Danfoss SH090 Application Guidelines

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FRCC.PC.007.B8.02
Application guidelines
Installation
In installations with good oil return and line
runs up to 20 m, no additional oil is required. If
installation lines exceed 20 m, additional oil may
be needed. 1 or 2% of the total system refrigerant
charge (in weight) can be used to rou
ghly de ne
the required oil top-up quantity 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 presence of foam  lling in the sight glass
indicates large concentration of refrigerant in the
oil and / or presence of liquid returning to the
compressor.
The oil lev
el can also be checked a few minutes
after the compressor stops.
When the compressor is o , the level in the
sight glass can be in uenced by the presence of
refrigerant in the oil.
Always use original Dan
foss POE oil 160SZ from
new cans.
Top-up the oil while the compressor is idle. Use
the schrader connector or any other accessible
connector on the compressor suction line and
a suitable pump. See News bulletin «Lubricants
 lling in instr
uctions for Danfoss Commercial
Compressors».
Oil level checking and
top-up
The system must be monitored after initial start-
up for a minimum of 60 minutes to ensure proper
operating characteristics such as:
• Proper metering device operation and desired
superheat readings
• Suction and discharge pressure are
within
acceptable levels
• Correct oil level in compressor sump indicating
proper oil return
• Low foaming in sight glass and compressor
sump temperature 10K above saturation
temperature to show that there is no
refrigerant migration taking place
• Acceptable cycling rate of compressors,
including duration of run times
• Current draw of individual compressors within
acceptable values (max operating current)
• No abnormal vibrations and noise.
Commissioning
Insulation resistance and
dielectric strength
Insulation resistance must be higher than 1
megohm when measured with a 500 volt direct
current megohm tester.
Each compressor motor is tested at the factory
with a high potential voltage (hi-pot) that
exceeds the UL requirement both in potential
an
d in duration. Leakage current is less than 0.5
mA.
SH scroll compressors are con gured with
the pump assembly at the top of the shell,
and the motor below. As a result, the motor
can be partially immersed in refrigerant and
oil. The presence
of refrigerant around the
motor windings will result in lower resistance
values to ground and higher leak age current
readings. Such readings do not indicate a faulty
compressor.
In testing insulation resistance, Danfoss
recommends
that the system be  rst operated
brie y to distribute refrigerant throughout the
system. Following this brief operation, retest the
compressor for insulation resistance or current
leakage.
Never reset a breaker or replace a fuse withou
t
 rst checking for a ground fault (a short circuit to
ground). Be alert for sounds of arcing inside the
compressor.
For the initial charge the compressor must not
run and eventual service valves must be closed.
Charge refrigerant as close as possible to the
nominal system charge before starting the
compressor. This initial charging o
peration must
be done in liquid phase. The best location is on
the liquid line between the condenser outlet
and the  lter drier. Then during commissioning,
when needed, a complement of charge can be
done in liquid phase: slowly
throttling liquid in
on the low pressure side as far away as possible
from the compressor suction connection while
compressor is running. The refrigerant charge
quantity must be suitable for both summer and
winter o
perations.
Vacuum or charge from one side can seal the
scrolls and result in a non-starting compressor.
When servicing, always ensure that LP/HP
pressures are balanced before starting the
compressor.
Be sure to foll
ow all government regulations
regarding refrigerant reclamation and storage.
For more detailed information see "Recom-
mended refrigerant system charging practice"
news bulletin FRCC.EN.050.
Refrigerant charging

Danfoss SH090 Specifications

General

Brand	Danfoss
Model	SH090
Category	Air Compressor
Language	English