PDWA Medium ESP Ducted
The Polar Air PDWA medium ESP ducted, hydronic fan coil delivers powerful heating and cooling up to 23 kW in a compact, concealed design.
It features interchangeable water coil connections for installation and reduced dimensions, making it suitable for small ceiling voids and challenging spaces.
Designed for external static pressures up to 130 Pa (0.5 in.wg), with a recommended operating point of 75 Pa (0.3 in.wg), the PDWA is ideal where ductwork resistance is minimal.
It is suited for residential, commercial, and healthcare applications, such as condos, hospitals, supermarkets, and gyms.
10 sizes available · 2-pipe or 4-pipe models · 3R, 4R, 6R, 3R+1 or 4R+2 configurations
Advantages
Heating & Cooling
Capacities up to 23 kW provides powerful cooling in summer and reliable heating in winter, for year-round comfort.
Ideal for various applications, including residential, healthcare and commercial buildings, including apartments, hospitals, and supermarkets.
Adaptable Design
Interchangeable coil connections simplify installation, whilst compact dimensions fit easily into concealed or challenging spaces.
Plus an optional G4 (MERV 8) filter upgrade captures finer particles, supporting cleaner air quality in environments that need it like healthcare.
Multiple rows: 3R · 3R+1 · 3R+2 · 4R · 4R+2 · 6R
Multiple coil row configurations provide greater surface area for heat transfer, delivering higher efficiency and more cooling and heating capacity.
The added surface also improves latent capacity for better humidity control and more consistent comfort across varying load conditions.
ESP Conditions
Medium external static pressures from 15 - 130 Pa (0.05 - 0.5 in.wg), recommended 75 Pa (0.3 in.wg).
Suitable for projects with short duct runs and limited bends, where excessive resistance would reduce airflow.
Models
Includes both a 2-pipe and 4-pipe model, and available in 10 sizes to suit complex applications like hospitals.
The 4-pipe allows heating in one area and cooling in another simultaneously, ideal for buildings with varied thermal loads like north/south-facing zones or occupancy.
Installation & Maintenance
Supplied ready to install, cutting time and cost, with external painted steel drain pan, 5 mm (0.2”) NBR insulation, manual air vent + water purge valve and G2 (MERV 4) filter.
Capacities
Metric
🍃 Airflow: 225 – 3877 m3/h
❄️ Cooling: 1.6 – 23.6 kW
☀️ Heating: 1.2 – 23.2 kW
🔊 Sound pressure: from 39 dBA*
Imperial
🍃 Airflow: 133 – 2365 CFM
❄️ Cooling: 4433 – 62824 BTU/Hr | 0.4 – 5.2 Ton
☀️ Heating: 4708 – 97663 BTU/Hr | 0.4 – 8.1 Ton
🔊 Sound pressure: from 39 dBA*
* Sound pressure level measured at 1 m distance in a reverberation test room with the minimum volume of 200 m3.
- Compatible with renewable energy systems – works with solar thermal collectors, heat pumps, and other low-temperature sources for higher energy savings.
- Durable coil design – copper tubes and headers mechanically expanded into corrugated aluminum fins, pressure-tested up to 35 bar with a 16-bar operating limit.
- 0–10 VDC EC motor – delivers up to 30% energy savings compared to AC motors, with smoother speed control, quieter operation, and lower running costs.
- Manual air vent + water purge valve – enables quick and efficient system bleeding for hassle-free maintenance.
- External drain pan – in painted steel to safely collect and channel condensate, protecting interiors from leaks, water damage, and moisture issues.
- 5 mm (0.2”) NBR insulation – minimizes energy loss and prevents condensation for long-lasting efficiency.
- G2 (MERV 4) filter – captures dust and larger particles to improve indoor air quality and protect the coil.
- I-Type Controllers: Infrared Handset or Wired Wallpad
- Valves: HYDRO+ VALVE Kit with 2/3-way body valve, on-off/modulating actuator (24V or 110-240V), BSPT or NPT connectors, connection piping kit, 2x shut-off valves, strainer and manual balancing valve
- Condensate pump: Sauermann with float switch
- Electric heater: up to 6 kW
- Insulation: 10 mm (0.3”), 15 mm (0.6”) or 25 mm (1”) NBR
- Filter: G4 (MERV 8)
- Integrated transformer: converts from 230V to 24V for valve and thermostat compatibility
- Disconnect switch: integrated in control box
- Customization: available upon request (minimum order quantities apply)
Polar Air Control Logic
Polar Air fan coil units provide exceptional control flexibility to meet various application needs. Choose between two types of PCBs.
I-Type Control
Exclusively developed by Polar Air for intelligent control that includes our ADBS technology for ΔT management and group control. Configuration for 2- and 4-pipe models.
Available through ModBus, or compatible with Polar Air Wired Wallpad or Infrared Handset.
24/7 programming
Auto & 3-Speed functions
Sleep function
Auto-Restart function
Dehumidification mode
Adjustable swing louver positioning
Condensate drain pump control
Error diagnostics on unit LED display or Wired Wallpad
Valve control
Dry contact for On/Off applications
Electric heater control
2 x 24V auxiliary contacts for ERVS or dampers
Building Management Systems (BMS) compatible via Modbus
Auto-Dynamic Balancing System with constant ΔT management
255 units group control via ModBus
32 units group control via Wired Wallpad
I-Type Control
Exclusively developed by Polar Air for intelligent control that includes our ADBS technology for ΔT management and group control. Configuration for 2- and 4-pipe models.
Available through ModBus, or compatible with Polar Air Wired Wallpad or Infrared Handset.
24/7 programming
Auto & 3-Speed functions
Sleep function
Auto-Restart function
Dehumidification mode
Adjustable swing louver positioning
Condensate drain pump control
Error diagnostics on unit LED display or Wired Wallpad
Valve control
Dry contact for On/Off applications
Electric heater control
2 x 24V auxiliary contacts for ERVS or dampers
Building Management Systems (BMS) compatible via Modbus
Auto-Dynamic Balancing System with constant ΔT management
255 units group control via ModBus
32 units group control via Wired Wallpad
W-Type Control
Simple yet flexible functionality that is easy to use, allowing for limited LED diagnostics and RPM configuration. Available for 2- and 4-pipe models.
Compatible with external thermostats from a variety of manufacturers.
Choose your own external thermostats
Configure the motor RPMs to your choice
Contact alarm for condensate drain pump and motor
Limited error diagnostics on unit LED display or Wired Wallpad
Project applications & references
Explore recommended applications and recent projects where it’s been successfully installed.
Residential
Houses · Apartments/Condos · Assisted Living · Student Accommodation
Healthcare
Hospitals · Clinics · Nursing Homes · Treatment Centers · Laboratories · Morgues
Commercial
Supermarkets · Stores · Shopping Malls · Gyms/Sports Facilities · Museums/Theaters · Airports/Transport Terminals
Hospitality
Hotel Bedrooms · Hotel Reception Areas · Banquet Halls · Restaurants · Cafes
W Residences
2016
United Arab Emirates
New construction · EC motor · luxury apartments/villas
Parks & Yards
2024
Canada
British Columbia
New construction · EC motor · condo/apartment blocks
200 Elgin Street
2025
Canada
Ontario
Retrofit · EC motor · W-Type control · condo/apartment blocks
Bolnica Sisak Hospital
2024
Croatia
Retrofit · EC motor · hospital wards & public areas
White Square Tower
2016
Qatar
Travis Park
2024
United States
Texas
Frasers Student Accommodation
2017
Australia
Private Residence Ardglass
2025
United Kingdom
New construction · EC motor · single private home
Hilton Hotel
2017
South Africa
Luna Vista Toronto
2025
Canada
Ontario
Windsor Retirement Residence
2016
Canada
Ontario
Polycorp Residential
2017
Canada
Nova Scotia
Serena Del Mar (Cavana)
2024
Colombia
New construction · EC motor · district cooling · condo/apartment blocks
Al Reziza Tower
2015
Saudi Arabia
New construction · EC motor · mixed use commercial spaces
Dalhousie University
2017
Canada
Nova Scotia
Lesedi Hospital
2017
South Africa
Knox Private Hospital
2011
Australia
Higher Education Building
2024
Ireland
Our PASELECT Software is specifically designed to help users choose the most suitable Polar Air fan coils for any project.
Downloads: IOMs, Revits & Guide Specs
Access product resources including installation and operation manuals (IOMs), Revit files, and guide specifications.
Revit Files: PDWA_Medium ESP Ducted_4-pipe
|Size: 24 MB - ENRevit Files: PDWA_Medium ESP Ducted_2-pipe
|Size: 9 MB - ENIOM: PDWA Medium ESP Ducted_METRIC_EC Motor
|Size: 3 MB - EN
Revit Files: PDWA_Medium ESP Ducted_4-pipe
|Size: 24 MB - ENRevit Files: PDWA_Medium ESP Ducted_2-pipe
|Size: 9 MB - ENIOM: PDWA Medium ESP Ducted_IMPERIAL_EC Motor
|Size: 4 MB - ENOur trusted network of authorized representatives ensures you receive exceptional customer service and product availability worldwide.
FAQs: medium ESP ducted
What row configurations are available for the PDWA Ducted?
The PDWA is available in 3R, 3R+1, 3R+2, 4R, 4R+2, and 6R coil configurations.
Increasing the number of rows expands coil surface area, which improves heat transfer and allows the unit to achieve higher capacities in the same footprint. More rows also enhance latent performance, providing better humidity control in demanding climates.
For projects using low-temperature heat sources such as heat pumps or solar thermal systems, additional coil rows improve efficiency by increasing the contact time between air and water, ensuring effective output at lower water temperatures.
What ESP capacity does the PDWA have?
PDWA Medium ESP Capacities:
Total: 15 – 130 Pa (0.06 – 0.52 in.wg).
Recommended: 75 Pa (0.3 in.wg)
What does ESP mean?
ESP stands for External Static Pressure. A ducted ESP fan coil is designed to handle specific levels of resistance in the ductwork, ensuring efficient airflow and optimal performance.
For example, the PDWA Medium ESP Ducted is designed explicitly for medium cooling capacities at lower external static pressures. It makes the PDWA suitable for installations with short runs and limited bends, where airflow resistance is minimal.
What happens if I oversize or undersize ESP?
External static pressure must be matched to the resistance created by ductwork, grilles, filters, and fittings. If ESP is oversized (for example, using a high ESP unit on a short, straight duct run), the fan will push more air than required. This can cause excess noise, drafts at supply outlets, and wasted fan energy. In some cases, it may also lead to premature wear of system components.
If ESP is undersized (for example, choosing a low ESP unit for a layout with long ducts and multiple bends), the fan may not overcome the resistance in the system. Airflow will drop, rooms at the end of the duct may not receive enough conditioned air, and overall cooling or heating performance will suffer. The result is uneven comfort and inefficient operation. Correctly selecting ESP ensures the fan operates within its designed range, balancing airflow delivery, noise, and energy use.
Can medium ESP fan coils work with variable airflow or zoning systems?
Yes, medium ESP fan coils can be integrated into variable airflow or zoning systems if the total duct resistance remains within their operating range, typically 50–130 Pa (0.2–0.5 in.wg). These units are often specified in projects where one fan coil serves several rooms, with zone dampers used to balance distribution.
In real-world conditions, zoning adds pressure as dampers close and open. Medium ESP provides enough fan power to handle moderate changes without the energy consumption or noise of high ESP units. However, in systems with extensive zoning, complex ductwork, or high resistance from filters and accessories, a high ESP fan coil like the Polar Air PDWC may be more appropriate.
When should I choose low vs medium vs high ESP ducted fan coils?
The choice between low, medium, and high ESP ducted fan coils depends on duct design, building type, and required airflow.
Low ESP (0–50 Pa / 0–0.2 in.wg): Best for short, simple duct runs or direct discharge into a room. Common in small apartments, hotel rooms, or spaces with no complex duct layout.
Appropriate Polar Air model: PDWSL Slim.
Medium ESP (50–130 Pa / 0.2–0.5 in.wg): Suitable for moderate ductwork with a few bends or short runs serving multiple rooms. Typical in residential apartments, small offices, or clinics, where ducts are concealed in ceilings.
Appropriate Polar Air model: PDWA Medium.
High ESP (>130 Pa / >0.5 in.wg): Required for large commercial or institutional projects with long duct runs, multiple fittings, higher filter resistance, or when air must be delivered across multiple zones. Examples include shopping malls, hospitals, and airports.
Appropriate Polar Air model: PDWC High, PDWD Double Skin, HAHU-B or VAHU.
A simple rule of thumb: the more complex or extensive the ductwork, the higher the ESP rating you’ll need. Oversizing wastes energy and adds noise, while undersizing compromises airflow and comfort.
Can medium ESP fan coils be used with low-temperature heat sources?
Yes. Medium ESP fan coils are commonly used with low-temperature heat sources, including heat pumps, district energy systems, and solar thermal collectors. Unlike conventional boiler systems, which may supply hot water at 70–80°C, low-temperature sources often operate at 35–55°C.
To maintain output at these lower temperatures, fan coils often require additional coil rows or larger surface areas. More rows increase air-to-water contact time, improving heat transfer and allowing the unit to provide adequate heating and cooling even when supply water temperatures are lower. This makes medium ESP fan coils well-suited to modern energy-efficient systems, where lower supply temperatures reduce energy consumption and align with building decarbonization goals.
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