12
2.5.6 - CONNECTION OF THE
EXPANSION PIPE AND VESSEL
An expansion vessel is always necessary, to
compensate the water volume increase due
to the heating.
The TS 3P boilers are suitable for fully pumped
systems, which can be open vented or sealed.
In the 1
st
case the height of the hydrostatic
column must be, at least, 3 m above the boiler
casing and the capacity of the expansion
cistern shall be able to contain, between the
water surface and the overflow pipe, the
volume increase of all the water of the C.H.
system. Preference shall be given to high and
narrow cisterns, to expose to the air a surface
as small as possible, thus reducing the water
evaporation.
In the 2
nd
case the vessel capacity has to be
calculated taking into consideration:
-
The total volume of the water contained
in the system.
The maximum working pressure of the
system (see setting of PRV).
-
The maximum working pressure of the
expansion vessel.
-
The initial preloading of the expansion
vessel.
-
The maximum working temperature of the
boiler (the maximum setting of the
thermostat fitted onto the panel board is
90 °C; under this aspect it it suggested to
consider 100 °C.
The expansion pipe connects the C.H.
system to the expansion vessel.
This pipe which starts from the connecting
point T3 (see table DIMENSIONS), must have
NO gate valve on it.
2.5.7 - SHUNT PUMP
The TRISECAL 3P boilers must be operated
under forced water circulation and at a minimum
water temperature of 30 °C, if operated with
oil, or 35 °C, if operated with natural gas,
when the boiler is used in sliding temperature
and at part load (see par. 7.2).
In the C.H. systems equipped with mixing
valve it is convenient to foresee a shunt pump
Pr to guarantee the necessary water circulation
through in any possible opening condition of
the mixing valve and to guarantee therefore
the respect of the minimum return temperature
indicated.
This pump will be sized according to the
following formula:
Q = P x 22
where Q = Water flow rate in liter/h
P = Boiler nominal output in kW
and the manometric head 1-2 m w.c.
2.6 - FURNACE DOOR:
ADJUSTMENT,
OPENING & CLOSING
A special attention has been paied to the
design of the front door, because in all the
pressurised boilers a good quality of the doors
is a necessary condition for the best operation
of the boiler.
With the furnace working in positive pressure,
in fact, every minimum fissure could cause a
leakage of high temperature combustion
products, with consequent burning of the
gasket and overheating of the door up to its
permanent deformation.
For these reasons the door structure of the
TS 3P boilers, in addition to the fact to be
very strong, has also the possibility to be
adjusted: it can be lifted, lowered and also
slanted, getting, thus, always the perfect
centering of the sealing gasket.
The special inner lining in ceramic fiber
reduces, furthermore, the time to reach the
boiler steady state condition and then reduces
drastically the formation of condensate at the
boiler start.
An interesting particularity related to the front
door, is the soundness self keeping system,
made with elastic steel plates which compen-
sate and reposition the door exactly onto the
sealing rope, also in case the ceramic fiber
sealing rope becomes hard.
2.6.1- IMPORTANT NOTE
Before opening the furnace door it is necessary
to adopt the following precautions:
-
Close the fuel cock (oil or gas) to the burner.
-
Cool down the boiler by keeping the water
circulating through it, and only then switch
off the power.
-
Put on the boiler a Warning notice with
the following text: DO NOT USE, BOILER
UNDER SERVICE, OUT OF ORDER.
