ICI Caldaie REX Technical Manual - page 24
23
5 START
UP
WARNING: Before start up insert wholly turbolators into the smoke tubes ensuring that they have
been pushed inside for at least 100 mm.
5.1 PRELIMINARY
CHECKS
Before starting the boiler, check that:
- The
rating plate specifications and power supply network (electricity, water, gas or fuel oil) specifica-
tions correspond;
- The
burner
power range is compatible with the power of the boiler;
-
The boiler room also contains the instructions for the burner;
- The
flue gas exhaust pipe is operating correctly;
- The
air inlet supply is well dimensioned and free from any obstacle;
- The
manhole, the smokebox and the burner plate are closed in order to provide a complete flue gas
seal;
-
The system is full of water and that any air pockets have therefore been eliminated;
- The
anti-freeze protections are operative;
- The
water
circulation pumps are operating correctly.
-
The expansion vessel and the safety valve(s) have been connected correctly (with no interception) and
are properly operating.
-
Check the electrical parts and thermostat operation.
5.2 WATER
TREATMENT
The most common phenomena that occur in heating systems are:
- Scaling
Scale obstructs heat transfer between the combustion gases and the water, causing an abnormal in-
crease in the temperature of the metal and therefore reducing the life of the boiler.
Scale is found mostly at the points where the wall temperature is highest and the best remedy, at con-
struction level, is to eliminate areas that overheat.
Scale creates an insulating layer which reduces the thermal transfer of the generator, affecting system ef-
ficiency. This means that the heat produced by burning the fuel is not fully exploited and is lost to the flue.
Scale diagram
Key
%
% fuel not used
mm mm scale
- Corrosion on the water side
Corrosion of the metal surfaces of the boiler on the water side is due to the passage of dissolved iron
through its ions (Fe+). In this process the presence of dissolved gases and in particular of oxygen and
carbon dioxide is very important. Corrosion often occurs with softened or demineralised water which has
a more aggressive effect on iron (acid water with Ph <7): in these cases, although the system is protected
from scaling, it is not protected against corrosion and the water must be treated with corrosion inhibitors.
5.3 FILLING THE SYSTEM
The water must enter the system as slowly as possible and in a quantity proportional to the air bleeding
capacity of the components involved. Filling times vary depending on the capacity and characteristics of
the system but should never be less than 2 or 3 hours.
In the case of a system with closed expansion vessel, water must be let in until the pressure gauge indicator
reaches the static pressure value pre-set by the vessel.
Heat the water to maximum temperature and never over 90°C. During this operation the air contained in the
water is released through the automatic air separators or through manual bleed valves. The water dis-
charged from the system with elimination of the air is made up by the automatic or manual filling valve.