftop units; in-duct sensing for outdoor-air intake plenums; coil-leaving air; and — with the appropriate thermowell — direct immersion in chilled water, hot water, and condenser water lines.
Key Features
NEMA 4X / IP65-rated polymer housing with cable-gland entry. Suitable for duct exteriors, rooftop equipment skins, and damp mechanical-room environments.
Factory-trimmed NTC 10K Type III element delivers stable long-term accuracy with no field calibration required.
Installs through a single drilled hole using the included flange plate. Integral exterior wiring junction simplifies conduit runs and terminations.
Passive resistance returns directly to the controller — no 24V supply, no signal conditioning, no scaling required.
Pair with the matching Belimo thermowell (linked below) for direct immersion in chilled water, hot water, condenser water, and process loops.
Industry-leading factory warranty backed by Belimo's worldwide service network.
Technical Specifications
| Specification | Detail |
|---|---|
| Sensor Style | Duct mount with stainless steel probe |
| Measured Value | Temperature |
| Sensing Element | NTC 10K Type III thermistor (Precon) |
| Measuring Range | -60...300°F [-50...150°C] |
| Probe Length | 4" |
| Probe Material | Stainless steel |
| Mounting | Single Point Immersion |
| Process Connection | Flange (included) — also compatible with 1/2" NPT thermowells |
| Electrical Connection | Spring-loaded terminals |
| Enclosure Rating | NEMA 4X / IP65 |
| Power Required | None — passive resistance element |
| Manufacturer | Belimo |
| Manufacturer Part Number | 01DT-5ML |
| Warranty | 5-year factory warranty |
Compatible Accessories
Documentation
Frequently Asked Questions
Does this need 24V power?
No. The 01DT 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 01DT-5ML?
The 01DT-5ML uses a NTC 10K Type III thermistor (Precon). The first letter after '01DT-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.
What does the probe length suffix mean?
The last letter encodes probe length: H=2", L=4", N=6", P=8", R=12", T=18". This SKU has a 4" probe.
Can I use this on a water or chilled-water line?
Yes — pair the sensor with the matching length thermowell from the Compatible Accessories section above. For this 4" probe, see the 4" stainless or brass thermowells listed.
Is this rated for outdoor air?
The NEMA 4X / IP65 enclosure handles damp and protected-outdoor environments. For sensing outdoor air specifically, mount the probe inside the AHU outdoor-air intake plenum so the probe reads inlet air while the enclosure stays sheltered. For exposed-to-weather outdoor wall mounting, use the 01UT outdoor-air sensor family instead.
Does it work with my BAS?
Any BAS controller with a temperature input configured for the NTC 10K Type III curve will read this sensor directly. See the linked Resistance Characteristics PDF for the full curve table at standard temperature points.
- Sensor Type:
- Duct
- Temperature Element:
- 10K Type III
- Probe Length:
- 4
- Enclosure:
- NEMA 4X Enclosure
- Supported Protocols:
- None
- Humidity Element:
- None
- CO2 Element:
- None
- Setpoint:
- No Setpoint
- Override:
- No
- Display:
- No Display
