Table of Contents
Advertisement
INSTALLER
WATER IN CENTRAL HEATING SYSTEMS:
INSTRUCTIONS FOR THE DESIGN, INSTALLATION AND MANAGEMENT OF CENTRAL HEATING SYSTEMS
1 . Chemical and physical characteristics of water
The chemical and physical characteristics of water used in central heating systems must conform to the requirements
of EN 14868 standard and to the following tables:
with furnace power < 150 kW
pH
Hardness
Electrical
μs/cm
conductivity
Chlorides
mg/l
Sulphides
mg/l
Nitrides
mg/l
Iron
mg/l
(*)
values for water in system after 8 weeks of functioning
General note on water used to top up systems:
− If softened water is used to top up a system, 8 weeks of functioning after topping up, verify that the water in
the system respects the above limits, in particular for electrical conductivity.
− This check is not necessary if demineralised water is used to top up the system.
2 . Central heating systems
9
Do not use automatic filling devices to add water to
central heating systems. Use a manual device inste-
ad and record top-ups in the system service book.
9
If a system comprises a number of boilers, when
that system is first put into service, make sure that
all the boilers function simultaneously or on a short
interval rotation basis in order to evenly distribute
initial limescale deposits.
9
When you finish installing a system, always flush it
out to remove installation residues.
9
Water used to fill a system for the first time and wa-
ter used to top it up must always be filtered (using
synthetic or metal mesh filters with a filtration ra-
ting of no less than 50 microns) to prevent sludge
from forming and triggering deposit corrosion.
9
Before re-filling an existing system, clean and flush
it out thoroughly. Only fill the boiler after the central
heating circuit has been thoroughly flushed out.
ALUMINIUM BOILERS
Water with
Water used for
system ope-
first filling
rating (*)
6-8
°fH
< 10°
7-8
pH
< 10°
Hardness
Electrical
< 200
conductivity
< 25
Chlorides
< 25
Sulphides
< 25
Nitrides
< 0,5
Iron
2 . 1 New central heating systems
Initial filling of the system must be performed slowly. In
theory, once filled and bled of all air, a heating circuit
should not need topping up.
Systems should also be operated at maximum working
temperature the first time they are started up, in order
to facilitate de-aeration. (Gas is not released from the
water at low temperatures.)
2 .2 Reconditioning old central heating systems
If a boiler has to be replaced, do not refill the entire
central heating circuit if the quality of water in it con-
forms to requirements. If the quality of water fails to
conform to requirements, either recondition the old
water or separate the water circuits (water in the boiler
circuit must conform to requirements).
24
ALUMINIUM BOILERS
with furnace power > 150 kW
Water used for
first filling
6-8
°fH
< 5°
μs/cm
mg/l
mg/l
mg/l
mg/l
Water with
system ope-
rating (*)
7-8
< 5°
< 150
< 15
< 15
< 15
< 0,5
Advertisement
Table of Contents
