The BAPI BA/20K-I-2"-SS-BBXO is an immersion temperature sensor with a 20K NTC Thermistor sensing element, potted in a 2 inch (51 mm) long, 0.25 inch OD 304 stainless steel probe with thermally-conductive compound. The probe threads into a thermowell via a Stainless Steel double-threaded fitting; on hand-tightening the probe slides up to 1.6 inch inside the enclosure body so the tip seats firmly against the thermowell bottom, giving solid thermal contact regardless of thermowell depth tolerance.
The sensor outputs resistance directly to the BAS analog input (no powered signal conditioning). The BAS converts resistance to temperature using a sensor-specific R/T table programmed in the controller. The unit is housed in the BAPI-Box Crossover (Outside Mount) enclosure (NEMA 1 / IP10 (IP44 with knockout plug), Polycarbonate UL94 V-0 & Nylon UL94 HB) and wired for Flying Leads. The Outside-Mount (O) configuration orients the mounting flange on the OUTSIDE of the enclosure body, which suits applications where the enclosure must be flush against a panel or wall and the probe exits from the rear. Made in USA by BAPI of Gays Mills, Wisconsin.
Water-pipe, hydronic-loop, cooling-tower-sump, and tank temperature measurement on BAS systems that accept resistance-input directly (20K NTC Thermistor). The 2 inch (51 mm) probe fits a matching BAPI thermowell of the same length; for a typical 8 inch insulated pipe, a 4 inch probe in a 4 inch thermowell reaches the centerline (best-case thermal contact with the flowing media).
Key Features
20K NTC Thermistor potted inside a 0.25 inch OD 304 stainless steel probe with thermally-conductive compound. Etched Teflon leadwire is plenum-rated. The double encapsulation keeps the sensor watertight under 100% RH non-condensing service.
1/2 inch NPT stainless steel threads provide a metal-to-metal seal and resist corrosion in process fluids. Use thread sealant per the application.
Polycarbonate UL94 V-0 & Nylon UL94 HB. Hinged-cover polycarbonate enclosure with optional pierceable knockout plug for IP44.
Mounting flange located on the OUTSIDE of the enclosure body - the probe exits from the rear and the enclosure mounts flush to a panel or wall. Useful in tight wiring closets and slim-profile installations.
Designed and manufactured by Building Automation Products, Inc. at 750 North Royal Avenue, Gays Mills, Wisconsin. RoHS / CE compliant.
Technical Specifications
| Specification | Value |
|---|---|
| Manufacturer | Building Automation Products, Inc. (BAPI) |
| Manufacturer Part Number | BA/20K-I-2"-SS-BBXO |
| Series | BAPI Immersion w/ Stainless Steel Fitting |
| Sensor Type | Passive Resistance Sensor (unpowered) |
| Temperature Element | 20K NTC Thermistor |
| Nominal Resistance | 20 kOhm at 25 degC |
| Sensitivity | Non-linear (R/T table required) |
| Output Type | Resistance (to controller analog input, no polarity) |
| Probe Length | 2 inch (51 mm) |
| Probe Material | 304 Stainless Steel, 0.25 inch outer diameter |
| Probe Construction | Double-encapsulated sensing element with thermally-conductive potting |
| Process Fitting | 1/2 inch NPT Stainless Steel |
| Lead Wire | 22 AWG Stranded, Etched Teflon, Plenum Rated |
| Wiring Option | Flying Leads |
| Enclosure Model | BAPI-Box Crossover (Outside Mount) |
| Enclosure Rating | NEMA 1 / IP10 (IP44 with knockout plug) |
| Enclosure Material | Polycarbonate UL94 V-0 & Nylon UL94 HB |
| Enclosure Dimensions (H x W x D) | 3.1 x 2.2 x 1.9 inch (79 x 56 x 49 mm) |
| Enclosure Ambient Temperature | -40 to 185 degF (-40 to 85 degC) |
| Ambient Humidity | 0 to 100% RH, non-condensing |
| Mounting Method | Thermowell insertion (1/2 inch NPT Stainless Steel, hand-tightened) |
| Mount Configuration | Outside-Mount (mounting flange on exterior of enclosure) |
| Agency Compliance | RoHS, CE (where applicable) |
| Country of Origin | Made in USA (Gays Mills, WI) |
Documentation
Frequently Asked Questions
BAPI strongly recommends installing this sensor inside a matching thermowell rather than direct-immersion. A thermowell lets the sensor be removed and serviced without draining or depressurizing the pipe / tank, and protects the probe from corrosion or mechanical damage. Match the thermowell length to the probe length (2 inch (51 mm)).
This sensor is a passive 20K NTC Thermistor. The BAS controller needs the matching R/T (resistance / temperature) curve programmed in its analog-input setup - typically selectable by manufacturer-specific table name. The full R/T table is at bapihvac.com under Resources -> Sensor Specs.
This SKU uses the BAPI-Box Crossover (Outside Mount) (NEMA 1 / IP10 (IP44 with knockout plug), Polycarbonate UL94 V-0 & Nylon UL94 HB). Hinged-cover polycarbonate enclosure with optional pierceable knockout plug for IP44.
The SS fitting is double-threaded and seals metal-to-metal with the thermowell - more robust than the nylon NPSM fitting for high-pressure water service or applications where chemical compatibility, vibration, or mechanical abuse could fatigue a plastic fitting. The SS variant uses 1/2 inch NPT threads (standard tapered) which seat with thread sealant; the nylon variant uses 1/2 inch NPSM (straight) threads and is hand-tight only with no sealant.
The mounting flange is relocated to the OUTSIDE of the enclosure body (instead of the standard inside-mount configuration). The probe exits from the rear of the enclosure and the enclosure mounts flush against a panel or wall. Useful in tight wiring closets, slim panel installations, or applications where the enclosure must be flush with the mounting surface.
Yes. BAPI Immersion sensors and transmitters are designed and manufactured by Building Automation Products, Inc. at 750 North Royal Avenue, Gays Mills, Wisconsin (USA).
- Brand:
- BAPI
- Series:
- Immersion SS Double-Threaded Sensor
- Sensor Type:
- Passive Resistance Sensor
- Temperature Element:
- 20K NTC Thermistor
- Output Signal:
- Resistance (to BAS analog input)
- Probe Length:
- 2 inch (51 mm)
- Probe Fitting:
- Stainless Steel (1/2 inch NPT, Double-Threaded)
- Calibrated Range:
- -40 to 221 degF (probe operating range, passive)
- Enclosure:
- BAPI-Box Crossover
- Mount Position:
- Outside Mount
- Enclosure Rating:
- NEMA 1 / IP10 (IP44 with knockout plug)
- Wiring Configuration:
- Flying Leads
- Country of Origin:
- Made in USA