Boiler house

Level controls

Local regulations may restrict the use of this product to below the conditions quoted.

In the interests of development and improvement of the product, we reserve the right to change the specification without notice. © Copyright 2014

2.3.23

TI-P402-81

AB Issue 6

LP31

High Integrity, Self-monitoring

High Water Level Alarm Probe

Description

The Spirax Sarco LP31 is used in conjunction with an LC3050

controller to provide a high integrity, self-monitoring alarm for

detection of high water levels in steam boilers and other vessels.

The probe is normally installed direct in the boiler shell in a

protection tube, but can be mounted in an external chamber if

regulations permit.

The LP31 is supplied in three nominal tip lengths, and is cut to the

exact length required prior to installation.

In normal operation, the tip is above the water level, and has a high

resistance path to earth. If the water level rises to touch the probe

tip, the resistance to earth drops, causing the alarm relays in the

controller to be de-energised and the alarm to sound.

The LP31 is designed so that its tip and wiring connection integrity

is monitored by the controller, causing an alarm signal in the event

of a fault occurring.

The LP31 can also be used as a simple (non self-monitoring) high

or low level probe with an LC1350 level controller.

A DIN 43650 cable socket with Pg 11 cable gland is supplied with

the unit.

Approvals:

The LP31 is also available with a 1⁄2" NPT screwed connection,

approved to UL61010. Please note that this version will not

be marked and is not suitable for Europe.

Caution:

The probe is not suitable for outside installation without

additional environmental protection.

Available tip lengths mm (inches)

500 (19.7"), 1 000 (39.4") and 1 500 (59").

Limiting conditions

Nominal pressure rating

Maximum boiler pressure

Maximum temperature

Maximum ambient temperature

Technical data

Maximum probe cable length

LC1350

LC3050

Material

1

2

3

4

5

6

7

8

Cable socket

Pg 11

Cable gland

Probe body

PN40

32 bar g

239°C

(462°F)

70°C

(158°F)

50 metres (164 ft)

1μS/cmor1ppm

30 μS/cm or 30 ppm

(464 psi g)

Minimum conductivity

Materials

No. Description

1 Cable socket

2 Flat gasket

3 Probe connector

4 Cover assembly

5 Name-plate

6 Body

7 Probe tip sleeving

8 Probe tip

Polyamide, glass filled

Silicone rubber

Polyamide, glass filled

Austenitic stainless steel

Polycarbonate

Austenitic

Probe tip

stainless steel

PTFE

Austenitic

stainless steel

BS EN 10088-3 (1.4306)

ASTM A276 316L