The Dwyer RHPX-3SDAA-00 is a duct 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 III 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. The plenum plastic probe carries a hydrophobic filter for duct air streams. 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.
- Duct-mounted humidity and temperature measurement, installed per the duct mounting procedure in AQ-RHPX-A
- 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 III 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-XS(D,E)-XX-X plastic probe duct mount without LCD, 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.
Serviceable Installation Details
Removable terminal block accepts up to 18 AWG wire, the lid stays attached, and a 1/2 in NPS electrical entry ships with a cable gland.
Technical Specifications
| Model / SKU | RHPX-3SDAA-00 |
| Sensor Configuration | D — Duct mount with plenum plastic probe and hydrophobic filter |
| Enclosure Size | S — Small 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 III (order code A) |
| 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 |
| Duct Installation | 1 in diameter duct hole; four #8 x 1/2 in pan head sheet metal screws |
| Product Weight | 198.4 g (0.44 lb), duct configuration |
| 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, S is the small enclosure, D is Duct mount with plenum plastic probe and hydrophobic filter, A is the selectable analog output, A is the 10,000 Ω @ 25°C thermistor type III 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-XS(D,E)-XX-X plastic probe duct mount without LCD under its UL 2043 compliance footnote, and RHPX-3SDAA-00 falls in that group.
No. Dwyer states 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.
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:
- Duct
- 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 III
- Display:
- No Display
- Enclosure:
- NEMA 4X Enclosure
- CO2 Element:
- None
- Material:
- Plastic
