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Instructions
to avoid damage.
• Field piping should be installed such that it will
be free from corrosive or salty environment to
avoid corrosion in copper /Aluminum piping.
• In case of fire incidence, pressure increases due
to increasing in temperature at receiver. Hence it
is very important to install the PRV.
9 – Filling the system
• Never start the compressor under vacuum. Keep
the compressor switched off.
• Use only the refrigerant for which the unit is de-
signed for.
• Fill the refrigerant in liquid phase into the
condenser or liquid receiver. Ensure a slow char-
ging of the system to 4 – 5 bar.
• The remaining charge is done until the installa-
tion has reached a level of stable nominal condi-
tion during operation.
• The charge must be as closed as possible to
the nominal system charge to avoid low pres-
sure operation and excessive superheat. For
VLZ028-044, the refrigerant charge limit is
3.6kg.Above this limit; protect the compressor
against liquid flood-back with a pump-down cy-
cle not lower than 2.3 bar (g) for R448A/R449A/
2.3 bar(g) for R407F / 2.3 bar(g) for R407A /
2.3 bar(g) for R404A / or a suction line accumulator.
• Never leave the filling cylinder connected to the
circuit.
• Suction, Liquid valves and Receiver Rotolock
valves as Schrader port for service operation like
Gas Charging, pressure measurement.
10 – Setting the electronic controller
• The unit is equipped with an electronic controller
which is factory programmed with parameters for
use with the actual unit. Refer to manual 158381
for details.
• By default, the electronic controller display shows
the temperature value for the suction pressure in
°C. To show the temperature value for the conden-
sing pressure, push the lower button (picture 2).
The electronic controller is factory preset for opera-
tion with refrigerant R449A. If another refrigerant is
used, the refrigerant setting must be changed. Pa-
rameter r12 must be set to 0 before (software main
switch= off).
• Push the upper button for a couple of seconds.
The first parameter code appears.
• Push the upper or lower button to find parameter
code o30.
• Push the middle button until the value for this pa-
rameter is shown.
• Push the upper or lower button to select the
new value: 17 = R507A, 19 = R404A, 21=R407A,
37=R407F, 40= R448A, 41= R449A.
•
R407A and R407F not applicable for OP-MP-
PM065 model.
• Push the middle button to confirm the selected
value.
• Go back to parameter r12 and change it to 1.
• If necessary change also parameter r23 to desired
suction pressure (°C/°F).
• Change parameter c33 for pump down value ac-
cording your needs.
• Push the middle button, default maximum
discharge temperature is 125°C
• If customer want to increase the valve, push the
upper button to select the new value: 130 push
middle button to confirm the selected value.
4 |AN18718642524203-000701 - 118A5499A
• Maximum allowable discharge temperature (r84)
should not exceed 130 °C
11 – Verification before commissioning
Use safety devices such as safety
pressure switch and mechanical re-
lief valve in compliance with both
generally and locally applicable regu-
lations and safety standards. Ensure
that they are operational and proper-
ly set.
Check that the settings of high-pres-
sure switches and relief valves don't
exceed the maximum service pressure
of any system component.
• Verify that all electrical connections are properly
fastened and in compliance with local regula-
tions.
• The crankcase heater must be energized at least
12 hours before initial start-up and start-up after
prolonged shutdown to remove refrigerant in
liquid phase from the compressor. Remove DI1
plug from the controller to avoid compressor
start and turn ON the main switch during this
period.
• The unit is equipped with a main switch with
overload protection. Overload protection is pre-
set from factory, but it is recommended to check
the value before taking the unit in operation. The
overload protection value can be found in the wi-
ring diagram in the unit front door.
• Suction, Liquid valves and Receiver Rotolock
valves as Schrader port for service operation like
Gas Charging, pressure measurement.
12 – Start-up
• Never start the unit when no refrigerant is
charged.
• All service valves must be in the open position.
• Check compliance between unit and power sup-
ply.
• Check that the crankcase heater is working.
• Check that the fan can rotate freely.
• Balance the HP/LP pressure.
• Energize the unit. It must start promptly. If the
compressor does not start, check wiring confor-
mity and voltage on terminals.
• Reverse rotation of the 3-phase compressor will
be detected from the controller and can be de-
tected by following phenomena; the compres-
sor doesn't build up pressure, it has abnormally
high sound level and abnormally low power
consumption. In such case, shut down the unit
immediately and connect the phases to their
proper terminals.
• If the rotation direction is correct the low pres-
sure indication on the controller (or low pressure
gauge) shall show a declining pressure and the
high pressure indication (or high pressure gauge)
shall show an increasing pressure.
13 – Check with running unit
• Check the fan rotation direction. Air must flow
from the condenser towards the fan.
• Check current draw and voltage.
• Check suction superheat to reduce risk of slug-
ging.
• The optimum compressor suction superheat is
around 6K. The maximum allowed superheat is
30K.
Observe the oil level at start and during operation
to confirm that the oil level remains visible. Excess
foaming in oil sight glass indicates refrigerant on
the sump.
• Monitor the oil sight glass for 1 hour after
system equilibrium to ensure proper oil re-
turn to the compressor. This oil check has to
be done over the speed range to guarantee:
- a good oil return at low speed with minimum
gas velocity.
- a good oil management at high speed with
maximum oil carry over.
• In installations with good oil return and line runs
up to 15 m (49 feet), no additional oil is required.
• If installation lines exceed 15 m (49 feet), additio-
nal oil may be needed. 1 or 2% of the total system
refrigerant charge (in kg) can be used to roughly
define the required oil top-up quantity (in liters)
but in any case, the oil charge has to be adjusted
based on the oil level in the compressor sight
glass.
• When the compressor is running under stabilized
conditions, the oil level must be visible in the
sight glass.
• The oil level can also be checked a few minutes
after the compressor stops, the level must be
between 1/4 and 3/4 of sight glass.
• Respect the operating limits.
• Check all tubes for abnormal vibration. Move-
ments in excess of 1.5 mm require corrective
measures such as tube brackets.
• When needed, additional refrigerant in liquid
phase may be added in the low-pressure side as far
as possible from the compressor. The compressor
must be operating during this process.
• Do not overcharge the system.
• Never release refrigerant to atmosphere.
• Before leaving the installation site, carry out a
general installation inspection regarding clean-
liness, noise and leak detection.
• Record type and amount of refrigerant charge
as well as operating conditions as a reference for
future inspections.
Compressor failure to build up pressure: Check all
bypass valves in the system to ensure that none of
these has been opened. Also check that all solenoid
valves are in their proper position.
• Abnormal running noise: Ensure the absence
of any liquid flood-back to the compressor by
means of measuring the return gas superheat
and compressor sump temperature. The sump
should be at least 6K above the saturated suc-
tion temperature under steady-state operating
conditions.
• The high-pressure switch trips out: Check
condenser operations (condenser cleanliness,
fan operation, water flow and water pressure
valve, water filter, etc.). If all these are OK, the
problem may be due to either refrigerant over-
charging or the presence of a noncondensable
(e.g. air, moisture) in the circuit.
• The low-pressure switch trips out: Check evapo-
rator operations (coil cleanliness, fan operations,
water flow, water filter, etc.), liquid refrigerant
flow and pressure drops (solenoid valve, filter
dryer, expansion valve, etc.), refrigerant charge.
• Low refrigerant charge: The correct refrigerant
charge is given by the liquid sight glass indica-
tion, the condenser delta T in relation to the re-
frigerant pressure tables (pressuretemperature),
© Danfoss | Climate Solutions | 2024.06
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