Danfoss VZH hybrid manifold Application guide

Application guidelines

Inverter scroll compressors

VZH hybrid manifold

R410A

http://cc.danfoss.com

Contents

GENERAL INFORMATION ....................................................................................................4

Scope ...................................................................................................................................................................................... 4

Benets .................................................................................................................................................................................. 4

PRODUCT INFORMATION ...................................................................................................5

Oil management concept ....................................................................................................5

System conguration .......................................................................................................................................................5

Dimensions ...........................................................................................................................8

Tandem .................................................................................................................................................................................. 8

SYSTEM DESIGN ...................................................................................................................9

Design pipe ...........................................................................................................................9

General requirements ...................................................................................................................................................... 9

Suction separator .............................................................................................................................................................11

Oil equalization design .................................................................................................................................................. 11

Design compressor mounting ..........................................................................................12

General requirements ....................................................................................................................................................12

VZH178 Mounting feet ...................................................................................................................................................12

VZH208 Mounting feet ..................................................................................................................................................12

VZH257 / VZH278 Mounting feet ...............................................................................................................................12

VZH301 Mounting feet...................................................................................................................................................13

VZH350 / VZH410 / VZH465 Mounting feet ........................................................................................................... 13

VZH354 Mounting kit ..................................................................................................................................................... 13

Manage operating envelope .............................................................................................14

Requirement ...................................................................................................................................................................... 14

Manage superheat .............................................................................................................15

Requirement ...................................................................................................................................................................... 15

System evaluation ...........................................................................................................................................................15

Test, criteria and solutions ............................................................................................................................................ 15

Manage o-cycle migration ..............................................................................................17

Requirement ...................................................................................................................................................................... 17

System evaluation ...........................................................................................................................................................17

Refrigerant charge limit table ..................................................................................................................................... 17

Manage oil in the circuit ....................................................................................................18

Oil management system for hybrid manifolding ................................................................................................18

Oil management logic ...................................................................................................................................................18

Requirement ...................................................................................................................................................................... 19

System evaluation ...........................................................................................................................................................19

Test, criteria and solutions ............................................................................................................................................ 19

Control logic ...................................................................................................................... 20

Safety control logic requirements .............................................................................................................................20

Cycle rate limit requirements ......................................................................................................................................20

Defrost logic recommendations ................................................................................................................................20

Pump-down logic recommendations ......................................................................................................................21

Assembly line procedure .................................................................................................. 22

Handling ..............................................................................................................................................................................22

ORDERING INFORMATION .............................................................................................. 23

Compressor ordering codes ........................................................................................................................................23

Accessory ordering codes .............................................................................................................................................23

Accessories ......................................................................................................................... 24

Annex ................................................................................................................................. 26

3FRCC.PC.049.A3.02

General information

Scope

Benets

The application guideline describes the operating
characteristics, design features and application
requirements for hybrid manifolding of the
Danfoss SH xed-speed compressor and the VZH
inverter compressor in air-conditioning and heat
pump applications.

To ensure proper parallel installation and running
conditions, the following recommendations must
be followed:

A parallel compressor installation refers to a
system of interconnected compressors with a
common suction line and a common discharge
line. The technique of mounting compressors
in parallel is also called manifolding. The hybrid
manifolding in this application guideline refers
to the manifolding of the Danfoss inverter
compressor (VZH) and xed speed compressor
(SH), which has several benets.

• It is essential to respect all the instructions
given in these guidelines; please refer to
the instruction leaet supplied with each
compressor and the application guidelines for
single compressors.

• For additional system components related to
specic application requirements, the supplier
recommendations must always be respected.

The main reason is reduced operating cost
through controlling capacity and power
consumption to a greater extent. This is achieved
by both staggering the compressor switch-on
sequences and regulating the speed of the
inverter compressor which allows the parallel
system to continuously match its power with the
capacity needed.

PRODUCT INFORMATIONSYSTEM DESIGNORDERING INFORMATION GENERAL INFORMATION

Capacity

Compressor n°1

VZH 25-100 rps

A second reason for manifolding the inverter
compressor and the xed speed compressor is
improved part-load eciency. In the variable
speed+xed speed parallel installation,
the system can run either only the inverter
compressor at lower load or both the inverter and
xed speed compressors at a higher load with the
xed speed compressor operating at 100% load.

Compressor n°1

VZH 25-100 rps

Compressor n°2

xed speed SH

Therefore, it will be possible to achieve a higher
part-load eciency.

Thirdly, the capacity of the hybrid manifolding
system can be widely regulated, for example 10%
to 100%. The continuous capacity regulation
allows for accurate temperature control and a
comfortable indoor environment.

4 FRCC.PC.049.A3.02

Oil management concept

System conguration

Hybrid manifolding systems use the dynamic
system for oil balance. The suction connections
between the two individual compressors are
interconnected by a special suction separator
design that allows most of oil feed into variable
speed compressors.

Discharge line

VZH

SH

An optical-electrical oil level sensor xed in
a variable speed compressor monitors the
compressor oil level.

If the oil level drops below the limit, the OEM
main controller activates the oil management
logic.

Drive

ModBus

OEM main controller

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

Oil equalization tube

Optical oil
level sensor

Suction separatorSuction line

5FRCC.PC.049.A3.02

Oil management concept

FS VS

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

Downstream
compressor

Upstream
compressor

Suction separator (Oil separator/gas restrictor)

The hybrid manifolding system uses the dynamic
system for oil balance.

The suction connections of the two individual
compressors are interconnected by a suction
separator that integrates with the suction oil
separator and the gas restrictor. The variable
speed compressor (VS) is installed in the
upstream position which appears rst on suction
line and xed speed compressor (FS) is installed
on downstream position.

The oil which clings back along the main suction
line is separated by the suction separator which

returns most of the oil in the suction gas to the
upstream compressor. The suction separator
creates a slight pressure drop to ensure lower
sump pressure between two compressors are
well balance when xed speed compressor
is ON and the inverter compressor is running
at maximum speed. When the variable speed
compressor runs at any frequency below
maximum speed, the sump pressure in the xed
speed compressor is lower than the variable
speed compressor, and driven by the sump
pressure dierence, the excess oil from the
variable speed compressor runs into the xed
speed compressor sump.

6 FRCC.PC.049.A3.02

Oil management concept

Approved hybrid tandem
congurations and
capacity range

Dierent congurations of hybrid tandems are possible. All VZH models (high/low pressure ratio/
dierent voltage) could be manifolded with xed speed compressors.

Danfoss VSD : VZH compressor DriveTM 380-480 Volt

Model Description

VZH178 VZH088+SH90 68.9 19.6 73.9 21.0
VZH208 VZH088+SH120 77.7 22.1 83.7 23.8
VZH257 VZH117+SH140 97.8 27. 8 105. 2 29.9
VZH278 VZH117+SH161 101.6 28.9 110 .1 31.3
VZH301 VZH117+SH184 106.2 30.2 115 .7 32.9
VZH350 VZH170+SH180 137. 5 39.1 147. 4 41.9
VZH354 VZH170+SH184 137. 0 39.1 146 .0 41.9
VZ H410 V ZH170+SH240 151.9 43.2 164.9 46.9
VZH465 V ZH170 +SH295 164.6 46.8 179. 3 51.0

TR: Ton of Refrigeration Refrigerant: R410A

Standard rating conditions: ARI standard Evaporating temperature: 7.2°C Superheat: 11.1k

Condensing temperature: 54.4°C Subcooling: 8.3k

Subject to modication without prior notication

Data given for motor code G compressor – for full data details and capacity tables, please refer to Coolselector2

www.coolselector.danfoss.com

FS: 50Hz, VS:100Hz FS: 60Hz, VS: 100Hz

kW TR kW TR

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

7FRCC.PC.049.A3.02

Dimensions

Tandem

 

H

GENERAL INFORMATIONSYSTEM DESIGNORDERING INFORMATION PRODUCT INFORMATION

D

L

Tandem model Composition

VZH178 VZH088 + SH090

Outline drawing

number




VZH208 VZH088 + SH120




VZH257 VZH117 + SH140




VZH278 VZH117 + SH161




VZH301 VZH117 + SH184




VZH350 VZH170 + SH180




VZH354 VZH170 + SH184




VZ H410 VZH170 + SH240




VZH465 VZH170 + SH295




Tandem congurations are achieved by assembling individual compressors

H

D

L

Suction Discharge L (mm) D (mm) H (mm)

8560108 1"5/8 1"3/8 1011 445 482

8560109 1"5/8 1"3/8 810 445 482

8560104 1"5/8 1"3/8 1011 445 540

8560105 1"5/8 1"3/8 811 445 540

8560106 1"5/8 1"3/8 1024 445 540

8560107 1"5/8 1"3/8 811 445 540

8560106 1"5/8 1"3/8 1024 445 540

8560107 1"5/8 1"3/8 811 445 540

8556183 1"5/8 1"3/8 1116 445 555

8556184 1"5/8 1"3/8 811 445 555

8556181 2"1/8 1"5/8 1233 550 682

8556182 2"1/8 1"5/8 953 550 682

8556188 2"1/8 1"5/8 1241 550 682

8556189 2"1/8 1"5/8 890 550 682

8556181 2"1/8 1"5/8 1233 550 682

8556182 2"1/8 1"5/8 953 550 682

8556181 2"1/8 1"5/8 1233 550 682

8556182 2"1/8 1"5/8 953 550 682

8 FRCC.PC.049.A3.02

Design pipe

General requirements Proper piping practices should be employed to:

1. Ensure adequate oil return, even under
minimum load conditions (xed speed
compressor o, variable speed compressor
at minimum speed, minimum evaporating
conditions). If minimum refrigerant velocity
cannot be reached, it is strongly recommended
that an oil separator is used. For a validation test,
the see section “Manage oil in the circuit”.

0.5% slope

4 m/s or more

max. 4 m

U-trap, as short as possible

8-12 m/s

max. 4 m

0.5% slope

4 m/s or more

2. Prevent condensed liquid refrigerant from
draining back into the compressor when
stopped (discharge piping upper loop). For
validation tests, see the section “Manage o-cycle
migration”.

General recommendations are described in the
gures below:

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

To condenser

HP

LP

Evaporator

U trap, as short as possible

Upper loop

HP

LP

3D exibility

3. Piping should be designed with adequate
three-dimensional exibility to avoid excess
vibration. It should not be in contact with the
surrounding structure, unless a proper tubing
mount has been installed. For more information

Condenser

on noise and vibration, see the section “Sound
and vibration management” in the application
guideline for Danfoss VZH scroll compressors
(FRCC.PC.023).

9FRCC.PC.049.A3.02

Design pipe

Suction on left Suction on right

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Variable speedVariable speed

Fixed speed Fixed speed

Fixed speed Variable speed Tandem model Suction direction

SH090 VZH088 VZH178 Left/Right

SH120 VZH088 VZH208 Left/Right

SH14 0 VZ H117 VZH257 Left/Right

SH161 V ZH117 VZH278 Left/Right

SH184 V ZH117 VZH301 Left/Right 50 & 60 120Z0 656

SH180 VZH170 VZH350 Left/Right 50 & 60 120Z0657

SH184 VZH170 VZH354

SH240 VZH170 VZH410 Left/Right 50 & 60 120 Z06 57

SH295 VZH170 VZH465 Left/Right 50 & 60 120 Z0655

Note:
The tandem accessory includes oil equalization kits and oil level sensor. For compressors that need a UL certicate, please order the accessory kit with the 24V oil level sensor.

+

+

+

+

+

+

Left

+

Right

+

+

Hz of FS

compressor

50 120Z0 676

60 12 0Z0675

50 120Z0664

60 120Z0658

50 120Z0666

60 120Z066 5

50 120Z 066 5

60 120Z0 674

50

60

50

60

Suction separator

code

120Z0683 120Z0682 (with 24V oil level sensor)

120Z0683 120Z0681 (with 230V oil level sensor)

120Z0 655 120Z0682 (with 24V oil level sensor)

120Z0 655 120Z0681 (with 230V oil level sensor)

120Z0 687 120Z0682 (with 24V oil level sensor)

120Z0 687 120Z0681 (with 230V oil level sensor)

120Z0 687 120Z0682 (with 24V oil level sensor)

120Z0 687 120Z0681 (with 230V oil level sensor)

Tandem accessory kit code

120Z0653 (with 24V oil level sensor)

120Z0654 (with 230V oil level sensor)

120Z0653 (with 24V oil level sensor)

120Z0654 (with 230V oil level sensor)

120Z0651 (with 24V oil level sensor)

120Z0652 (with 230V oil level sensor)

120Z0651 (with 24V oil level sensor)

120Z0652 (with 230V oil level sensor)

120Z0653 (with 24V oil level sensor)

120Z0654 (with 230V oil level sensor)

120Z0653 (with 24V oil level sensor)

120Z0654 (with 230V oil level sensor)

120Z0653 (with 24V oil level sensor)

120Z0654 (with 230V oil level sensor)

120Z0653 (with 24V oil level sensor)

120Z0654 (with 230V oil level sensor)

120Z0651 (with 24V oil level sensor)

120Z0652 (with 230V oil level sensor)

120Z0649 (with 24V oil level sensor)

120Z0650 (with 230V oil level sensor)

120Z0649 (with 24V oil level sensor)

120Z0650 (with 230V oil level sensor)

120Z0649 (with 24V oil level sensor)

120Z0650 (with 230V oil level sensor)

10 FRCC.PC.049.A3.02

Design pipe

Suction separator

Oil equalization design

The suction connections of the two individual
compressors are interconnected by a suction
separator, which is supplied as an accessory.

The two compressors are connected by a ½" or
¾" oil equalization pipe. To x the oil equalization
connection rotolock, use the adaptor sleeves

½"

Suction separator

and the seal gasket which were included in the
tandem accessory kit.

Model: VZH178-208-257-278-301/354
(SH184 oil equalization line)

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Tightening torque 100NM

Model: VZH350-410-465/354
(VZH170 oil equalization line)

¾"

Tightening torque 145Nm

Supplied with the compressor
Included in tandem kit
Not supplied

Supplied with the compressor
Included in tandem kit
Not supplied

11FRCC.PC.049.A3.02

Design compressor mounting

Tightening torque

General requirements

VZH178 Mounting feet

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

VZH208 Mounting feet

The tandem is xed to the frame using the
exible grommets that are supplied with

The compressors are xed to the frame using
rubber grommets, mounting sleeves, and
washers (supplied with the compressors).

HM 8 bolt

Lock washer

Flat washer

Steel mounting
sleeve

Rubber grommet

Nut

Base plate, frame, etc. with sucient rigidity

Mounting for SH090 and VZH088

15Nm

15 mm

The compressors are xed to the frame using
rubber grommets, mounting sleeves, and
washers (supplied with the compressors).

Because VZH088 is 7 mm smaller than SH120,
in order to ensure that the oil equalization

Tightening torque

HM 8 bolt

Lock washer

Flat washer

Steel mounting
sleeve

Rubber grommet

15Nm

15 mm

the compressor or which are included in the
accessory kit.

connection is at the same level for both
compressors, an additional 7mm rigid spacer
must be added under VZH088 (see drawing. The
7 mm rigid spacer is supplied with the tandem
accessory kit).

Tightening torque
15Nm

Rigid spacer

VZH257 / VZH278
Mounting feet

Nut

Base plate, frame, etc. with sucient rigidity

Mounting for SH120

The compressors are xed to the frame using
rubber grommets, mounting sleeves, and
washers (supplied with the compressors).

Tightening torque

HM 8 bolt

Lock washer

Flat washer

Steel mounting
sleeve

Rubber grommet

Nut

Base plate, frame, etc. with sucient rigidity

Mounting feet

15Nm

15 mm

Mounting for VZH088

12 FRCC.PC.049.A3.02

Design compressor mounting

Tightening
torque 21Nm

28mm

HM8 bolt

VZH301 Mounting feet

VZH350 / VZH410 /
VZH465 Mounting feet

The compressors are xed to the frame using
rubber grommets, mounting sleeves, and
washers (supplied with the compressors).

Because VZH117 is 7 mm smaller than SH184,
in order to ensure that the oil equalization

Tightening torque

HM 8 bolt

Lock washer

Flat washer

Steel mounting
sleeve

Rubber grommet

Nut

Base plate, frame, etc. with sucient rigidity

Mounting for SH184

15Nm

15 mm

The compressors are xed to the frame using
rubber grommets, mounting sleeves, and
washers. The VZH mounting kits are supplied

connection is at the same level for both
compressors, an additional 7mm rigid spacer
must be added under VZH117 (see drawing. The
7 mm rigid spacer is supplied with the tandem
accessory kit).

Tightening torque
15Nm

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Rigid spacer

Mounting for VZH117

with the VZH compressor, and SH mounting kits
are included in the tandem accessory kit.

VZH354 Mounting kit

Tightening

HM 8 bolt

Lock washer

Flat washer

Steel mounting sleeve

Rubber grommet

Nut

Mounting feet

torque 21Nm

Compressor
base plate

28 mm

The compressors are xed on the frame using
rubber grommets, mounting sleeves, washers
(delivered with the compressors).

Tightening
torque 15Nm

Lock washer

Steel mounting
sleeve

Nut

HM8 bolt

Flat
washer

Rubber
grommet

Rigid
spacers

Because SH184 is 14mm smaller than VZH170, in
order to have oil equalization connection at the
same level for both compressors, two additional
7mm rigid spacers must be added under SH184
(See below drawing, two 7mm rigid spacers are
provided in Tandem accessory kit).

HM8 bolt

Tightening
torque 21Nm

28mm

Base plate, frame, etc. with enough rigidity

Mounting for SH184 Mounting for VZH170

13FRCC.PC.049.A3.02

Manage operating envelope

Requirement The operating envelope for hybrid manifolding is

shown below, and guarantees reliable operation
of the compressor for steady-state operation.

VZH operating map - 575V/400V/208V (SH 6 K)

75

65

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

55

45

35

25

Condensing temperature (°C)

15

-30 -20 -10 0 10 20

30-90 rps

Evaporating temperature (°C)

High PR Low PR

The steady-state operation envelope is valid for a
suction superheat of between 5K and 30K.

30-90 rps

25-100 rps

Note: red and blue lled area are limited to 30-90 rps

Note: for 380V power input, permitted highest condensing temperature will decrease accordingly:

-High PR: 25-100 rps, condensing temperature from 60°C to 56°C; 30-90 rps, condensing temperature from 68°C to 65°C

-Low PR: 25-100 rps, condensing temperature from 60°C to 56°C; 30-90 rps, condensing temperature from 63°C to 62°C.

Pressure settings R410A

Working range high side bar(g)

Working range low side bar(g) 2.3-11.6

Maximum high pressure safety switch setting* bar(g) 45

Minimum low pressure safety switch setting bar(g) 1.5

Minimum low pressure pump-down switch setting bar(g)

*Maximum allowable pressure on high pressure side according to PED regulation.
LP and HP safety switches must never be bypassed nor delayed and must stop all the compressors.
The LP safety switch auto restart must be limited to ve times within 12 hours.
The HP safety switch must be reset manually.
Depending on application operating envelope, it is necessary to dene the HP and LP limits within the operating envelope and using
the pressure setting table above.

pressure with minimum of 2.3 bar(g)

High PR 13.5-44.5

Low PR 13.5-40

1.5 bar below nominal evaporating

14 FRCC.PC.049.A3.02

Manage superheat

Requirement

System evaluation

Basic unit

single exchanger

as evaporator and

condenser

X X Optional Pass liquid ood back test

X - X Recommended

During normal operation, refrigerant enters the
compressor as a superheated vapour. Liquid
ood back occurs when some of the refrigerant
entering the compressor is still in a liquid state.

In the steady-state condition, the expansion
device must ensure a suction superheat of
between 5k and 30k.

Advance unit

Multiple exchangers as evaporator or

condenser (heat-recovery, exchanger,

four-pipe chiller…)

X X Mandatory Pass liquid ood back test

X X Mandatory

Liquid ood back can cause oil dilution and, in
extreme situations, lead to liquid slugging that
can damage compression parts.

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Tes t

Non-reversible

Reversible

Suction accumulator

Pass liquid ood back test

Pass defrost test

Pass liquid ood back test

Pass defrost test

Test, criteria and solutions

Tes t N o Purpose Test condition Pass criteria Solutions

Liquid ood back testing must be
carried out under expansion valve
threshold operating conditions:

Variable speed On at min.speed /
xed speed O

Running conditions corresponding
to the lowest foreseeable
evaporation, and highest
foreseeable condensation

In case of reversible system, the test
must be done in both cooling and
heating mode
If advanced unit, test in all possible
congurations

Tests must be carried out in the
most unfavourable conditions:

• fan staging

• compressor ramping up and down

The defrost test must be carried out
in the most unfavorable conditions
(at 0°C evaporating temperature)

Suction superheat >5k

The oil superheat must not be more
than 30 sec below the safe limit
dened in the dilution chart (see
graph below)

The oil superheat must not be more
than 30 sec below the safe limit
dened in the dilution chart (see
graph below)

1. Check expansion valve selection
and setting
(EXV) check measurement chain and
PID.

2. Add a suction accumulator*

1. In reversible systems, the defrost
logic can be worked out to limit the
liquid ood back eect. (For more
details see “Control logic”)

2. Add a suction accumulator*

Liquid ood
back test

Defrost test

Steady-state

Transient

Check liquid
ood back
during defrost
cycle

* A suction accumulator oers protection by trapping the liquid refrigerant upstream from the compressor. The accumulator should be
sized at least 50% of the total system charge. The suction accumulator dimensions can impact oil return (gas velocity, oil return, hole size
etc.), and therefore the oil return has to be checked according to the “Manage oil in the circuit” section.

15FRCC.PC.049.A3.02

Manage superheat

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

The oil temperature sensor
must be placed between the oil
sight glass and the compressor
baseplate for xed speed
compressor, and beside the oil
level sensor for the variable speed
compressor.
Use a little thermal paste to
improve conductivity. The sensor
must also be thermally insulated
correctly from the ambience.

Oil superheat is dened as:
(Oil temperature - Evaporating temperature)

Dilution chart

18

17

16

Safety area

15

14

13

12

Oil superheat (K)

11

10

9

8

-25 -20 -15 -10 -5 0510 15

Evaporating temperature °C

16 FRCC.PC.049.A3.02

Manage o-cycle migration

O-cycle refrigerant migration happens:

• when the compressor is located at the coldest
part of the installation, and refrigerant vapour
then condenses in the compressor, or

Requirement

The amount of liquid refrigerant in the
compressors must not exceed the charge limit.

System evaluation

Non split Split Below charge limitAbove charge limit

X X Optional Optional Mandatory Optional

X X Mandatory Mandatory Mandatory Recommended

X - - Mandatory Mandatory Mandatory Recommended

*Surface sump heater
The surface sump heaters are designed to
protect the compressor against o-cycle
refrigerant migration.
Additional heater power or thermal insulation
is needed in case the ambient temperature falls
below -5°C and the wind speed is above 5 m/sec.
The heater must be turned on whenever all the
compressors are o.
Surface sump heater accessories are available
from Danfoss (see the “Accessories” section).

Surface sump

heater*

• directly in the liquid phase as the result of
gravity. When the compressor starts running
again, the refrigerant diluted in the oil generates
poor lubrication conditions. In extreme
situations, this leads to liquid slugging that can
damage compressor parts.

Non-return valve

Liquid line

solenoid valve**

Pump-down

cycle***

**Liquid line solenoid valve (LLSV)
An LLSV is used to isolate the liquid charge
on the condenser side, thereby preventing
refrigerant being transferred to the compressor
during o-cycles. The electronic expansion valve
that closes automatically including in power
shut down situation can replace the LLSV. The
quantity of refrigerant on the low-pressure side
of the system can be further reduced by using a
pump-down cycle in association with the LLSV.

***Pump-down cycle
By decreasing pressure in the sump, pump down:

• evacuates refrigerant from the oil

• sets the sump saturating pressure much lower
than the ambient temperature, and as a result,
refrigerant condensation is avoided in the
compressor.
Pump-down switch setting must be set higher
than 2.3 bar(g).

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Refrigerant charge limit
table

For more details on pump-down cycle see the
section “Control logic”.

Compressor models Refrigerant charge limit (kg)

VZH088 + SH090 / VZH088 + SH120 8.0

VZH117 + SH140, VZH117 + SH161, VZH117 + SH184 10.0

VZH170 + SH184, VZH170 + SH180, VZH170 + SH240,
VZH170 + SH295

15.0

17FRCC.PC.049.A3.02

Manage oil in the circuit

Oil management system
for hybrid manifolding

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

The oil management system architecture for
hybrid manifolding is described below.

An oil equalization tube between the variable
speed compressor and the xed speed
compressor is used to maintain the oil balance.

OEM main controller Drive

ModBus

FS

An oil level sensor need to be installed on the
variable speed compressor. The oil level sensor
monitors the compressor oil level and send oil
level signal to OEM main controller. When oil
level is below the minimal, OEM controller enter
in oil management mode to recover a proper
oil level in compressor. If oil level cannot be
recovered, controller stop the system.

VS

Oil management logic

Power supply

Oil equalization tube

In order to maintain the proper oil level in the
compressors, an oil management control logic
needs be implemented in the OEM controller.

The oil management control logic must include
three steps.

1. In the case of low oil level detection, an oil
balance mode (Variable speed on, Fixed speed
o) is activated to recover oil from xed speed
to variable speed.

Optical oil
level sensor

2. If oil level cannot be recovered in VS
compressor, controller go to Oil boost Mode
(Variable speed on, Fix Speed on) in order to
recover oil trapped in system.

3. If the oil level is still below the limit after a full
oil balance action and oil boost action have
been completed, the controller must enter in
protection mode, and stop the system in alarm.

For more detailed oil management logic, please
refer to “Oil management logic” in the annex.

18 FRCC.PC.049.A3.02

Manage oil in the circuit

Requirement

Fixed speed compressor: The oil level must

be visible or full in the sight glass when the
compressor is running and when all the
compressors in the circuit are stopped.

Variable speed compressor: This compressor is
equipped with an oil level switch located at the
minimum acceptable level. If the oil level drops
below this limit, the controller must follow the oil
logic (See “Oil management logic” in the annex).

R

Fixed speed compressor oil returned status
need be monitored in qualication test by
normal OSG on FS compressor or additional oil
level switch placed on FS OSG, the OEM should
make sure enough oil in FS compressor by test on
their own unit.

System evaluation

Basic unit

Single exchanger

as evaporator and

condenser

X - - X Optional Pass tests 1 & 2

- - - - - X Mandatory Pass tests 1, 2 & 3

Advance unit

Multiple exchangers as

evaporator or condenser

(heat-recovery, exchanger,

four-pipe chiller…)

X - - X Recommended Pass tests 1 & 2

Split

Non-reversible

Reversible

Non-split

Oil separator

Test, criteria and solutions

Tes t n o. Purpose Test condition Pass criteria Solutions

Variable speed On at minimum
speed / Fixed speed O
Running condition corresponds to
lowest foreseeable evaporation,
and highest foreseeable
condensation on the system

Running for 6 hours

For a reversible system, perform
the test in both heating and cooling

Oil return

1

2

3

test under
minimum mass
ow

Check oil
management
control logic is
working

Oil return in
split system

modes. If it is an advanced unit, test
in all possible congurations

Variable speed On at minimum
speed / Fixed speed On
Running condition corresponding
to lowest foreseeable evaporation,
and highest foreseeable
condensation on the system

Running for 6 hours

For a reversible system, perform
the test in both heating and cooling
modes. If it is an advanced unit, test
in all possible congurations

Variable speed On at 50 rps for
VZH088-117 or 40 rps for VZH170 /
Fixed speed On

Running conditions corresponding
to the lowest foreseeable
evaporation, and the highest
foreseeable condensation on the
system.

Running for 6 hours

For a reversible system, perform
the test in both heating and cooling
modes. If it is an advanced unit, test
in all possible congurations

Since each installation is unique,
tests 1 and 2 cannot fully validate
the oil return

The oil level must be checked and
adjusted at commissioning

Variable speed: No lack of oil alarm

No more than two oil boost cycles
per hour

Variable speed: No lack of oil alarm
Fixed speed: Oil visible in sight glass

No more than two oil balance cycles
per hour

Fixed speed: Oil visible in sight glass

Fix speed: Oil visible in sight glass

No more than two oil balance cycles
per hour

Look for potential oil trap
Increase oil boost duration
Top up with oil, generally 4% of the
total system refrigerant charge (in
weight)

Oil separator can be added

Look for potential oil trap
Increase oil boost duration
Top up with oil, generally 4% of the
total system refrigerant charge (in
weight). If more than 4% is used,
look for a potential oil trap in the
system

Oil separator can be added

The oil separator is mandatory
Pay special attention to “Piping
design”
Top-up with oil, generally 4% of the
total system refrigerant charge (in
weight). If more than 4% is used,
look for a potential oil trap in the
system

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Tes t

19FRCC.PC.049.A3.02

Control logic

Safety control logic
requirements

Safeties

HP switch

LP safety switch

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Electronic module (only for

SH180-240 -295)

Cycle rate limit
requirements

Defrost logic
recommendations

Tripping conditions Re-start conditions

Value Time Value Time

See the pressure settings

table in the “Manage

operating envelope section”

Contact M1-M2 opened

Immediate, no delay

No by-pass

Danfoss requires a minimum compressor running
time of 3 minutes to ensure proper oil return and
sucient motor cooling.
Additionally, the compressor service life is based
on max. 12 starts per hour.

In reversible systems, the defrost logic can be
worked out to limit the eects of liquid ood
back by:

1. Running at full load during defrost to share the
liquid refrigerant between all the compressors.

The following defrost logic combines both
advantages:

Manual reset

Conditions back to normal

Switch closed again

Max. 5 auto resets during a

12-hour period, then manual

reset

Max. 5 auto resets during a

12-hour period, then manual

reset

Therefore, to meet these two requirements,
a three-minute (180 sec.) time-out is
recommended.

2. Transferring the liquid refrigerant from one
exchanger to the other thanks to pressures.

Variable speed 1

Fixed speed 2

4WV

EXV

ON

ON

Heating

100%

Defrost start. Stop all compressors

4 Way Valve (4WV) stays in heating mode.

EXV opens to transfer liquid from outdoor

to indoor exchanger thanks to pressure

dierence

* EXV opening degree and time have to be set to keep a minimum pressure for 4 way valve moving.

When the pressures are almost bal-

anced*, 4WV changes to cooling mode

Restart variable speed and xed speed

Defrost

Defrost end. Stop all compressors

4 WV stays in cooling mode.

EXV opens to transfer liquid from

indoor to outdoor exchanger thanks

to pressure dierence

When pressures are almost balanced*,

Restart variable speed and xed speed

change 4WV to heating mode.

20 FRCC.PC.049.A3.02

Control logic

Pump-down logic
recommendations

Pump down is initiated prior to shutting
down the last compressor on the circuit by
de-energizing a liquid line solenoid valve or
closing electronic expansion valve. When suction
pressure reaches the cut-out pressure, the
compressor is stopped.

Two types of pump-down exist:

• One-shot pump down (preferred): When the

last compressor in the circuit stops, the suction
presssure is falls by 1.5 bar below the nominal
evaporating pressure with a minimum of 2,3
bar(g). Even if the suction pressure increases
again, the compressor will not restart.

• Continuous pump-down: Compressor restarts

automatically when the suction pressure
increases.

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

21FRCC.PC.049.A3.02

Assembly line procedure

The installation and service procedure for a
parallel system are similar to basic single-system
installations. The selection of additional system
components for parallel installations follows

Handling Danfoss Commercial Compressors recommends

using the lift and handling devices as shown on
the right, and that the following procedure be
used to prevent damage:

• There are two lifting rings on each compressor.

GENERAL INFORMATIONPRODUCT INFORMATIONORDERING INFORMATION SYSTEM DESIGN

Use all four rings.

• Maximum loads authorized per sling and for the
hoist hook must not be lower than the weight
of the assembly.

• If the tandem unit is already installed as a
complete installation, it must never be lifted
using the lifting rings on the compressors.

the basic system common rules. Please refer
to the application guidelines for Danfoss VZH
scroll compressors (FRCC.PC.023) for detailed
installation and service procedures.

22 FRCC.PC.049.A3.02

Ordering information

To build a complete tandem installation,
the customer must order two must order 2

Compressor ordering
codes

Danfoss VZH and SH scroll compressors can be
ordered in either industrial packs or in single
packs. Please refer to the single compressor

Accessory ordering codes

The suction separator and tandem kit can
be ordered using the code numbers listed in
the table below. The suction separator and

Tandem model

VZH178 VZH088 SH090 Left/Right

VZH208 VZH088 SH120 Left/Right

VZH257 V ZH117 SH140 Left/Right

VZH278 V ZH117 SH161 Left/Right

VZH301 V ZH117 SH184 Left/Right

VZH350 VZH170 SH180 Left/Right

VZH354 VZH170 SH184

VZ H410 VZH170 SH240 Left/Right

VZH465 VZH170 SH295 Left/Right

Variable speed

compressor

Fixed speed
compressor

direction

Suction

Left

Right

Suction separator Tandem accessory kit

Hz (FS

compressor)

50 Hz 120Z0676 1

60 Hz 120Z0675 1

50 Hz 120Z 0664 1

60 Hz 120Z0 658 1

50 Hz 120Z0666 1

60 Hz 12 0Z0665 1

50 Hz 12 0Z0665 1

60 Hz 120Z0674 1

50 Hz 120Z0 656 1

60 Hz 120Z0 656 1

50 Hz 120Z0 657 1

60 Hz 120Z0 657 1

50 Hz

60 Hz 120Z0 655 1

50 Hz 12 0Z0687 1

60 Hz 120Z0 687 1

50 Hz 120Z0 657 1

60 Hz 120Z0 657 1

50 Hz 120Z0 655 1

60 Hz 120Z0 655 1

Code Pack size

120Z0683

compressors, one suction separator and one
tandem accessory kit.

application guideline for compressor ordering
information (FRCC.PC.023 for VZH, FRCC.PC.007
for SH).

the tandem kit selection should be based on
compressor model, frequency of xed speed
compressor and oil level switch voltage.

Voltage of oil

level switch

24V 120Z0653 1

230V 120 Z06 54 1

24V 120Z0653 1

230V 120 Z06 54 1

24V 120Z0651 1

230V 120Z0652 1

24V 120Z0651 1

230V 120Z0652 1

24V 120Z0653 1

230V 120 Z06 54 1

24V 120Z0653 1

230V 120 Z06 54 1

24V 120Z0653 1

230V 120 Z06 54 1

24V 120Z0653 1

230V 120 Z06 54 1

24V 120Z0651 1

230V 120Z0652 1

24V 120Z0651 1

230V 120Z0652 1

24V 120 Z06 49 1

230V 120 Z0650 1

24V 120 Z06 49 1

230V 120 Z0650 1

1

24V 120Z0682 1

230V 120Z06 81 1

24V 120Z0682 1

230V 120Z06 81 1

24V 120Z0682 1

230V 120Z06 81 1

24V 120Z0682 1

230V 120Z06 81 1

24V 120 Z06 49 1

230V 120 Z0650 1

24V 120 Z06 49 1

230V 120 Z0650 1

24V 120 Z06 49 1

230V 120 Z0650 1

24V 120 Z06 49 1

230V 120 Z0650 1

Code Pack size

GENERAL INFORMATIONPRODUCT INFORMATIONSYSTEM DESIGNORDERING INFORMATION

23FRCC.PC.049.A3.02

Accessories

Suction separator

Code no. Description Application Packaging Pack size

120Z0 676 Hybrid manifold suction separator VZH178 (50Hz) - right/left suction Single pack 1

120Z0 675 Hybrid manifold suction separator VZH178 (60Hz) - right/left suction Single pack 1

120Z0 664 Hybrid manifold suction separator VZH208 (50Hz) - right/left suction Single pack 1

120Z0 658 Hybrid manifold suction separator VZH208 (60Hz) - right/left suction Single pack 1

120Z0666 Hybrid manifold suction separator VZH257 (50Hz) - right/left suction Single pack 1

GENERAL INFORMATIONPRODUCT INFORMATIONSYSTEM DESIGNORDERING INFORMATION

120Z0 665 Hybrid manifold suction separator

120Z0 674 Hybrid manifold suction separator VZH278 (60Hz) - right/left suction Single pack 1

120Z0 656 Hybrid manifold suction separator VZH301 (50/60Hz) - right/left suction Single pack 1

120Z0 657 Hybrid manifold suction separator

120Z0 655 Hybrid manifold suction separator

120Z0683 Hybrid manifold suction separator VZH354(50Hz) - left suction Single pack 1

120Z0 687 Hybrid manifold suction separator VZH354(50/60Hz) - right suction Single pack 1

VZH257 (60Hz) - right/left suction
VZH278 (50Hz) - right/left suction

VZH350 (50/60Hz) - right/left suction,
VZH410 (50/60Hz) - right/left suction

VZH465 (50/60Hz) - right/left suction,

VZH354 (60Hz) - left suction

Single pack 1

Single pack 1

Single pack 1

Tandem accessory kit

Code no. Description Application Packaging Pack size

120Z0 653 Oil level sensor 24V AC/DC, sleeves, gaskets

120Z0 654 Oil level sensor 230V AC, sleeves, gaskets

120Z0 651 Oil level sensor 24V AC/DC, sleeves, gaskets

120Z0 652 Oil level sensor 230V AC/DC, sleeves, gaskets

120Z0 649

120Z0 650

120Z0 681

120Z0682

Oil level sensor 24V AC/DC, sleeves, gaskets, grommets,
washers, bolts

Oil level sensor 230V AC, sleeves, gaskets, grommets,
washers, blots

Oil level sensor 230V AC, sleeves, gaskets, grommets,
washers, blots

Oil level sensor 24V AC, sleeves, gaskets, grommets, washers,
blots

VZH178-257-278

with 24V oil level sensor

VZH178-257-278

with 230V oil level sensor

VZH208-301

with 24V oil level sensor

VZH208-301

with 230V oil level sensor

VZH350-410-465

with 24V oil level sensor

VZH350-410-465

with 230V oil level sensor

VZH354

with 230V oil level sensor

VZH354

with 24V oil level sensor

Single pack 1

Single pack 1

Single pack 1

Single pack 1

Single pack 1

Single pack 1

Single pack 1

Single pack 1

Oil level sensor

Code no. Description Application Packaging Pack size

120Z0 561 Oil level sensor 24V AC/DC VZH088-117-170 manifolding version Single pack 1

120Z0 562 Oil level sensor 230V AC VZH088-117-170 manifolding version Single pack 1

24 FRCC.PC.049.A3.02

Accessories

Surface Sump Heater

Code no. Description Application Packaging Pack size

120Z0388 Surface sump heater, 80W, 24V, CE, UL

120Z0389 Surface sump heater, 80W, 230V, CE, UL Multipack 8

120Z0390 Surface sump heater, 80W, 400V, CE, UL Multipack 8

120Z0391 Surface sump heater, 80W, 460V,CE, UL Multipack 8

120Z0 402 Surface sump heater, 80W, 575V, CE, UL Multipack 8

120Z0360 Surface sump heater + bottom insulation, 56 W, 24 V, CE, UL

120Z0376 Surface sump heater + bottom insulation, 56 W, 230 V, CE, UL Multipack 6

120Z0377 Surface sump heater + bottom insulation, 56 W, 400 V, CE, UL Multipack 6

120Z0378 Surface sump heater + bottom insulation, 56 W, 460 V, CE, UL Multipack 6

120Z0379 Surface sump heater + bottom insulation, 56 W, 575 V, CE, UL Multipack 6

VZH088-117

SH090 -105-120-140 -161-184

VZH170

SH180

Multipack 8

Multipack 6

GENERAL INFORMATIONPRODUCT INFORMATIONSYSTEM DESIGNORDERING INFORMATION

25FRCC.PC.049.A3.02

Annex

Oil Management logic

1. Oil management for
hybrid manifolding
system

An oil level sensor needs to be installed on
the variable speed compressor. The oil level is
permanently monitored by OEM main controller.
When oil level is below the minimal, OEM

OEM main controller Drive

ModBus

FS

controller enters in oil management mode to
recover a proper oil level in compressor. If oil level
cannot be recovered, controller stops the system.

VS

2. Oil management
description

2.1 Basic rules

Power supply

Oil equalization tube

Oil management system for hybrid manifolding

This specication describes the control logic to
implement in OEM controller. This control logic
must be implemented and thoroughly tested by
OEM.

The variable speed compressor (VS) is primary
and the xed speed compressor (FS) is Secondary.
FS must not run alone.

Optical oil
level sensor

As oil balancing logic needs to start / stop
compressor as well as increase / decrease speed,
make sure expansion device is fast enough to
maintain liquid ood back within acceptable
limit during those transients (Manage super heat
chapter).

26 FRCC.PC.049.A2.02

Annex

2S

2.2 Oil management modes

The oil management control logic must include
3 steps.

Less than every

20min (TD2*)

Max 45 sec

(TD1*)

Fix speed ON

Oil

balance

Fix speed OFF

Partial Oil

boos (VS only)

Step 1Step

Normal

operation

Low oil level

>5 sec

Low oil

level

Step 1 (Oil balance or partial oil boost)

In case of low oil level detection by Oil level
sensor on VS, there is 2 possible actions
according to x speed state:

• Fix speed is ON: Oil can be trapped in x speed
compressor due to pressure unbalance. Oil
balance mode is activated. FS is stopped and
VS speed is increased; pressure in VS become
lower than FS oil is coming back through oil
equalization line.

• Fix speed is OFF: Oil is trapped in the system.
Partial oil boost is activated. VS speed is
increased to slightly increase refrigerant velocity
in the system and recover oil, FS remain OFF

Less than every

45min (TD4*)

Max 5min

(TD3*)

Oil level

not

recovered

Oil

Boost

(FS + VS)

Oil level

not

recovered

than TD2 after last step 1, switch immediately to
step 2.

Step 2 (Full oil boost)

If oil level cannot be recovered within dened
time, oil is trapped in the system. Full oil boost
is activated. (VS speed is increased and x starts
(if not already ON). It considerably increases
refrigerant velocity in the system and recovers oil.

TD3 is the maximum time to complete step 2. If
oil is not recovered within TD3 switch to step 3. If
oil is recovered within TD3 come back to normal
operation. TD4 is the minimum interval between
two step 2. In case of low oil level detection
within a time <TD4, switch to step 3.

Protection

tep 3

TD1 is the maximum time to complete
Step 1: If oil is not recovered within TD1, switch to
Step 2: If oil is recovered within TD1 come back to
normal operation. TD2 is the minimum interval
between two step 1. If step 1 is requested in less

Step 3 (Protection)

If oil is still lower than limit after completed step
1 & 2, or if oil level drop within a time <TD4,
controller must enter in protection mode, and
stop the system in alarm.

Note: TD time is adjustable. Please refer to “Parameter and variable table” in page 31.

27FRCC.PC.049.A2.02

Annex

2.3 Steps description

2.3.1 Oil balance Function description

Balance oil from FS compressor to VS Compressor.

Enter condition

Low oil level in VS compressor detected by oil
level sensor.

AND

FS compressor is ON

AND

t2>TD2, Interval between two Oil balance / Oil
boost is > TD2

Cancel condition

High oil level in VS compressor detected by oil
level sensor.
OR
t1>TD1, Oil balance duration exceed TD1

Control sequence

1. At the initial state, VS and FS compressor are
ON.

2. Low oil level detected in VS compressor. Reset
and Start t1.

3. FS compressor must stop. VS compressor speed
must increase to Fboost.

4. When high oil level detected in VS compressor.

• VS compressor speed must be decreased to

minimal speed Fmin.

• Reset and Start t2

• Reset t1

5 When VS compressor speed reaches FStart, FS
compressor must restart.

Max TD1

Oil level signal

VS speed

FS speed

t1

Oil lack

2

Fboost

1

3

Oil balance

from FS to VS

compressor

4

t2

FstartFstart

5

28 FRCC.PC.049.A2.02

Annex

2.3.2 Partial oil boost Function description

Return oil trapped in the system to compressors
by increasing refrigerant mass-ow in the system.

Enter condition

Low oil level in VS compressor detected by oil
level sensor.

AND

FS compressor is OFF

AND

t2>TD2, Interval between two Oil balance / Oil
boost is > TD2

Cancel condition

High oil level in VS compressor detected by oil
level sensor.
OR
t1>TD1,Partial oil Boost duration exceed TD1

Oil level signal

VS speed

Control sequence

1 At the initial state, VS compressor is ON and FS

compressor is OFF.

2 Low oil level detected in VS compressor. Reset

and start t1
3 VS compressor speed must increase to Fboost.
4 When high oil level detected in VS compressor

• VS compressor speed must be decreased to the

initial speed (Fstart)

• Reset and start t2

• Reset t1

Max TD1

t1

Oil lack

2

1

3

Fboost

4

t2

FS speed

29FRCC.PC.049.A2.02

Annex

2.3.3 Oil boost Function description

Return oil trapped in the system to compressors
by increasing refrigerant mass-ow in the system.

Enter condition

Low oil level in VS compressor detected by oil
level sensor.

AND

(t1>TD1, Oil balance / boost duration t1 > TD1 OR
t2<TD2, Interval between two Oil balance / Oil
boost is < TD2)

Cancel condition

High oil level in VS compressor detected by oil
level sensor.
OR
t1>TD3, Oil balance / boost duration exceeds
Maximum Oil boost duration

Control sequence

1. At initial state, oil level is low .Partial oil boost
/Oil balance was not successful or was aborted
because minim interval criteria. VS compressor is
at FStart and FS compressor is either ON or OFF.

2. VS compressor speed must increase to Fboost,
FS compressor must start if not already ON
Reset and start t1

3. When High oil level detected in VS compressor.

• VS compressor speed must be decreased to the
initial speed (Fstart)

• FS compressor to initial state.

• Reset and start t2

• Reset and start t3

• Reset t1

4. When VS compressor speed reaches FStart, FS

compressor must restart (if was ON before)

Max TD3

t1

2

Oil lack

t2

VS comp

FS comp

1

Fboost

3

FstartFstart

30 FRCC.PC.049.A2.02

Annex

24VDC MODEL

24VAC MODEL

24VDC MODEL

2.3.4 Protection

Function description

Stop compressors to prevent short of oil running.

Enter condition

Low oil level in VS compressor detected by oil
level sensor.

AND

(t1>TD3, Oil balance / boost duration exceeds

Cancel condition

Manual Reset

Control sequence

Stop FS and VS compressor
Reset t1
Reset t2

Reset t3
TD3 OR t3<TD4, Interval between two Oil boost
is < TD4)

2.4 Parameter and variable
table

Name Te xt Attribute Range Default Unit

Fboost Boost action frequency parameter 25~100 70 Hz

TD1 Maximum oil balance / Partial oil boost duration parameter 10~240 30 second

TD2 Interval minimum between two oil balance / Partial oil boost parameter 10~60 20 minutes

TD3 Maximum boost duration parameter 5~12 5 minutes

TD4 Interval minimum between two oil boost parameter 45~120 45 minutes

t1 Oil balance/ Partial oil boost timer Variable second

t2 Interval between two oil balance / Partial oil boost Variable minutes

t3 Interval between two oil boost Variable minutes

2.5 Sensor Wiring diagram

230VAC MODEL

24VAC MODEL

An TEKLAB LC-XN optical-electrical level sensor
is xed on the inverter compressor. The oil
level sensor monitors the compressor oil level
and sends oil level signal to an external relay
(provided by OEM ). Regarding this oil level
signal, a 5±2 seconds delay is recommended to

owing through load or coil of external relay.
For relay, output is open.

- Enough oil: Circuit between 2 and 3 will be
closed internally, there will be current owing
through load or coil of external relay. For relay,
output is closed

24VDC MODEL

be used to consider the oil level uctuation which
may trigger false alarms.

For customers who needs UL certicates, please
order 24V AC/DC sensor.

- Lack of oil: Circuit between 2 and 3 will be
opened internally, there will be no current

31FRCC.PC.049.A2.02

Updates

Previous Version Current Version

• Page 10: Suction separator code

• Page 17: Refrigerant charge limit table

• Page 23: Suction separator code

• Page 24: Suction separator accessories

• Page 10: Updated SH184 Left suction 60Hz in
Suction separator code

• Page 17: Updated Refrigerant charge limit table

• Page 23: Updated VZH354 Left suction 60Hz in
Suction separator code

• Page 24: Updated Suction separator accessories

32 FRCC.PC.049.A3.02

Danfoss Commercial Compressors

Danfoss Inverter Scrolls

is a worldwide manufacturer of compressors and condensing units for refrigeration and HVAC applications. With a wide range
of high quality and innovative products we help your company to find the best possible energy efficient solution that respects
the environment and reduces total life cycle costs.

We have 40 years of experience within the development of hermetic compressors which has brought us amongst the global
leaders in our business, and positioned us as distinct variable speed technology specialists. Today we operate from engineering
and manufacturing facilities spanning across three continents.

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Our products can be found in a variety of applications such as rooftops, chillers, residential air conditioners,
heatpumps, coldrooms, supermarkets, milk tank cooling and industrial cooling processes.

http://cc.danfoss.com

Danfoss Commercial Compressors, BP 331, 01603 Trévoux Cedex, France | [phone]

FRCC.PC.049.A3.02 © Danfoss | DCS (CC) | 2017.11