The Dwyer RHPX-3LHAB-00 is a outdoor wall mount humidity and temperature transmitter from the Dwyer Series RHPX, built around a capacitive polymer humidity sensor rated to ±3% RH across 10% to 90% RH at 25°C (77°F). Humidity output is field selectable between 4-20 mA, 0-5 V dc and 0-10 V dc, and an active analog temperature output is available on that same selectable range. Which channels are wired depends on the topology chosen from the four wiring figures in AQ-RHPX-A. A separate 10,000 Ω @ 25°C thermistor type II provides a passive resistive temperature output. Dwyer documents the passive sensor with single 4-20 mA, single voltage and dual voltage wiring; the dual 4-20 mA configuration is shown without it. A factory-installed solar radiation shield over the HDPE filter shades the sensing element for outdoor air reference duty. The housing is UL 94 V-0 rated to IP66 / NEMA Type 4X, and on-board DIP switches select imperial or metric units, voltage or current output, and whether the humidity channel reports relative humidity, dew point, enthalpy or absolute humidity.
- Outdoor humidity and temperature reference, with the solar radiation shield factory installed
- Air economizer sequences using the selectable enthalpy or dew point humidity output
- Controllers needing a transmitted humidity signal and a passive resistive temperature input from one device, wired per Figure 1, 3 or 4 of AQ-RHPX-A
- Plenum-space installations covered by UL 2043
- Dwyer publishes these Series RHPX applications: air economizers, outdoor humidity and temperature reference, pool room humidity monitoring, building energy management systems, commercial HVAC systems, clean rooms, museums and data centers
Key Features
Active and Passive Temperature Paths
The selected 10,000 Ω @ 25°C thermistor type II provides an independent passive resistive temperature signal. AQ-RHPX-A documents the passive sensor alongside single 4-20 mA operation (Figure 1), single voltage output (Figure 3), and dual voltage output carrying RH and active temperature together (Figure 4). The dual 4-20 mA configuration in Figure 2 is documented without a passive temperature sensor. Passive temperature sensors are available on analog models only.
±3% RH Capacitive Polymer Sensor
Humidity sensor accuracy is ±3% at 10% to 90% RH and 25°C (77°F), across a full 0% to 100% measurement range, with 0.1% RH resolution.
Four Selectable Humidity Metrics
DIP switches 4 and 5 set the humidity channel to relative humidity, enthalpy, dew point or absolute humidity. Absolute humidity spans 0 to 50 g/m3, dew point -75°C to 60°C, and enthalpy -40 to 411 kJ/kg.
Field-Selectable Output and Units
DIP switch 1 selects metric or imperial units, switch 2 selects 0-10 V or 0-5 V, and switch 3 selects voltage or 4-20 mA output. Default is imperial units, 4-20 mA, %RH. On-board trimmers allow ±3.5% RH and ±5°F field offset.
UL 2043 Plenum Rated
UL 2043 compliance covers RHPX-XL(H) large wall mount without LCD and solar radiation shield, which includes this model, allowing installation into the plenum space. The unit also carries BTL and CE compliance, and Dwyer qualifies its UL 60335-2-40 listing as meeting UL 60335-2 clause 30.103DV.1 through that same UL 2043 compliance.
Factory-Installed Solar Radiation Shield
The radiation shield ships fitted over the HDPE filter, shading the sensing element from radiant heat so the reading tracks true outdoor air rather than solar gain on the housing. Dwyer still directs that the transmitter be mounted under an eave, shield or otherwise out of the elements and direct sunlight, with the sensor pointing down.
Technical Specifications
| Model / SKU | RHPX-3LHAB-00 |
| Sensor Configuration | H — HDPE filter and solar radiation shield (factory installed) |
| Enclosure Size | L — Large enclosure |
| Humidity Measurement Range | 0% to 100% humidity |
| Humidity Sensor Accuracy | ±3%, at 10% to 90% RH and 25°C (77°F) |
| Humidity Sensor | Capacitive polymer |
| Temperature Measurement Range | -40°C to 60°C (-40°F to 140°F) |
| Humidity Analog Output | 4-20 mA or 0-5 V dc, 0-10 V dc at 5 mA max, field selectable |
| Active Temperature Analog Output | 4-20 mA or 0-5 V dc, 0-10 V dc at 5 mA max, field selectable |
| Active Temperature Accuracy (Solid State Band Gap) | ±0.9°F @ 77°F (±0.5°C @ 25°C) |
| Passive Temperature Sensor | 10,000 Ω @ 25°C thermistor type II (order code B) |
| Passive Temperature Accuracy (Thermistor) | ±0.2°C @ 25°C (±0.36°F @ 77°F), analog models only |
| Power Requirements | 4-20 mA: 10 to 35 Vdc. Voltage output: 15 to 35 Vdc or 15 to 29 Vac |
| Wiring Connection | Removable terminal block, 18 AWG maximum |
| Resolution | Relative humidity 0.1%; temperature 0.1°F/°C; absolute humidity 0.1 g/m3 |
| Additional Calculations | Absolute humidity 0 to 50 g/m3 or 0 to 3000 lb/mmcf; dew point -75°C to 60°C (-102°F to 140°F); enthalpy -40 to 411 kJ/kg or -17 to 177 Btu/lb |
| Operating Temperature Range | -40°C to 60°C (-40°F to 140°F) |
| Storage Temperature | -40°C to 70°C (-40°F to 158°F) |
| Display | None on this model |
| Electrical Entry | 1/2 in NPS thread, cable gland included |
| Enclosure Material | UL 94 V-0 |
| Enclosure Rating | IP66, NEMA Type 4X |
| Product Weight | 1247.4 g (2.75 lb), large housing with radiation shield |
| Compliance | BTL, CE, UL 2043. UL 60335-2-40 per Dwyer footnote: meets UL 60335-2 clause 30.103DV.1 through UL 2043 compliance. |
| Warranty | 5 year limited warranty |
Documentation
Related Products
Frequently Asked Questions
Reading the Dwyer order code left to right: RHPX is the series, 3 is 3% RH accuracy, L is the large enclosure, H is HDPE filter and solar radiation shield (factory installed), A is the selectable analog output, B is the 10,000 Ω @ 25°C thermistor type II passive temperature sensor, and 00 is the cable length option.
No. The two-line alphanumeric display is a separate -LCD option on the Series RHPX order code.
Yes. DIP switches 4 and 5 set the humidity channel output to relative humidity, enthalpy, dew point or absolute humidity. The default setting is %RH.
It depends on the output mode selected. In 4-20 mA mode the transmitter needs 10 to 35 V dc. In voltage output mode it needs 15 to 35 V dc or 15 to 29 V ac. The 4-20 mA models are not designed for AC voltage operation.
Yes. DS-RHPX Rev.1 lists RHPX-XL(H) large wall mount without LCD and solar radiation shield under its UL 2043 compliance footnote, and RHPX-3LHAB-00 falls in that group.
No. On the H configuration the solar radiation shield is factory installed. The separate RHRS six-plate shield is the accessory Dwyer recommends for sintered filter versions installed outdoors.
5 Year Limited Warranty. The Dwyer Series RHPX carries a five year limited warranty as published on the Dwyer Series RHPX catalog page. Warranty and return handling follow the Terms and Conditions of Sale published by Dwyer Instruments, LLC. Contact customer service for a Return Materials Authorization (RMA) number before shipping any product back for repair, and include a brief description of the problem plus any application notes.
The Series RHPX requires no routine maintenance, is not field serviceable, and cannot be repaired. Field repair should not be attempted and may void the warranty.
ZOT Supply is an authorized DwyerOmega distributor. Warranty support is handled through ZOT Supply at sales@zotsupply.com or 855-825-2811.
- Sensor Type:
- Outside Air
- Humidity Element:
- 3%
- Series:
- RHPX
- Humidity Output:
- 4–20 mA (loop output)
- Humidity Output:
- 0–5V or 0–10V (jumper-selectable)
- Supported Protocols:
- None (analog)
- Temperature Element:
- 10K Type II
- Display:
- No Display
- Enclosure:
- NEMA 4X Enclosure
- Enclosure:
- Sun Shield
- CO2 Element:
- None
