AUTOFLAME Mk8 MM Installation And Commissioning Guide

3 Water Level Control
04.09.2016 Mk8 MM Expansion Features Installation and Set-Up Guide Page 25
3 WATER LEVEL CONTROL
3.1 Overview
3.1.1 Safety
The purpose of a steam boiler is to provide generate steam in a safe and efficient manner. The heat
produced from the fuel combustion will be transferred to the water in the boiler. The water will then
evaporate to steam under pressure. The boiler manufacturer will have designed the boiler so that the
steam is drawn out from the header at a safe rate.
As the steam is released, water must be fed into the boiler to ensure that the level does not reach a
critical low. If the burner continues to fire without water in the boiler, these dangerous conditions could
result in an explosion due to the metal overheating. Hence, the water level in a steam boiler must be
continuously monitored and controlled so that when firing there is always water in the boiler. All local
codes and regulations must be met. If the burner fires with no water in the steam boiler, serious
damage will occur and there is a high risk of an explosion.
**WARNING**
ANY PERSON WORKING ON A BOILER MUST BE ADEQUATELY TRAINED AND
HAVE A THOROUGH APPRECIATION OF THE BOILER PLANT. IT IS THE
RESPONSIBILITY OF THE FACTORY TRAINED TECHNICIAN TO ENSURE THAT THE
SYSTEM OPERATION MEETS LOCAL CODES AND REGULATIONS.
3.1.2 Autoflame Water Level Control
The Autoflame water level control in the Mk8 MM focuses on safety and accuracy in controlling the
water level in a steam boiler. The intelligent water level control includes high water alarms, 1
st
low and
2
nd
low alarms. Alarm level reporting deals with the ability to determine whether the current water level
in the boiler is above or below a predetermined level. These levels vary with each installation, and
must therefore be programmed on site by a qualified commissioning engineer.
The feed water flow is managed by 3-element control, in response to the water level measured by the
level sensing devices’ readings, boiler pressure and the burner’s firing rate. The flow is controlled by a
fully modulating feed water/VSD or by using an on/off signal from a feed water pump. The feed water
going into the boiler can be controlled in the following ways by setting expansion option 2:
 Pump on/off only
 Pump on/off and servomotor control
 Pump on/off and VSD control
The Autoflame 3-element level control has been granted a worldwide patent; being the only system
that can combine firing rate, steam pressure and water level within one controller for the purpose of
improving feed water control. Safety, accuracy and integrity are guaranteed.
The levels which are commissioned when using capacitance probes and/or external level sensing 4-
20mA device include high, control point, 1
st
low, 2
nd
low and end of probe.
The level of the water in the boiler should be maintained appropriate to the amount of steam being
generated. Should the water level drop below this ideal level by an excessive amount, it is necessary
to stop the burner firing. If there is insufficient water in the boiler damage may occur to its structure,
and in extreme cases, an explosion. The water level control herein is designed to maintain a
satisfactory level of water in the boiler, whilst controlling and reporting low water level conditions.

AUTOFLAME Mk8 MM Specifications

General

Brand	AUTOFLAME
Model	Mk8 MM
Category	Controller
Language	English