The BAPI BA/20K-I-8"-BB2 is an immersion temperature sensor with a 20K NTC Thermistor sensing element, potted in a 8 inch (203 mm) long, 0.25 inch OD 304 stainless steel probe with thermally-conductive compound. The probe threads into a thermowell via a 1/2 inch NPSM nylon 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 2 enclosure (NEMA 4 / IP66, UV-Resistant Polycarbonate, UL94 V-0) and wired for Flying Leads. 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 8 inch (203 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.
The plastic NPSM fitting allows the probe to slide up to 1.6 inch inside the enclosure as the unit is hand-threaded onto the thermowell - probe tip self-seats against the thermowell bottom on tightening. Hand-tight only; no thread sealant required on this side.
UV-Resistant Polycarbonate, UL94 V-0. Compact NEMA 4 polycarbonate enclosure with smaller footprint than BB.
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-8"-BB2 |
| Series | BAPI Immersion w/ Nylon Fitting (B40/B41) |
| 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 | 8 inch (203 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 NPSM Plastic (Nylon) |
| Lead Wire | 22 AWG Stranded, Etched Teflon, Plenum Rated |
| Wiring Option | Flying Leads |
| Enclosure Model | BAPI-Box 2 |
| Enclosure Rating | NEMA 4 / IP66 |
| Enclosure Material | UV-Resistant Polycarbonate, UL94 V-0 |
| Enclosure Dimensions (H x W x D) | 4.9 x 2.8 x 2.35 inch (125 x 71.6 x 60 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 NPSM Plastic (Nylon), hand-tightened) |
| 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 (8 inch (203 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 2 (NEMA 4 / IP66, UV-Resistant Polycarbonate, UL94 V-0). Compact NEMA 4 polycarbonate enclosure with smaller footprint than BB.
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 Nylon Fitting Sensor
- Sensor Type:
- Passive Resistance Sensor
- Temperature Element:
- 20K NTC Thermistor
- Output Signal:
- Resistance (to BAS analog input)
- Probe Length:
- 8 inch (203 mm)
- Probe Fitting:
- Nylon (1/2 inch NPSM Plastic)
- Calibrated Range:
- -40 to 221 degF (probe operating range, passive)
- Enclosure:
- BAPI-Box 2
- Enclosure Rating:
- NEMA 4 / IP66
- Wiring Configuration:
- Flying Leads
- Country of Origin:
- Made in USA