10
Rittal air/water heat exchanger assembly instructions
4 Assembly and connection
EN
c) Fixed pipework with G
3
/
8
˝ internal thread
(Model No. 3201.900)
The G
3
/
8
˝ internal thread adaptor, available as an
accessory, allows you to connect fixed pipework to
the air/water heat exchanger for both the inlet and
the return.
To this end, you will need to remove the connector
sleeve attached to the device (see fig. 16, page 9).
d) Fixed pipework with
1
/
2
˝ NPT
(Model No. 3201.930)
The
1
/
2
˝ NPT adaptor, available as an accessory,
allows you to connect fixed pipework to the air/water
heat exchanger for both the inlet and the return.
To this end, you will need to remove the connector
sleeve attached to the device (see fig. 16, page 9).
4.5.1 Notes on water quality
To ensure the reliable operation of the above-
mentioned units, the VBG guidelines for cooling
water must be observed (VGB-R 455 P).
The cooling water must not contain any limescale
deposits; in other words, it should have a low level of
hardness, in particular, a low level of carbonate
hardness. For recooling within the plant, the carbon-
ate hardness should not be too high. On the other
hand, the water should not be so soft that it attacks
the materials. When recooling the cooling water, the
salt content should not be allowed to increase exces-
sively due to the evaporation of large quantities of
water, since electrical conductivity increases as the
concentration of dissolved substances rises, and the
water thereby becomes more corrosive.
Always add the appropriate volume of fresh water.
Always remove part of the enriched water.
The following criteria for the cooling water must be
observed:
– Water with high gypsum content is unsuitable for
cooling purposes because it has a tendency to
form boiler scale that is particularly difficult to
remove.
– The cooling water should be free from iron and
manganese, because otherwise deposits may
occur that accumulate in the pipes and block
them.
– At best, organic substances should only be
present in small quantities, because otherwise
sludge deposits and microbiological contamina-
tion may occur.
4.5.2 Preparation and maintenance of the water
in recooling systems
Depending on the type of installation to be cooled,
certain requirements are placed on the cooling water
with respect to purity. According to the level of con-
tamination and the size and design of the recooling
systems, a suitable process is used to prepare and/
or maintain the water.
The most common types of contamination and most
frequently used techniques to eliminate them in
industrial cooling are:
Tab. 2: Water contaminants
Note:
The water circuit should be protected
from ingress of dirt or excess pressure
(maximum permitted operating pressure
10 bar)!
Note:
Observe the flow direction
and check for leaks!
Note:
The units do not have any separate
ventilation.
For pressure-sealed systems, install the
appropriate ventilation equipment on the
water side.
Contamination
of the water
Procedure
Mechanical
contamination
Filter the water using:
– Mesh filter
– Gravel filter
– Cartridge filter
– Precoated filter
Excessive hardness
Water softening
via ion exchange
Moderate content
of mechanical
contaminants and
hardeners
Addition of stabilisers
and/or dispersing agents
to the water
Moderate content of
chemical contaminants
Addition of passifiers
and/or inhibitors
to the water
Biological contaminants,
slime bacteria and algae
Addition of biocides
to the water
