Controller
C1050
Program
Water Loop
Supply
24 VAC, Class 2
Outputs
4 DO / 1 AO
Protocol
Modbus RTU (RS485)
Panel
NEMA 1, UL508A
Overview
The Prolon PL-PN1-4Q is a pre-wired, UL508A certified NEMA 1 control panel built with one Prolon C1050 controller running the Water Loop Controller program, which controls a water loop system comprised of a boiler and a water tower with an internal pump. Isolation relays on all digital outputs, overcurrent fuse protection and clearly marked terminal blocks come factory wired.
Program strategies include bypass valve control, cooling tower damper control and spray pump and cooling tower staging. The panel contains 1 Modbus RTU (RS485) node and runs stand-alone or on a Prolon network of up to 127 nodes.
Specifications per Prolon Pre-Wired One Controller Panel datasheet PL-DATA-PANEL1CON-EN-V1; Prolon PL-C1050-WLC Controller datasheet REV 7.3.1 / PL-DATA-C1050WLC-C/F-EN; Prolon C1050 Water Loop Controller Hardware Guide REV 7.3.2; Prolon One Controller Panel product page (proloncontrols.com) retrieved 2026-09-22. Reviewed September 2026.
Best For
- Water loops served by a boiler and a water tower
- Cooling towers with a spray pump and two tower stages
- Loops that divert return water through a bypass valve
Warranty
For warranty coverage on this Prolon panel, contact ZOT Supply at sales@zotsupply.com or 855-825-2811.
Key Features
Heat and reject on one loop
Output 1 drives the boiler, and outputs 2 to 5 open the tower damper, run the spray pump and stage the cooling tower.
17A isolation relays
Every digital output is isolated by a relay rated 17A @ 277 VAC built into the panel (C1050 = 4), and the controller outputs are protected by resettable fuses.
Fused, pre-wired NEMA 1 panel
Clearly marked terminal blocks, wire management channels and a disconnect-style Slo-Blo fuse (3A @ 250 VAC) with a replacement fuse included. The panel wiring diagram is in the door, and all inputs and outputs are tested in the factory.
Reflash to another program
The C1050 keeps its full functionality, including the ability to reflash into a different controller program. Wiring diagrams are available free at proloncontrols.com.
SOURCE/SINK dipswitch per output
Each of the C1050's 4 triac outputs has its own SOURCE/SINK dipswitch on the controller.
Free Prolon Focus software
Remote monitoring and configuration with free Prolon Focus software, stand-alone or networked up to 127 nodes.
ZOT Supply is an authorized distributor of Prolon products.
Technical Specifications
| Panel | |
|---|---|
| Controller | Prolon C1050, Water Loop Controller program |
| Supply | 24 VAC ±10%, 50/60 Hz, Class 2 |
| Overcurrent Protection | Disconnect-style Slo-Blo fuse (3A @ 250 VAC), with additional replacement fuse included |
| Enclosure | NEMA 1 |
| Panel Dimensions | 12.25 in. W x 16.25 in. H x 6.25 in. D |
| Weight | 23 lbs (10.5 kg) |
| Isolation Relays | 17A @ 277 VAC on all digital outputs (C1050 = 4, M2000 = 5) |
| Environment | -4 to 122 °F (-20 to 50 °C), non-condensing |
| Panel Certification | Complete panel is UL508A certified |
| Certification | UL916 Energy Management Equipment, CAN/CSA-C22.2, RoHS, FCC part 15: 2012 class B |
| C1050 Controller Hardware | |
| Power | 2 VA (consumption), 32 VA (input) |
| Inputs | Supply water temp: thermistor 10K; Return water temp: thermistor 10K; Auxiliary temp: thermistor 10K; Auxiliary digital input: dry contact |
| Digital Outputs | 4 triac outputs, 10-30 VAC source or dry contact, 300 mA max (resettable fuse) |
| Analog Outputs | 1 output 0-10 VDC, 40 mA max (resettable fuse) |
| Indication Lights (LED) | State of each output / Communication / Power / State of microprocessor |
| Casing | Molded ABS, UL94-HB |
| Communication | Modbus RTU (RS485), up to 127 nodes |
| Baud Rates | 9600, 19200, 38400, 57600, 76800, 115200 |
| Connection | Removable screw-type terminal blocks (max 16 AWG) |
| Water Loop Controller Program | |
| Program | Water Loop Controller |
| Application | Controls a water loop system comprised of a boiler and a water tower with an internal pump |
| Program Inputs | Supply water, return water and auxiliary temp: 10K thermistor; auxiliary digital input: dry contact |
| Program Outputs | 4 triac outputs, each SOURCE (active) or SINK (passive, isolated dry contact) by on-board switch, 300 mA max (resettable fuse); output 1 heating (boiler); outputs 2 to 5 cooling actions (tower damper or bypass valve, spray pump, tower stage 1, tower stage 2); analog output 0-10 VDC, 40 mA max (resettable fuse) |
Documentation
Frequently Asked Questions
What is the Prolon PL-PN1-4Q?
A pre-wired one controller panel built with a Prolon C1050 controller running the Water Loop Controller program, in a UL508A certified NEMA 1 enclosure with isolation relays on all digital outputs.
What does the water loop program control?
It controls a water loop system comprised of a boiler and a water tower with an internal pump. Strategies include bypass valve control, cooling tower damper control and spray pump and cooling tower staging.
Which inputs does the PL-PN1-4Q use?
Supply water, return water and auxiliary temp: 10K thermistor; auxiliary digital input: dry contact.
What power does the panel require?
24 VAC ±10%, 50/60 Hz, Class 2. The C1050 draws 2 VA (consumption), 32 VA (input).
Are the outputs isolated and protected?
Yes. Every digital output is isolated by a relay rated 17A @ 277 VAC built into the panel, the triac outputs are rated 300 mA max with resettable fuses, and the panel has a disconnect-style Slo-Blo fuse (3A @ 250 VAC) with a replacement fuse included.
How does the PL-PN1-4Q communicate?
Modbus RTU (RS485), up to 127 nodes, at 9600 to 115200 baud. The panel contains 1 node and is configured with free Prolon Focus software.
What size is the PL-PN1-4Q panel?
12.25 in. W x 16.25 in. H x 6.25 in. D, and it weighs 23 lbs (10.5 kg).
Can the outputs switch an external power source?
Yes. Each triac output has a SOURCE/SINK switch. In SINK (passive) mode the output acts as an isolated dry contact, so an external source powers the load.
- Panel Type:
- Single Controler Panel
- Display:
- No Display
- Controller Type:
- Water Loop
- Communication:
- Modbus RTU (RS485)
