Danfoss VZH088-G single User Manual

Operating conditions
Discharge line
Insulation
Bracket
Thermostat
Insucient oil level can be the result of oil
depositing itself in pipes and heat exchangers.
The oil deposit can be returned to the crankcase,
by increasing velocity for short periods, at
regular time intervals or when velocity is too low
to ensure adequate oil returns.
With oil return management these two oil return
mechanisms can be programmed in the CDS303.
With oil return management function enabled,
the CDS303 performs oil return by boosting the
compressor speed to 4200 rpm (70 rps) for a
selectable duration as programmed in parameter
28.13. The boosts are performed at xed time
intervals (as programmed in parameter 28.12) or
if the compressor speed has been less than 3000
rpm (50 rps) for too long (as programmed in
28.11) whichever occurs rst. Thus the maximum
time between two consecutive oil return boosts
is programmed in 28.12.
Considering oil return risk, split system
with more than 10m piping length need
mandatory application approval by Danfoss
application specialists.
Use the accessory “oil level switch” with the
appropriate compressor housing having the
tting preassembled and refer to the VZH hybrid
manifold guideline (FRCC.PC.049).
Oil return management
function (single
compressor)
Oil return management
in hybrid manifolding
The discharge gas temperature must not exceed
135°C.
A discharge gas temperature protection device
must be installed on all heat pumps. In reversible
air-to-air and air-to-water heat pumps the
discharge temperature must be monitored
during development test by the equipment
manufacturer.
The compressor must not be allowed to cycle
on the discharge gas thermostat. Continuous
operations beyond the compressor’s operating
range will cause serious damage to the
compressor!
A DGT accessory is available from Danfoss: refer
to accessories pages at the end of this document.
The discharge gas thermostat accessory kit (code
no.7750009) includes all components required
for installation, as shown below. The thermostat
must be attached to the discharge line within
150 mm from the compressor discharge port and
must be thermally insulated and tightly xed on
the pipe.
ID Name
Factory
Setup
"long pipe
(25-30m)"
Unit
2810
Oil Return
Management
On On
2811
Low Speed
Running Time
60 30 min
2812
Fixed Boost
Interval
24 6 h
2813 Boost Duration 30 60 s
High and low pressure
protection
High pressure According to EN378-2, a high-pressure (HP) safety
switch is required to shut down the compressor.
The high-pressure switch can be set to lower
values depending on the application and
ambient conditions. The HP switch must either be
placed in a lockout circuit or consist of a manual
reset device to prevent cycling around the high-
pressure limit. If a discharge valve is used, the HP
switch must be connected to the service valve
gauge port, which must not be isolated. The HP
switch must be connected to the CDS303 input
37 or an external contactor placed between the
drive and the compressor.
43FRCC.PC.023.A8.02
Application Guidelines

Danfoss VZH088-G single Specifications

General

Brand	Danfoss
Model	VZH088-G single
Category	Air Compressor
Language	English