Pneumatic Temperature Sensors

Pneumatic temperature sensors are proportional-type devices that convert measured air or fluid temperature into a 3 to 15 psi output signal, used to drive pneumatic valve and damper actuators in commercial and institutional HVAC systems. Every Honeywell LP914A and LP915A pneumatic temperature sensor in the SupplyHouse lineup operates on a direct-acting, one-pipe design compatible with RP908 and RP920 pneumatic controllers. The LP914A series covers rod and tube insertion elements in lengths from 7 inches to 27 inches across multiple temperature ranges. The LP915A1044 steps up to a liquid-filled, 18-1/2-foot averaging element for large duct cross-sections where a single-point reading won't reflect what's actually happening in the airstream. For any building still running pneumatic controls, keeping the right sensor in the right location is what keeps the rest of the system honest.

KEY SUBCATEGORIES / PRODUCT TYPES

The LP914A1045 is a one-pipe, direct-acting rod and tube sensor with a 7-inch element covering -40 to 160°F, designed for duct, well, or through-the-wall mounting. LP914A1045 draws 0.019 scfm (540 sccm) from an 18 psi supply and produces a proportional output across the 3 to 15 psi range. Corrosion-resistant construction and push-on barb air connections for 5/32-inch (4 mm) and 1/4-inch (6 mm) O.D. tubing keep installation clean on existing pneumatic loops. The LP914A1045 is the right call when the target temperature range falls in mixed-air or return-air territory and the duct or well opening accommodates a short insertion element.

The LP914A1060 shares the 7-inch rod and tube form factor and -40 to 160°F range, with well-mount orientation as its primary application. LP914A1060 specs mirror the LP914A1045 at the critical parameters: 18 psi supply, 3 to 15 psi output, 25 psi max safe operating pressure, and a max operating temperature of 265°F. For jobs where a pipe well is already in place and the element needs to drop in without a new duct penetration, the LP914A1060 is a direct fit.

The LP914A1052 covers the same 7-inch, well-mount configuration as the LP914A1060 but runs a 40 to 240°F temperature range. LP914A1052 is the well-mount sensor to reach for on hot water system monitoring or any application where the measured fluid temperature climbs above the 160°F ceiling of the standard range sensors. The extended range doesn't change the output signal or connection type; it's still 3 to 15 psi out, push-on barb connections, compatible with RP908/RP920 controllers.

The LP914A1003 is a 15-inch rod and tube sensor covering -40 to 160°F for duct, well, or through-the-wall mounting. A longer element means more of the insertion reaches into the active airstream, which matters in larger duct cross-sections where a 7-inch element might not clear the boundary layer near the duct wall. LP914A1003 carries the same shared specs as the rest of the LP914A series: 18 psi supply, 3 to 15 psi output, 0.019 scfm airflow usage, corrosion-resistant construction.

The LP914A1029 matches the 15-inch element length of the LP914A1003 but covers 40 to 240°F, making LP914A1029 the hot-side replacement for duct or well applications where supply air temperatures run well above standard mixed-air conditions. When the system sees pre-heat coils, steam converters, or high-temperature hydronic supply loops, the 40 to 240°F range keeps the sensor working in its calibrated band rather than pegging at the top of a narrower scale.

The LP914A1144 steps up to a 25-inch rod and tube element with a tighter 25 to 125°F range, duct-mount only. LP914A1144 is built for applications where the sensing range matches a narrow, well-defined operating band and a longer element is needed to reach the center of a deeper duct. The narrower calibrated span typically means finer proportional resolution across that range, which is worth specifying when control precision across a moderate temperature band is the priority.

The LP914A1011 runs the longest rod and tube element in the LP914A series at 27 inches, covering -40 to 160°F for duct, well, or through-the-wall mounting. LP914A1011 is the sensor for large commercial air handlers where duct width demands a long insertion to get clear of the wall boundary layer. Same output signal, same connection spec, same controller compatibility as every other LP914A. Just more element to work with.

The LP915A1044 is a liquid-filled, averaging-element pneumatic temperature sensor with an 18-1/2-foot flexible element covering 0 to 200°F, duct-mount. Where rod and tube sensors read a single point, the LP915A1044 averages temperature across the full element length, which can be formed into configurations that sweep the active duct cross-section. LP915A1044 is a one-pipe, direct-acting sensor used with RP908 and RP920 controllers, and continuous temperature indication is available via a receiver gauge. For mixed-air sensing in large air handlers or any application where stratification makes point readings unreliable, the LP915A1044 is the appropriate

BUYING GUIDE / HOW TO CHOOSE

Sizing a pneumatic temperature sensor starts with element length and mounting type, because those two variables determine whether the sensor actually reads what's in the airstream rather than what's near the duct wall. In duct applications, the element needs to reach the active airflow. A 7-inch element like the LP914A1045 or LP914A1060 works in small to medium ducts. Larger duct cross-sections call for 15-inch options like the LP914A1003 and LP914A1029, or the 25-inch LP914A1144 for the deepest penetrations. Pipe well applications match element length to the installed well depth.

Temperature range selection is the next variable. Pneumatic temperature sensors perform best when the calibrated range closely matches the expected operating band. For mixed-air and return-air sensing, the -40 to 160°F sensors (LP914A1045, LP914A1060, LP914A1003, LP914A1011) cover most applications. For hot water or high-temperature supply air, the 40 to 240°F options (LP914A1052, LP914A1029) are the correct choice. The LP914A1144's 25 to 125°F calibrated range targets a tighter operating band and typically delivers finer proportional resolution within it. The LP915A1044 covers 0 to 200°F across its full averaging element.

Duct stratification is the case for choosing the LP915A1044 liquid-filled averaging sensor over any rod and tube option. Mixed-air plenums, outside air intakes, and large supply duct cross-sections can show temperature variation of 15 to 20 degrees across the duct face. A single-point rod and tube sensor reading from one location can't represent average conditions accurately enough to hold setpoint reliably. The LP915A1044's 18-1/2-foot element, configured to sweep the duct face, measures average conditions directly.

All LP914A and LP915A sensors are one-pipe, direct-acting, and designed for use with RP908 and RP920 pneumatic controllers. Confirm controller compatibility before specifying. Air connections accept push-on barb fittings for 5/32-inch (4 mm) and 1/4-inch (6 mm) O.D. tubing. Confirm tubing O.D. in the field before ordering to avoid a mismatch at connection. Supply pressure for all LP914A sensors is 18 psi, with a 25 psi maximum safe operating pressure. Standard output is 3 to 15 psi across the calibrated temperature range.

FAQs

What's the difference between the LP914A and LP915A pneumatic temperature sensors?

The difference between the LP914A and LP915A pneumatic temperature sensors is element type and sensing method. LP914A sensors use a rod and tube insertion element that reads temperature at a single point. The LP915A1044 uses a liquid-filled, 18-1/2-foot flexible element that can be configured across a duct cross-section to measure average temperature rather than a single-point value. Both are one-pipe, direct-acting sensors compatible with RP908 and RP920 controllers and produce a 3 to 15 psi output signal, but the LP915A1044 is the correct choice when mixed-air stratification or large duct cross-sections make point sensing unreliable.

Which LP914A sensor should be used for hot water system or high-temperature supply air applications?

The LP914A sensors rated for 40 to 240°F are the appropriate choice for hot water system monitoring or high-temperature supply air applications. LP914A1052 covers 40 to 240°F with a 7-inch well-mount element, and LP914A1029 covers the same 40 to 240°F range with a 15-inch element for duct or well mounting. Using a sensor calibrated for -40 to 160°F in a 40 to 240°F application can result in the output signal running pegged at the top of its range, giving the controller no useful proportional signal to work with.

What element length is needed for pneumatic temperature sensor duct applications?

Element length selection for duct applications depends on duct width and where the active airstream sits within the duct cross-section. A 7-inch element (LP914A1045, LP914A1060, LP914A1052) works for smaller ducts or applications where the element can reach the center of the airflow. Larger ducts call for the 15-inch options (LP914A1003, LP914A1029) or the 25-inch LP914A1144, which reaches deeper into large commercial duct cross-sections. When stratification across the full duct face is a concern, the LP915A1044's 18-1/2-foot liquid-filled averaging element is the appropriate tool rather than any single-point insertion sensor.

Are Honeywell LP914A pneumatic temperature sensors compatible with non-Honeywell pneumatic controllers?

Compatibility between Honeywell LP914A pneumatic temperature sensors and non-Honeywell controllers depends on output signal matching, pipe configuration, and controller-specific calibration requirements. LP914A sensors are specified for use with Honeywell RP908 and RP920 pneumatic controllers, and Honeywell engineering documentation is the authoritative source for any cross-brand pairing. LP914A sensors produce a standard 3 to 15 psi output from an 18 psi supply, which is a widely used pneumatic control signal range, but verifying compatibility against the specific controller manufacturer's documentation is the correct approach before substituting sensors on a running system.

What supply pressure and output range do Honeywell LP914A pneumatic temperature sensors operate at?

Honeywell LP914A pneumatic temperature sensors operate from an 18 psi supply pressure and produce a proportional output signal in the 3 to 15 psi range across their calibrated temperature span. LP914A sensors have a maximum safe operating pressure of 25 psi and draw 0.019 scfm (540 sccm) of air under normal operating conditions. Air connections on all LP914A sensors accept push-on barb fittings sized for 5/32-inch (4 mm) and 1/4-inch (6 mm) O.D. tubing.