Danfoss VLZ065, Инструкции по применению

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Oil temperature sensor must be placed between
oil sight glass and compressor baseplate. Some
thermal paste shall be used to improve the
conductivity. The sensor must also be correctly
thermally insulated from the ambiance.
The Oil superheat is defined as:
(Oil temperature - Evaporating temperature)
30
28
26
24
22
20
18
16
-25 -20 -15 -10 -5 0 5 10
14
Unacceptable
Acceptable
Evaporating Temperature (°C)
Oil Superheat (K
)
Danfoss
OE-000064
-13 -4 5 14 23 32 41 50
30
28
26
24
22
20
18
16
14
Evaporating Temperature (°F)
Oil Superheat (K
)
30
28
26
24
22
20
18
16
14
30
28
26
24
22
20
18
16
14
Unacceptable
Acceptable
Evaporating Temperature (°C)
Evaporating Temperature (°F)
Oil Superheat (K
)
Oil Superheat (K
)
Danfoss
OE-000065
-25 -20 -15 -10 -5 0 5 10
-13 -4 5 14 23 32 41 50
Manage superheat
Test, criteria and solutions
Test N° Purpose Test condition Pass criteria Solutions
Liquid flood
back test
Steady-state
Liquid flood back testing must be
carried out under expansion valve
threshold operating conditions:
•Lowest foreseeable evaporation,
and highest foreseeable
condensation.
•Minimum speed running.
For reversible system, perform test
in both heating and cooling mode Suction superheat >5K
1. Check expansion valve selection
and setting.
-For Thermostatic expansion valve
(TXV) check bulb position...
-For Electronic expansion valve
(EXV) check measurement chain and
PID....
2. Add a suction accumulator*.
Transient
Tests must be carried out with most
unfavorable conditions :
• fan staging,
• compressor staging
• …
Oil superheat shall not be more than
30 sec below the safe limit defined in
the Dilution Chart. (See graph above)
*Suction accumulator offers protection by trapping the liquid refrigerant upstream from the compressor. The accumulator should be sized at least 50 % of the total system
charge. Suction accumulator dimensions can impact oil return (gas velocity, oil return hole size…), therefore oil return has to be checked according to section “Manage oil in the
circuit”.
A
Dilution Chart with R404A Dilution Chart with R448A/R449A
27
AB444226142054en-000101