Minimum/maximum medium flow
The chiller`s circulation pump gen-
erates a constant medium flow;
the result is a loss of pressure in
the system and in the chiller. The
differential pressure switch in the
chiller measures the medium pres-
sure loss over the evaporator and
switches the unit off if the mini-
mum flow volume is undercut.
The medium flow limit may like-
wise not be exceeded (maximum
flow volume).
A 3-way valve with bypass and
a hydraulic switch to establish a
primary and secondary circuit or
a volume dependent bypass are
necessary to ensure a constant
flow volume.
Minimum medium volume, of the
system
As a consequence of the adaptive
controller a storage tank is not
mandatory. However, the mini-
mum medium volume may not be
fallen short of in order to ensure
fault-free operation of the unit.
individual pressure losses of each
individual unit in the pipeline
network design must be adjusted
to the entire system. The nomi-
nal flow volumes for the medium
adjust to the necessary values as
a consequence of the pressure loss.
Valves for hydronic balancing
Through valves for hydronic bal-
ancing to be installed on-site,
Medium piping
Medium piping can be made of
copper, steel or plastic. To minimise
pressure losses, only streamlined
fittings should be used.
When designing the layout, the
large flow volumes in cold wa-
ter systems, high pressure losses
in connection with water-glycol
mixtures and the chiller's minimum
flow volume must be taken into
account.
The lines are to be insulated
against vapour diffusion and,
if necessary, the current Energy-
Savings-Ordinance (EnEV) must to
be observed. UV resistance must
be realised outdoors.
During use and
disposal the product and safety
data sheets of the glycol type
which is used must be ob-
served.
!
CAUTION
Propor-
tion
glycol
Frost
protection
+-2°C
Correction factors when using a
mixture of glycol * and water
Cooling
capacity
Compressor capacity
Cooling Heating
Flow
volume
Pressure
loss
Vol. %
°C
K
L
K
P cooling
K
P heating
K
V
K
D
0
0
1
1
1,012
1
1
20
-9
0,981
0,988
1,012
1,040
1,19
35
-21
0,971
0,982
1,018
1,090
1,35
40
-26
0,968
0,981
1,019
1,105
1,51
Use the required type and
mixture to ensure the freezing
point.
!
CAUTION
*
We recommend using an ethylene glycol mixture. Observe the safety and
product data sheets for the glycol type being used.
Frost protection (accessories)
As a medium for a cold water
system, a water-glycol mixture
is used as a rule. Depending on
the use to which the glycol type
and quantity is put, the viscos-
ity changes, the loss in pressure
increases and the unit's cooling or
heating capacity reduces. All sys-
tem components must be ap-
proved for use with glycol.
As a rule, the addition to the water
of ethylene glycol, in a proportion
of 34%, with inhibitors for corro-
sion protection is recommended.
This concentration ensures anti-
freeze protection to –20°C; at lower
temperatures, an ice porridge forms
which has no explosive effect.
The toxicologically harmless
propylene glycol should be used if
there is a risk that the medium can
come into contact with drinking
water or food stuffs. To inhibit the
explosive effects, a proportion of
38% is necessary as a rule.
To regulate the circulation pump
we recommend a main
pipe regulating valve near the unit.
NOTE
Pressure gauge and thermometer
The pressure gauge and thermom-
eter to be installed on-site at
the intake and outlet serve to set
the medium flow. The display
should mean shut down In the
system there are temperature
sensors in the medium intake and
medium outlet.
The temperature at the probes can
be seen on the controller.
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