11
2
outflow
to the heating
system
1
7.4.2.
GUIDELINES CONCERNING INSTALLATION AND
PROTECTION OF HEATING BOILERS IN THE OPEN SYSTEM.
Exemplary protection diagrams for a water heating system equipped
with one boiler or heat exchanger are presented in the pictures below.
Hint!
The executed central heating system should meet the
requirements specified by the Polish standards (PN-91/B-
02413 and BN-71/886427) on the protection of open system
water heating devices and expansion vessels.
In case of installation of the boiler in a country other than
Poland, it is obligatory to apply relevant requirements and
standards of this country.
Protection of water heating installation of the open system should
consist of primary and supplementary protecting devices as well as
fittings.
The basic protecting devices should be used in all installations of the
open system.
The following elements are the basic protecting devices:
•expansion vessel,
•protecting pipes
- safety pipe
RB
and expansion pipe
RW
,
•sweep pipe
RP,
•deaeration pipe
RO.
Supplementary protecting devices should be used depending on the
type of heat source, its power and the location of primary protecting
devices.
Hint!
The most important requirements regarding the protective
devices
1)
an open system expansion vessel of the capacity of at least 4-
7% of the whole heating system capacity;
2)
safety pipe -
RB
of diameter depending on boiler's thermal
power;
3)
the vessel must be connected by means of expansion-
RW
,
signalling-
RS
,
sweep-
RP
and deaeration-
RO
pipes;
4)
the expansion, signaling, sweep, deaeration and circulation
pipes allowing for maintaining appropriate temperature in the
vessel.
5)
expansion vessel should be located over a heat source, with
vertically lead safety pipes, on such a height that any break in water
flow will occur at any point of the water circuits, and it will be
possible to vent the system. The maximum height of installation of
the expansion vessel should not exceed 30 m.
Values of internal diameters of pipes protecting the boilers assumed
according to PN-91/B-02413 are presented in the below table.
Table 6. Nominal and internal dimensions of safety and expansion pipes.
Picture 5. Protection diagram for a central heating system equipped with one boiler
or heat exchanger, upper distribution, and pump installed on the return pipe.
The protection diagram presented in picture 5 can be also used for
the following water heating systems:
-
upper distribution, pump on supply pipe,
-
upper distribution, pump on return pipe,
-
bottom distribution, pump on supply pipe,
-
upper and bottom distribution with gravitational circulation.
Hint!
It is strictly forbidden to use valves and gates on the safety pipe;
on its whole length, the pipe is to be free from neckings and
bends. In case of lack of possibility of installation of the safety
pipes in the shortest and simplest way, its installation location
and diameter should also meet the PN-91/B-02413 standard.
Hint!
In case when more than one heating boiler is installed in a boiler
room,
each of them is to be equipped with protection in accordance
with PN-91/B-02413, taking into account compulsory regulations
regarding the heat filter insulation of the protection system.
Hint!
The expansion vessel, safety pipes as well as expansion,
signaling and sweep pipes must be located in an area with a
temperature above 0°C.
Hint!
In case of absence of the thermal insulation or location of the
vessel not in accordance with PN-91/B-02413, complaints about
leakage in the period of temperature falling below 0°C may
constitute a basis for complaint rejection and refusal to carry our
repair or replace the central heating boiler.
Picture 6. Exemplary protections diagram for boiler in an open system: 1-boiler; 2-
open expansion vessel.
Thermal power of boiler
or heat exchanger [kW]
Safety pipe [mm]
Expansion
pipe [mm]
Over
Up to
Nominal
diameter
Internal
diameter
Nominal
diameter
Internal
diameter
_
40
25
27.2
25
27.2
For expansion pipe - thermal power of source
RO
RB
System deaeration acc. to
standard PN-91/B-02420
RW
RP
RS
RB
RW
PN-91/B-02413-4
return from
system
