2.1 BOILER
ROOM
The boiler room should feature all the
characteristics required by standards
governing liquid fuel heating systems.
2.2
BOILER ROOM DIMENSIONS
Position the boiler body on the founda-
tion bed, which should be at least 10
cm high.
The body should rest on a surface
allowing shifting, possibly by means of
sheet metal.
Leave a clearance between the boiler
and the wall of at least 0.60 m, and
between the top of the casing and the
ceiling of 1 m (0.50 m in the case of
boilers with incorporated D.H.W. tank).
The ceiling height of the boiler room
should be less than 2.5 m.
2.3
CONNECTING UP SYSTEM
When connecting up the water supply
to the boiler, make sure that the speci-
fications given in fig. 1 are observed.
All connecting unions should be easy to
disconnect by means of tightening
rings. A closed expansion tank system
must be used.
2.3.1 Accessories
(fig. 2)
To ensure boiler efficiency, and a pres-
sure relief valve set to 3 bar (14) and a
hydrometer to check the system pres-
sure (16).
Install a pressure relief valve calibrated
to 6 bar (7) on the boiler water outlet
pipe to prevent the risk of bursting due
to excess pressure build up.
If the boiler safety valve cuts in fre-
quently, install a 5-litre expansion ves-
sel (15) with maximum operating pres-
sure of 8 bar on the hot water circuit.
The tank should be fitted with a natural
rubber food-grade diaphragm.
The central heating circuit pump (4)
can be installed at the rear of the boil-
er in place of the connection union 1”
pos. 3 fig. 4/a (we suggest you mount
the pump without the WILO-YONOS
PARA RS 15/6 RKC-KU air degasser).
2.3.2 Filling the water system
Before connecting the boiler, thor-
oughly flush the system to eliminate
scale which could damage the appli-
ance.
Filling must be done slowly so as to
allow any air bubbles to be bled off
through the air valves.
In closed-circuit heating systems, the
cold water filling pressure and the pre-
charging pressure of the expansion
vessel should be no less than or equal
to the height of the water head of the
installation (e.g. for water head of 5
meters, the vessel pre-charging pres-
sure and installation filling pressure
should be at least 0.5 bar).
2.3.3 D.H.W. production
During the preparation of hot water,
the circulating pump installed on the
boiler circuit remains in operation until
the boiler thermostat probe detects
the pre-selected value.
Once the boiler thermostat has reach
the set point, and the selector has
been set to winter operation with the
room thermostat on demand, the cen-
tral heating circuit pump (not supplied)
can be actuated.
All residual air in the boiler coils must
be bled at the first start-up to ensure
proper operation.
To facilitate this operation, position
the slot of the release screw on the
check valve horizontally (6 fig. 2).
Once the air has been bled, return
the screw to its original position.
Hot water for sanitary use is prepared
by the boiler in AISI 316L stainless
steel, which is fitted with a special spi-
ral-shaped stainless steel heat exchan-
ger, a magnesium anode to protect
the boiler and an inspection flange to
simplify checking and cleaning.
2.3.4 Characteristics
of feedwater
To prevent lime scale and damage to
the tap water exchanger, the water
supplied should have a hardness of no
more than 20°F.
In all cases the water used should be
tested and adequate treatment devi-
ces should be installed. To prevent
lime scale or deposits on the primary
exchanger, the water used to supply
the heating circuit should must be
treated in accordance with UNI-CTI
8065 standards.
The water used for the central heating
system should be treated in the fol-
lowing cases:
– For extensive systems (with high
contents of water).
– Frequent addition of water into the
system.
– Should it be necessary to empty the
system either partially or totally.
2.4
SMOKE EXHAUST
2.4.1 Connecting up flue
The flue is of fundamental importance
for the proper operation of the boiler; if
not installed in compliance with the
standards, starting the boiler will be
difficult and there will be a consequent
formation of soot, condensate and
encrustation.
The flue used to expel combustion
products into the atmosphere must
meet the following requirements:
– be constructed with waterproof
materials, and resistant to smoke
temperature and condensate;
– be of adequate mechanical resilience
and of low heat conductivity;
– be perfectly sealed to prevent cool-
ing of the flue itself;
– be as vertical as possible; the termi-
nal section of the flue must be fitted
with a static exhaust device that
ensures constant and efficient
extraction of products generated by
combustion;
– to prevent the wind from creating
pressure zones around the chim-
ney top greater than the uplift
force of combustion gases, the
exhaust outlet should be at least
0.4 m higher than structures adja-
cent to the stack (including the
roof top) within 8 m;
– have a diameter that is not inferior
to that of the boiler union: square or
rectangular-section flues should
have an internal section 10%
greater than that of the boiler union;
– the useful section of the flue must
conform to the following formula:
S
resulting section in cm
2
K
reduction coefficient for liquid
fuels:
– 0.045 for firewood
– 0.030 for coal
– 0.024 for light oil
– 0.016 for gas
P
boiler input in kcal/h
H height of flue in meters, mea-
sured from the flame axis to the
top of the flue reduced by:
– 0.50 m for each change of
45
2
INSTALLATION
P
S
= K
√
H
