Spirax Sarco BC3150 is a blowdown controller for steam boilers. It controls TDS (total dissolved solids - salts in solution) by opening and closing a blowdown valve. The product works by controlling the conductivity of liquids, in conjunction with a Spirax Sarco conductivity sensor (CP10, CP30, or CP32) and a boiler blowdown valve or condensate dump valve.

Designed for harsh industrial environments, the controller is equipped with a 3-digit LCD graphic display and features continuous, purge, or pulsed output modes. It provides a 4-20mA retransmit output and supports infrared (IR) communications between adjacent controllers.

Outputs and Operating Modes

• Continuous Output: Used when the probe is mounted in the boiler. The probe constantly monitors the conductivity from the probe tip to the boiler shell.
• Purge Output: Used only when the probe is mounted in the blowdown line, ensuring the sensor measures the conductivity at boiler temperature.
• Pulsed Output: For smaller boilers where the capacity of the blowdown valve is relatively high compared to the boiler size. The blowdown may be set to pulse (e.g., 10 seconds on, 20 seconds off), slowing the rate at which boiler water is removed to prevent triggering a low water alarm.

Typical Applications

Boiler Control Systems (BCS)

The BC3150 is widely used in Boiler Control Systems for comprehensive TDS management.

Condensate Contamination Detection (CCD)

The Spirax Sarco CCD system monitors and displays the conductivity of condensate return, redirecting the flow to drain if conductivity increases above a pre-set level.

Front Panel Operations

The front panel provides direct access to parameter viewing and manual testing without entering the full password-protected commissioning menu.

Manual Test Buttons

• AL (Alarm): Tests the alarm relay and external circuits.
• Valve: Manually opens the blowdown valve to perform a purge.
• CLN (Clean): Electrically cleans the probe for 20 seconds to disperse scale and bubbles.

Installation Guidelines

Mechanical Installation

The BC3150 must be installed in a suitable industrial control panel or fireproof enclosure. It can be mounted on a 35 mm DIN rail, a chassis plate, or directly in a panel cutout.

Electrical Installation

Electrical Safety

Isolate the mains supply before touching any of the wiring terminals. The design relies on the building installation for overcurrent protection.

Signal and Probe Wiring Maximum cable length for all probes is 100 m (for 9990 and 999.0 ranges), 10 m (9.990 range), or 30 m (99.90 range).

Technical Specifications

Power and Environmental

Parameter	Specification
Mains voltage	110 V to 240 Vac at 50/60 Hz
Power consumption	7.5 W (maximum)
Ambient temperature	0 - 55 °C (32 - 131 °F)
Enclosure rating (front panel)	NEMA type 4 hose down only, IP65

Inputs and Outputs

Parameter	Specification
Probe types	CP10, CP30 and CP32
Conductivity ranges	0 - 9.99, 0 - 99.9, 0 - 999, 0 - 9990 ppm or μS/cm
TC Sensor type	Pt100 – Class B or better
4-20 mA Output	Minimum 0 mA, Maximum 20 mA (500 ohm max load)
Relay Contacts	2 × single pole changeover relays (SPCO), 3 amp @ 250 Vac

Operational Error Messages

Error message	Cause	Action
1 Power out	Loss of power during operation	Check wiring and power supply
2 Setup menu time out	No key pressed for 5 minutes	Re-enter commissioning mode
3 Alarm 1	High TDS alarm occurred	Check boiler operation and feedwater quality
4 Alarm is latched!	Safety lockout triggered	Enter password in setup mode to clear