Spirax Sarco LC2650 is a level controller designed for conductive liquids, offering precise control for boilers, tanks, and pressurized vessels. It is suitable for operating limits up to 32 bar at 239°C and requires a minimum fluid conductivity of 5 μS/cm. The unit features a high-contrast LCD graphics display and a five-button keypad for easy navigation and configuration.

System Overview and Functions

The controller compares input signals with a user-defined Set Point to maintain liquid levels through various control strategies:

• On/Off Control: Ideal for pump or solenoid valve operation, featuring two alarm outputs and isolated retransmission.
• Modulating Control: Supports Valve Motor Drive (VMD) or 4-20 mA control signals.
• Two or Three Element Control: Incorporates feedback from steam meters and feed-forward from water meters to compensate for boiler swell and variations in feedwater flow.

Monitoring and Display

The display is divided into process variable digits, an information line for status/alarms, and three bar graphs showing percentage values of the gauge glass. A built-in trend screen records level variations over set time intervals (minutes, hours, or days).

Interface and Communication

• RS485/Modbus: Enables remote access to parameters via a two or four-wire multi-drop network.
• Infrared (IR): Allows communication between adjacent Spirax Sarco controllers on a DIN rail or panel without physical wiring.
• Diagnostic Tools: A dedicated test menu allows measuring inputs and manually forcing outputs for simplified commissioning and fault finding.

Installation and Mounting

The product is designed for vertical orientation and can be installed via three methods:

1. DIN Rail: Securely clips to 35 mm DIN rails.
2. Chassis Plate: Screw-mounted directly to the enclosure backplate.
3. Panel Cutout: Flush-mounted in a panel with a bezel for IP65 front protection.

Commissioning Security

Access to commissioning mode is protected by a factory-set pass code (7452) to prevent unauthorized tampering or hazardous programming errors.

Technical Data Summary

Parameter	Specification
Mains Voltage	110 V to 240 Vac (50/60 Hz)
Power Consumption	7.5 W Maximum
Fluid Compatibility	Conductive liquids (Min 5 μS/cm)
Operating Limits	Up to 32 bar @ 239°C
Relay Rating	3A @ 250 Vac (Resistive load)
Retransmission	Isolated 4-20 mA (1% FSD resolution)
Enclosure Material	Polycarbonate with Silicone rubber front panel