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 2016

AI-P402-13

AB Issue 8

LCS4000

Level Control Systems

Installation and testing

of self-monitoring low level alarms and boiler feedwater control/high alarm

Typical installation

This document does not contain sufficient information to install

the system safely. See the Installation and Maintenance

Instructions supplied with the products for full details.

The Spirax Sarco LCS4000 boiler water level control and alarm

system is suitable for automatically controlled steam boilers and

provides the control and alarm functions specified by British

Standards in BS 12953 and by the SAFed and CEA, in consultation

with the Health & Safety Executive, in BG01.

The low level alarms are of the high integrity type and whilst a trained

boiler attendant should check the plant daily, he need not be on site

at all times. There should, however, always be someone available

on site such as a watchman or porter who is suitably trained to

respond to alarms and take appropriate action.

The level controls and level alarms are probably the most important

controls on the boiler for ensuring safety and should only be installed

and maintained by suitable trained personnel. Spirax Sarco can

install, commission and provide a regular maintenance service.

Note: Consult Spirax Sarco if conductivity

is less than 100 μS/cm and is likely to

vary by more than 2:1.

High integrity self-monitoring level alarms do not require daily testing

but the weekly test should be carried out or witnessed by a

responsible person who appreciates the hazards involved and has

been suitably trained in the safe operation of the boiler and its

controls. At no time during the test should the water be lowered to

the extent that it disappears from the gauge glass.

1. With the feedwater isolated, allow the water level to fall by

evaporation until the burner shuts down at 1st low alarm.

2. Blow down the boiler until the 2nd low alarm sounds and the

burner controls go to lockout.

3. Raise the water level to normal, reset the lockout and allow the

burner to refire. Press the test button (or the externally wired

button if fitted) on the LC3000 for 2nd low to ensure that the

burner shuts down at the 2nd low level alarm.

4. Under hand control raise the water level to the high alarm level.

Check that the high alarm sounds.

5. Return all valves and controls to normal and monitor the boiler

until satisfied that it is operating normally.

The Health and Safety Executive recommend from experience that

the boiler controls should be serviced at least at quarterly intervals.

Where the regular tests are carried out properly in a well run boiler

house with good water treatment, it may be that only an annual

inspection of the probes etc. is required. This is a matter, however,

for the user to decide in liaison with his insurance company inspector

in order to determine a sensible inspection programme to suit the

individual boiler plant.

LC3050

controller

LC3050

controller

LC3050

ALARM

OK

AL

LP30

probe

LC3050

ALARM

OK

AL

LP20 probe /

PA20 preamplifier

Minimum conductivity:

LC3050 30 μS/cm or 30 ppm

LC2650 and LC2250 5 μS/cm or 5 ppm

LP30

probe

Weekly test

Boiler

High alarm

1st low

2nd low

Protection tubes

Quarterly inspection

Modulating

control

band

LC2250

controller

LC2250

OK

LC2650

controller

LC2650

%

0

SP

PV

AL

OK

or

100

50

AL

We recommend a regular inspection as follows:

1. Inspect the probe plugs for moisture.

2. Unscrew the probes and wipe away any dirt from the probe

tips. If any hard scale is present it may be an indication of

more serious scale formation elsewhere in the boiler.

Investigate water treatment.

3. Remove the actuator cover from the feedwater control valve

and inspect the actuator linkages etc. for tightness and correct

operation, and inspect wiring. Test the feedwater control valve

for correct operation over its full stroke, for gland leakage and

for tight shut-off.

4. Inspect the wiring and controllers for damage.

5. Reassemble and carry out a full functional check.

Feedwater control valve

2.3.12