Dimplex LAB 07M, Инструкция по установке и эксплуатации

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www.dimplex.de EN-15
13.1
Englis
h
12.4 Hydraulic cicuit controls
„ Check that the heating system has been flushed and the
washing water drained out before the unit is connected to
the system.
„ Check that all the hydraulic connections have been made
correctly and that the specifications on the rating plates have
been followed.
„
Check that the hydraulic system is filled and under pressure
and also make sure that no air is present; if so, bleed it.
„ Check to make sure that any cut-off valves in the system are
correctly opened.
„ The anti-freeze control managed by the electronic regulation
and by the temperature probe located at the outlet of the
evaporator is to prevent the formation of ice when the water
flow rate is too low. Correct operation can be checked by
progressively increasingly the anti-freeze set-point until it
passes the outlet water temperature and keeping the water
temperature controlled with a high precision thermometer,
verify that the unit is off and generates the respective alarm.
After this operation, take the anti-freeze set-point back to its
original value.
12.5 Refridgeration circuit controls
„ Check the refrigeration circuit for any oil spots which would
indicate possible leaks (caused by transport, handling, or
other)
„ Check the refrigeration circuit for any oil spots which may be
a sign of leaks (caused by transport, handling, or other)
„ Verify that the refrigeration circuit is pressurised.
„ Check that all the refrigeration service outlets are closed
with caps; their absence could cause refrigerant leaks.
12.6 Refridgeration circuit checks
Check for any refrigerant gas leaks particularly around pressure
plugs, pressure transducers and pressure switches. Vibrations
during transportation may have loosened the connections.
12.7 System loading/unloading
During the winter period, in the event of the system pause, the
water in the condenser can freeze, causing irreparable damage
to the condenser itself, the complete discharge of the refridgera-
tion circuits and, at times, damage to the compressors.To pre-
vent the danger of the hydraulic circuit freezing, the following so-
lutions are possible.
Circuit without glycol:
„ Complete discharge of the water from the heat exchanger at
the end of the season and re-filling at the start of the succes-
sive season, by means of a discharge valve, which must be
installed by the installer.
„ Using the heat exchanger heating resistances (accessory).
In this case the resistances must always be supplied with
electrical power for the entire period of possible freezing
(machine in stand-by).
Circuit with glycol:
„ Operation with glycol/water fluid, with a percentage of glycol
chosen based on the minimum outdoor temperature ex-
pected. In this case you must take into account the different
outputs and absorption of the chiller, the sizing of the
pumps, and the output of the terminals.
13 Ethylene glycol
solutions
„ The correction factors of cooling power and input power take
into account the presence of glycol and diverse evaporation
temperatures.
„ The pressure drop correction factor considers the different
flow rate resulting from the application of the water flow rate
correction factor.
„ The water flow rate correction factor is calculated to keep
the same
Δ
t that would be present with the absence of gly-
col.
NOTE
On the following page an example is given to help graph reading.
To determine the percentage of glycol required, see below dia-
gram; this percentage calculation can take into consideration one
of the following factors: Depending on which fluid is considered
(water or air), the graph is interpreted by the right or left side at
the crossing point on the curves with the external temperature
line or the water produced line. A point from which the vertical
line will pass is obtained and this will distinguish both glycol per-
centage and relative correction coefficients.
13.1 How to read the glycol curves
The curves shown in the diagram summarise a significant
number of data, each of which is represented by a specific curve.
In order to use these curves correctly it is first necessary to make
some initial reflections:
„ If you wish to calculate the percentage of glycol on the basis
of the external air temperature, enter from the left axis and
on reaching the curve draw a vertical line, which in turn will
intercept all the other curves; the points obtained from the
upper curves represent the coefficients for the correction of
the cooling capacity and input power, the flow rates and the
pressure drops (remember that these coefficients must be
multiplied by the nominal value of the size in question); while
the glycol percentage value recommended to produce de-
sired water temperature is on the lower axis.
„ If you wish to calculate the percentage of glycol on the basis
of the temperature of the water produced, enter from the
right axis and on reaching the curve draw a vertical line,
which in turn will intercept all the other curves; the points ob-
tained from the upper curves represent the coefficients for
the cooling capacity and input power, the flow rates and the
pressure drops (remember that these coefficients must be
multiplied by the nominal value of the size in question); while
the glycol percentage value recommended to produce water
at the desired temperature nominal of the size in question;
while the lower axis recommends the glycol percentage
value necessary to produce water at the desired tempera-
ture.