Danfoss DSH Series Application Guide

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Application
Manage oil in the circuit
Requirement
Oil level must be visible or full in the sight glass when the compressor is running and when all compressors of
the circuit are stopped. For DSH140-184 medium trio models, top-up oil quantity 1L at least as mandatory.
System evaluation
Table 26: Manage oil in the circuit - System evaluation
Split type
Single compressor
Manifold compressors
Non split
Test No.1
Test No.1+2
Split
Test No.1+3
Test No.1+2+3
Test, criteria and solutions
Table 27: Manage oil in the circuit - Test, criteria and solutions
Test No.
Purpose
Test conditions
Pass criteria
Solutions
1
Check proper oil
return
A
Lowest foreseeable evaporation, and
highest foreseeable condensation.
Minimum number of compressor run-
ning for 6 hours.
For reversible system, perform test in
both heating and cooling mode.
Oil level must be visible or full in the
sight glass when the compressor is run-
ning and when all compressors of the
circuit are stopped.
Top-up with oil, generally 3% of the
total system refrigerant charge (in
weight). Above 3% look for poten-
tial oil trap in the system.
Integrate a function in control logic
to run all compressors simultane-
ously in order to boost oil return
(for more details see section Con-
trol logic)
Oil separator can be added
2
Check oil balanc-
ing
A
Lowest foreseeable evaporation and
highest foreseeable condensation and
nominal capacity condition
for tandem 2 compressors running for 6
hours, for trio, compressor running fol-
low the running sequence:
(1+2+3)2hrs→ (1+2)2hrs →(2+3)2hrs→
(1+3)2hrs
For reversible system, perform test in
both heating and cooling mode.
Oil level must be visible or full in the
sight glass when the compressors are
running and when all compressors of
the circuit are stopped
Top-up with oil, generally 3% of the
total system refrigerant charge (in
weight).
Check that manifold piping is con-
form to Danfoss requirements.
Integrate a function in control logic
to stop manifold periodically in or-
der to balance oil (for more details
see section Control logic)
3
Oil return in split
systems
Since each installation is unique, test 1
and 2 can not fully validate the oil re-
turn. Oil level must be checked and ad-
justed at commissioning.
Oil level must be visible or full in the
sight glass when the compressor is run-
ning and when all compressors of the
circuit are stopped.
Pay special attention to “Piping de-
sign”
Oil separator is strongly recommen-
ded, espacially in case of part load.
Manage sound and vibration
Sound radiations
Mitigations methods: We can consider two means to reduce compressors sound radiations:
Acoustic hoods are quick and easy to install and do not increase the overall size of the compressors. Acoustic
hoods are available from Danfoss as accessories. Refer to the tables above for sound levels, attenuation and code
numbers.
Use of sound-insulation materials on the inside of unit panels is also an eective mean to reduce sound
radiation.
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Scroll compressors, DSH090 to DSH600 | Application

Danfoss DSH Series Specifications

General

Brand	Danfoss
Model	DSH Series
Category	Air Compressor
Language	English