Controller
C1050
Program
Boiler
Supply
24 VAC, Class 2
Outputs
4 DO / 1 AO
Protocol
Modbus RTU (RS485)
Panel
NEMA 1, UL508A
Overview
The Prolon PL-PN1-4C is a pre-wired, UL508A certified NEMA 1 control panel built with one Prolon C1050 controller running the Boiler Controller program, which operates staged boilers, as well as the associated pumps and valves. Isolation relays on all digital outputs, overcurrent fuse protection and clearly marked terminal blocks come factory wired.
Program strategies include outside temperature reset, lead-lag sequences and pump exercise intervals. 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-BLR Controller datasheet REV 7.3.0 / PL-DATA-C1050BLR-C/F-EN; Prolon C1050 Boiler Controller Hardware Guide REV 7.3.2; Prolon One Controller Panel product page (proloncontrols.com) retrieved 2026-09-22. Reviewed September 2026.
Best For
- Staged boiler plants with lead-lag boilers and pumps
- Hot water loops that need outside temperature reset
- Boiler rooms that want a UL-listed, pre-wired control enclosure
Warranty
For warranty coverage on this Prolon panel, contact ZOT Supply at sales@zotsupply.com or 855-825-2811.
Key Features
Staged boiler sequencing
Operates staged boilers with their pumps and valves, with lead-lag sequences, outside temperature reset and pump exercise intervals.
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, Boiler 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 | Outside air: thermistor 10K; Return Water: 10 K thermistor; Supply Water: 10 K thermistor; Proof of pump: dry contact |
| Digital Outputs | 4 triac outputs, 10-30 VAC source or sink, 300 mA max (resettable fuse) |
| Analog Outputs | 1 output 0-10 VDC / 2-10 VDC / 0-5 VDC, 40 mA max (resettable fuse) for the valve |
| Indication Lights (LED) | State of each output / Communication / Supply / 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 (16 AWG max) |
| Boiler Controller Program | |
| Program | Boiler Controller |
| Application | Operates staged boilers, as well as the associated pumps and valves |
| Program Inputs | Outside air, return water and supply water: 10K thermistor; proof of pump: dry contact |
| Program Outputs | 4 triac outputs; analog output: 1 output 0-10 VDC / 2-10 VDC / 0-5 VDC for the valve |
Documentation
Frequently Asked Questions
What is the Prolon PL-PN1-4C?
A pre-wired one controller panel built with a Prolon C1050 controller running the Boiler Controller program, in a UL508A certified NEMA 1 enclosure with isolation relays on all digital outputs.
What does the boiler program control?
It operates staged boilers, as well as the associated pumps and valves. Strategies include outside temperature reset, lead-lag sequences and pump exercise intervals.
Which inputs does the PL-PN1-4C use?
Outside air, return water and supply water: 10K thermistor; proof of pump: 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-PN1-4C 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-PN1-4C panel?
12.25 in. W x 16.25 in. H x 6.25 in. D, and it weighs 23 lbs (10.5 kg).
Does the C1050 boiler program keep its own schedule?
The C1050 hardware platform does not have an onboard real time clock. It defaults to occupied mode unless an occupancy state is received from the Prolon network.
- Panel Type:
- Single Controler Panel
- Display:
- No Display
- Controller Type:
- Boiler
- Communication:
- Modbus RTU (RS485)
