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 2013

TI-P402-138

AB Issue 2

PA420

Preamplifier

Description

The PA420 preamplifier, used with a Spirax Sarco capacitance

probe, is a loop powered two wire 4 - 20 mA level transmitter.

It amplifies the capacitance measured and converts it to a

4 - 20 mA output proportional to the liquid level. It is compatible

with all Spirax Sarco current input controllers / transmitters.

The preamplifier consists of a tubular austenitic stainless steel

body which screws onto the top of the probe, and has a

Type A EN 175301-803 (DIN 43650) / ISO 4400 connector with

Pg 11 cable gland.

The PA420 has two buttons and a dual coloured light (red and

green) for use during commissioning.

Principal features:

-

Compact, rigidly mounted.

-

Can be removed / replaced without disturbing the probe.

-

No maintenance needed.

-

Suitable for all probe lengths (370 - 1 500 mm).

Approvals:

-

TÜV, VdTÜV-Merkblatt, Wasserstand 100 - 2010.

-

Electromagnetic Compatibility Directive 2004 / 08 / EG.

Caution:

The probe is not suitable for outside installation without

additional environmental protection.

Dimensions (approximate) in mm

39 mm

105 mm

Pg 11 cable gland

Withdrawal distance

for cable socket 15 mm

1

4

Austenitic stainless steel 300 series

Polyamide (Glass filled)

Silicone rubber

Nitrile rubber

2

3

1⁄2" BSP

5 mm

Material

Weight

Ø28

Limiting conditions

Ambient temperature range

Pollution degree

Water conductivity

Maximum cable length

Technical data

Voltage drop (across the device)

Loop current

Maximum load

Linearity

Isolation

0 - 70°C

3

5 μS / cm or 5 ppm

100 m (screened)

9 - 26.4 Vdc

4 - 20 mA

500 W

2% FSD

100 Vdc (capacitive)

Materials

No Part

1 Body

2 Cable connector

3 Connector gasket

4 'O' ring

mm

approximately 0.25 kg

including packaging.

Safety information, installation and maintenance

This document does not contain sufficient information to install

the product safely. See the Installation and Maintenance

Instructions provided with each unit.

Installation note:

The PA420 is screwed into the top of the capacitance probe and

hand tightened. An 'O' ring is supplied to provide a seal. An

'O' ring is also supplied with the probe. Use only one 'O' ring.

Caution: Do not install the probe outdoors without additional

weather protection.

Maintenance note:

No special maintenance is required.

Boiler water level controls do, however, require periodic testing

and inspection, which is described in separate literature.

Spare parts

There are no available spare parts for this unit.

How to specify

Preamplifiers shall be Spirax Sarco type PA420 for use with

Spirax Sarco capacitance probes. Preamplifiers shall have

austenitic stainless steel bodies and a screwed connection, with

a DIN 43650 connector and Pg 11 cable gland.

How to order

Example: 1 off Spirax Sarco PA420 preamplifier.

2.3.20