The BAPI BA/1K[3W]-I-2"-NB-18" is an immersion temperature sensor with a 1000 Ohm Platinum RTD (385 Curve) (3-Wire RTD Configuration (lead-resistance compensation)) 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 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. Lead wire is built to a custom 18" length.
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 No Box (Lead Wire Direct) enclosure (No enclosure (probe-only), N/A (probe and lead wire only)) 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 (1000 Ohm Platinum RTD (385 Curve) (3-Wire RTD Configuration (lead-resistance compensation))). 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
1000 Ohm Platinum RTD (385 Curve) (3-Wire RTD Configuration (lead-resistance compensation)) 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.
Three-wire connection compensates for lead-resistance error on long cable runs (recommended for runs over 100 feet). The third wire lets the BAS measure and subtract the lead-wire resistance from the reading.
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.
N/A (probe and lead wire only). No enclosure - probe with direct lead wire exit. Use when mounting inside a customer-supplied enclosure or junction box.
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/1K[3W]-I-2"-NB-18" |
| Series | BAPI Immersion w/ Nylon Fitting (B40/B41) |
| Sensor Type | Passive Resistance Sensor (unpowered) |
| Temperature Element | 1000 Ohm Platinum RTD (385 Curve) (3-Wire RTD Configuration (lead-resistance compensation)) |
| Nominal Resistance | 1000 Ohm at 0 degC |
| Sensitivity | 3.85 Ohm/degC (385 curve, DIN43760) |
| 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 NPSM Plastic (Nylon) |
| Lead Wire | 22 AWG Stranded, Etched Teflon, Plenum Rated |
| Lead Wire Length | 18" |
| Wiring Option | Flying Leads |
| Enclosure Model | No Box (Lead Wire Direct) |
| Enclosure Rating | No enclosure (probe-only) |
| Enclosure Material | N/A (probe and lead wire only) |
| Enclosure Dimensions (H x W x D) | Probe only - no enclosure |
| Enclosure Ambient Temperature | Per probe spec (-40 to 221 degF / -40 to 105 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 (2 inch (51 mm)).
This sensor is a passive 1000 Ohm Platinum RTD (385 Curve) (3-Wire RTD Configuration (lead-resistance compensation)). 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 No Box (Lead Wire Direct) (No enclosure (probe-only), N/A (probe and lead wire only)). No enclosure - probe with direct lead wire exit. Use when mounting inside a customer-supplied enclosure or junction box.
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:
- 1000 Ohm Platinum RTD (385 Curve)
- Output Signal:
- Resistance (to BAS analog input)
- Probe Length:
- 2 inch (51 mm)
- Probe Fitting:
- Nylon (1/2 inch NPSM Plastic)
- Calibrated Range:
- -40 to 221 degF (probe operating range, passive)
- Enclosure:
- No Box (Lead Wire Direct)
- Mount Position:
- N/A (Probe Only)
- Enclosure Rating:
- No enclosure (probe-only)
- Wiring Configuration:
- Flying Leads
- Country of Origin:
- Made in USA