The Spirax Sarco LP31 is a self-monitoring high level sensor designed specifically for steam boilers and conductive liquid vessels. The product uses a stainless steel body and 316L probe, with a maximum withstand pressure of 32 bar g and working temperature up to 239 °C. It has a unique self-monitoring function that can automatically detect probe and circuit faults, and is often used with the LC3050 or LC1350 controller for high level alarming and monitoring of boilers and external control water drums.
LP31 product photo
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Spirax Sarco LP31 Self-Monitoring Steam Boiler High Level Sensor
Self-monitoring high level sensor, for steam boilers and conductive liquid vessel alarming.
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Specifications
- Maximum boiler pressure
- 32 bar g
- Maximum working temperature
- 239 °C
- Maximum ambient temperature
- 70 °C
- Maximum sensor wire length
- 50 m
- Protection rating
- IP65
- Minimum conductivity (with LC1350)
- 1 mS/cm
- Minimum conductivity (with LC3050)
- 30 mS/cm
- Probe length options
- 500 mm, 1000 mm, 1500 mm
- Connection thread
- 1/2" BSP
- Electrical connection
- DIN43650
- Compatible controllers
- LC3050, LC1350
- Body material
- Austenitic stainless steel BS EN 10088-3 (1.4306)
- Probe material
- Austenitic stainless steel ASTM A276 316L
- Probe sleeve material
- PTFE
- Self-monitoring function
- Yes
Application scenarios
Steam boiler self-monitoring high level alarm
The LP31 can be directly installed on a steam boiler and is usually equipped with a protection tube, used with the LC3050 level controller. When the level rises and contacts the probe, a high level alarm is triggered; its self-monitoring function can detect probe and connection circuit faults and alarm.
External control water drum high level monitoring
Under conditions permitted by regulations, the LP31 can be installed in an external control water drum of the boiler, used with the LC3050 for high level detection and alarming. The probe can be cut to the required length before installation to adapt to the on-site set position.
High/low level detection of other conductive liquid vessels
The LP31 can be used with the LC1350 controller as a non-self-monitoring high level or low level sensor for fixed-point level detection of vessels other than steam boilers.
FAQ
What scenarios is the LP31 level sensor mainly used for?
The LP31, used with the LC3050 level controller, is for high-precision self-monitoring high level alarming of steam boilers and other vessels. The sensor is usually directly installed on the boiler and equipped with a protection tube; when permitted by regulations, it can also be installed in an external control water drum.
What is the level detection principle of the LP31?
Under normal conditions, the probe is located above the level, presenting high resistance to ground. When the level rises and contacts the probe, the resistance to ground decreases, and the controller triggers the alarm relay and issues an alarm signal and alarm sound. When the probe and its connecting wires fail, the self-monitoring function can also trigger an alarm.
What controllers can the LP31 be used with?
When used with the LC3050, the LP31 can be used for self-monitoring high level alarming; when used with the LC1350, it can be used as a simple non-self-monitoring high water level or low water level sensor. The specific configuration must be confirmed according to the actual model and application conditions.
What probe lengths and usage limits does the LP31 have?
The LP31 is available in three probe lengths: 500 mm, 1000 mm, and 1500 mm, which can be cut to the required length before installation. The maximum boiler pressure is 32 bar g, maximum temperature is 239 °C, maximum ambient temperature is 70 °C, and maximum sensor wire length is 50 meters.
What should be noted during installation of the LP31?
Before installation, the probe should be cut to the required length and connected to the corresponding controller. The sensor is installed via a 1/2-inch BSP threaded connection, and PTFE sealing tape can be used for sealing; weather protection measures should be taken for outdoor installation. The boiler water level and alarm control system should undergo routine testing and inspection.