Daikin EWWD170~600G-SS, EWWD190~650G-XS, EWLD160~550G-SS Operation manuals
Installation, Operation and Maintenance Manual
D–EIMWC00208-16EN
Water-cooled screw chillers
EWWD170~600G-SS
EWWD190~650G-XS
EWLD160~550G-SS
50Hz – Refrigerant: R-134a
Original Instructions
IMPORTANT
This Manual is a technical aid and does not represent a binding offer for Daikin.
Daikin has drawn up this Manual to the best of its knowledge. The content cannot be held as explicitly or implicitly
guaranteed as complete, precise or reliable.
All data and specifications contained herein may be modified without notice. The data communicated at the moment
of the order shall hold firm.
Daikin shall assume no liability whatsoever for any direct or indirect damage, in the widest sense of the term,
ensuing from or connected with the use and/or interpretation of this Manual.
The entire content is protected by Daikin copyright.
WARNING
Before starting the installation of the unit, please read this manual carefully. Starting up the unit is absolutely
forbidden if all instructions contained in this manual are not clear.
1 – Lifting instructions
6 – Hazardous Voltage warning
2 – Unit nameplate data
7 – Cable tightening warning
3 – Emergency stop
8 – Electrical hazard symbol
4 – Gas type
9 – Water circuit filling warning
5 – Manufacturer’s logo
10 - Non flammable gas symbol
Key to symbols
Important note: failure to respect the instruction can damage the unit or compromise operation
Note regarding safety in general or respect of laws and regulations
Note regarding electrical safety
Description of the labels applied to the electrical panel
Single compressor unit
Label Identification
D-EIMWC00208-16EN - 2/48
1 – Lifting instructions
6 – Non flammable gas symbol
2 – Unit nameplate data
7 – Manufacturer’s logo
3 – Hazardous Voltage warning
8 – Emergency stop
4 – Cable tightening warning
9 – Water circuit filling warning
5 – Gas type
10 - Electrical hazard symbol
Label Identification
Two compressors unit
D-EIMWC00208-16EN - 3/48
Contents
General information ............................................................................................................................................................ 6
Warnings for the operator ................................................................................................................................................... 6
Assistance .......................................................................................................................................................................... 6
Spare parts ......................................................................................................................................................................... 6
Receiving the machine ....................................................................................................................................................... 6
Checks ................................................................................................................................................................................ 6
Purpose of this manual ....................................................................................................................................................... 7
Important information on the refrigerant used .................................................................................................................... 7
Mechanical Installation ....................................................................................................................................................... 8
Shipping .............................................................................................................................................................................. 8
Responsibility ..................................................................................................................................................................... 8
Safety.................................................................................................................................................................................. 8
Moving and lifting................................................................................................................................................................ 8
Positioning and assembly ................................................................................................................................................... 9
Minimum space requirements .......................................................................................................................................... 10
Ventilation ................................................................................................................................................................ ......... 10
Sound protection .............................................................................................................................................................. 10
Water piping...................................................................................................................................................................... 10
Water treatment ................................................................................................................................................................ 11
Evaporator and exchangers antifreeze protection ........................................................................................................... 12
Installing the flow switch ................................................................................................................................................... 12
Guidelines for remote condenser application ................................................................................................................ 13
Refrigerant piping design.................................................................................................................................................. 13
Electrical Installation ........................................................................................................................................................ 17
General specifications ...................................................................................................................................................... 17
Electrical components ...................................................................................................................................................... 18
Electrical wiring ................................................................................................................................................................. 18
Electrical heaters .............................................................................................................................................................. 18
Water pump control .......................................................................................................................................................... 18
Unit On/Off remote control – Electrical wiring .................................................................................................................. 18
Double Setpoint – Electrical wiring ................................................................................................................................... 18
External water Setpoint reset – Electrical wiring (Optional) ............................................................................................. 18
Unit limitation Electrical wiring (Optional) ................................ ........................................................................................ 19
Operation............................................................................................................................................................................ 20
Operator’s responsibilities ................................................................................................................................................ 20
Description of the machine ............................................................................................................................................... 20
Description of the refrigeration cycle ................................................................................................................................ 20
Description of the refrigeration cycle with partial heat recovery ....................................................................................... 24
Controlling the partial recovery circuit and installation recommendations ....................................................................... 24
Compression process ....................................................................................................................................................... 25
Prestartup checks ............................................................................................................................................................. 29
General ................................................................................................ ............................................................................. 29
Units with external water pump ........................................................................................................................................ 30
Electrical power supply ..................................................................................................................................................... 30
Unbalance in power supply voltage.................................................................................................................................. 30
Electrical heaters power supply ........................................................................................................................................ 30
Emergency Stop ............................................................................................................................................................... 30
Startup procedure ............................................................................................................................................................. 31
Turning on the machine .................................................................................................................................................... 31
Seasonal shutdown .......................................................................................................................................................... 32
Starting up after seasonal shutdown ................................................................ ................................................................ 32
System maintenance......................................................................................................................................................... 33
General ................................................................................................ ............................................................................. 33
Compressor maintenance ................................................................................................................................................ 33
Lubrication ........................................................................................................................................................................ 33
Routine maintenance................................................................................................................................ ........................ 34
Replacement of filter dryer ............................................................................................................................................... 35
Procedure to replace the filter dryer cartridge .................................................................................................................. 35
Replacement of the oil filter ................................................................ .............................................................................. 36
Refrigerant charge ............................................................................................................................................................ 37
Procedure to replenish refrigerant .................................................................................................................................... 37
Standard Checks ............................................................................................................................................................... 38
Temperature and pressure sensors ................................................................................................................................. 38
Test sheet ........................................................................................................................................................................... 39
Water side measurements................................................................................................................................................ 39
Refrigerant side measurements ....................................................................................................................................... 39
D-EIMWC00208-16EN - 4/48
Electrical measurements .................................................................................................................................................. 39
Service and limited warranty............................................................................................................................................ 40
Obligatory routine checks and starting up apparatuses under pressure ................................................................... 41
Important information regarding the refrigerant used .................................................................................................. 41
Table contents
Table 1 - Acceptable water quality limits ................................ ................................................................ .. 11
Table 2 - Equivalent Lengths (in meters) ................................ ................................ .................................. 15
Table 3 - Liquid line sizes .......................................................................................................................... 16
Table 4 - Discharge line sizes.................................................................................................................... 16
Table 5 - Typical operating conditions with compressors at 100% ........................................................ 31
Table 6 - Routine maintenance programme ............................................................................................. 34
Figures contents
Fig. 1 - Lifting the unit .................................................................................................................................. 9
Fig. 2 - Minimum clearance requirements for machine maintenance ..................................................... 10
Fig. 3 - Water piping connections for evaporator .................................................................................... 11
Fig. 4 - Water piping connection for heat recovery exchangers ............................................................. 11
Fig. 5 - Adjusting the safety flow switch................................................................................................ ... 12
Fig. 6 - Condenser Located with No Elevation Difference ....................................................................... 13
Fig. 7 - Condenser Located above Chiller Unit ........................................................................................ 14
Fig. 8 - Condenser Located below Chiller Unit......................................................................................... 14
Fig. 9 - User connection to the interface terminal board ................................ ................................ ......... 19
Fig. 10 - Refrigeration cycle EWWD G-SS, EWWD G-XS ......................................................................... 21
Fig. 11 - Refrigeration cycle EWWD G-SS, EWWD G-XS Partial Heat recovery .................................... 22
Fig. 12 - Refrigeration cycle EWLD G-SS.................................................................................................. 23
Fig. 13 - Picture of Fr3200 compressor .................................................................................................... 25
Fig. 14 - Compression process ................................................................................................................. 26
Fig. 15 - Refrigeration capacity control mechanism of compressor Fr3200 .......................................... 27
Fig. 16 - Capacity control mechanism ...................................................................................................... 28
Fig. 17 - Installation of control devices for Fr 3200 compressor ............................................................ 34
D-EIMWC00208-16EN - 5/48
General information
ATTENTION
The units described in the present manual represent a valuable investment. Maximum care should be taken to
ensure correct installation and appropriate working conditions of the units.
Correct maintenance of the unit is indispensable for its safety and reliability. Manufacturer’s service centres are the
only having adequate technical skill for maintenance.
ATTENTION
This manual provides information about the features and procedures for the complete series.
All units are delivered from factory as complete sets which include wiring diagrams and dimensional drawings with
size, weight and features of each model.
WIRING DIAGRAMS AND DIMENSIONAL DRAWINGS MUST BE CONSIDERED ESSENTIAL DOCUMENTS OF
THIS MANUAL
In case of any discrepancy between this manual and the two aforesaid documents, please refer to the wiring diagram
and dimensional drawings.
IMPORTANT
The present Installation and Maintenance Manual is drawn up for information only and does not constitute an offer
binding upon Daikin.
Specifications are subject to change without prior notice. Refer to the data communicated at the time of the order as
per the “Documents Certified” such as “Dimensional Drawings”, “Wiring diagrams” and “Nameplate”. Daikin explicitly
rejects any liability for any direct or indirect damage, in the broadest sense, arising from or related to the use and/or
interpretation of this Installation and Maintenance Manual.
Safe use and maintenance of the unit, as explained in this Maintenance and Use Manual, is fundamental to prevent any
accidents occurring to operators during both operation and maintenance as well as during repair work.
Therefore, it is highly recommended that this document be read carefully, complied with and stored safely.
Warnings for the operator
READ THIS MAINTENANCE AND USE MANUAL BEFORE USING THE UNIT
THE OPERATOR MUST BE TRAINED AND INSTRUCTED ON HOW TO USE THE UNIT
THE OPERATOR MUST STRICTLY FOLLOW ALL INSTRUCTIONS, SAFETY REGULATIONS AND
LIMITATIONS REGARDING THE USE OF THE UNIT.
Assistance
Should additional maintenance be required, it is advisable to consult authorised staff before carrying out any repair work.
Spare parts
Spare parts to be used for maintenance of the unit must be original. Therefore, always consult the manufacturer.
Receiving the machine
The machine must be inspected for any possible damage immediately upon reaching its final place of installation. All
components described in the delivery note must be carefully inspected and checked; any damage must be reported to
the carrier. Before connecting the machine to earth, check that the model and power supply voltage shown on the
nameplate are correct. Responsibility for any damage after acceptance of the machine cannot be attributed to the
manufacturer.
Checks
To prevent the possibility of incomplete delivery (missing parts) or transportation damage, please perform the following
checks upon receipt of the machine:
D-EIMWC00208-16EN - 6/48
a) Before accepting the machine, please verify every single component in the consignment. Check for any
damage.
b) In the event that the machine has been damaged, do not remove the damaged material. A set of photographs
are helpful in ascertaining responsibility.
c) Immediately report the extent of the damage to the transportation company and request that they inspect the
machine.
d) Immediately report the extent of the damage to the manufacturer representative, so that arrangements can be
made for the required repairs. In no case must the damage be repaired before the machine has been inspected
by the representative of the transportation company.
Purpose of this manual
The purpose of this manual is to allow the installer and the qualified operator to carry out all required operations in order
to ensure proper installation and maintenance of the machine, without any risk to people, animals and/or objects.
This manual is an important supporting document for qualified personnel but it is not intended to replace such
personnel. All activities must be carried out in compliance with local laws and regulations.
Important information on the refrigerant used
This product contains fluorate gases which have a greenhouse effect and which are covered by the Kyoto protocol. Do
not release such gases into the atmosphere.
Type of refrigerant: R134A
GWP value
The quantity of refrigerant used is indicated on the identity plate with the name of the unit.
Routine inspections may be necessary pursuant to local and/or European laws, to check on possible refrigerant leakage.
For more detailed information, contact your local dealer.
(1)
= 1430
(1) GWP=Global warming potential
D-EIMWC00208-16EN - 7/48
Mechanical Installation
WARNING
Before carrying out any operation on the machine, please read this instruction and operating manual carefully.
Installation and maintenance must be carried out only by qualified personnel that is familiar with the provisions of law
and local regulations and has been trained properly or has experience with this type of equipment.
WARNING
Avoid installing the machine in a place that could be dangerous during maintenance operations, such as (but not
only) platforms without parapets or railings or areas not complying with the clearance requirements.
Shipping
The stability of the machine during shipping must be ensured. If the machine is shipped with a wooden crossplank on its
base, the crossplank must be removed only after the final destination has been reached.
Responsibility
The manufacturer declines all responsibility, present and future, for any damage to persons, animals or property caused
by negligence of operators failing to follow the installation and maintenance instructions in this manual.
All safety equipment must be regularly and periodically checked in accordance with this manual and with local laws and
regulations regarding safety and environment protection.
Safety
The machine must be firmly secured to the ground.
It is essential to observe the following instructions:
- The machine can only be lifted using the lifting points on the base of the machine itself. These are the only points that
can support the entire weight of the unit.
- Do not allow unauthorised and/or unqualified personnel to access the machine.
- It is forbidden to access the electrical components without having opened the machine's general disconnecting switch
and switched off the power supply.
- It is forbidden to access the electrical components without using an insulating platform. Do not access the electrical
components if water and/or moisture are present.
- All operations on the refrigerant circuit and on components under pressure must be carried out by qualified personnel
only.
- Replacement of a compressor or addition of lubricating oil must be carried out by qualified personnel only.
- Sharp edges can cause wounds. Avoid direct contact.
- Avoid introducing solid bodies into the water pipes while the machine is connected to the system.
- A mechanical filter must be installed on the water pipe connected to the heat exchanger inlet.
- The machine is supplied with safety valves, that are installed on both the high and the low pressure sides of the
refrigerant circuit.
In case of sudden stop of the unit, follow the instructions on the Control Panel Operating Manual which is part of the
on-board documentation delivered to the end user with this manual.
It is recommended to perform installation and maintenance with other people. In case of accidental injury or unease, it is
necessary to:
- keep calm
- press the alarm button if present in the installation site
- move the injured person in a warm place far from the unit and in rest position
- contact immediately emergency rescue personnel of the building or if the Health Emergency Service
- wait without leaving the injured person alone until the rescue operators come
- give all necessary information to the the rescue operators
Moving and lifting
Avoid bumping and/or jolting during unloading from the lorry and moving the machine. Do not push or pull the machine
from any part other than the base frame. Secure the machine inside the lorry to prevent it from moving and causing
damage to the panels and to the base frame. Do not allow any part of the machine to fall during transportation and/or
unloading, as this could cause serious damage.
All units of the series are supplied with four lifting points. Only these points may be used for lifting the unit, as shown in
figure 1.
D-EIMWC00208-16EN - 8/48
WARNING
Both the lifting ropes and the spacing bar and/or scales must be strong enough to support the machine safely.
Please check the unit’s weight on the machine’s nameplate.
The weights shown in the "Technical data" tables in the "General Information" chapter refer to standard units.
Some specific machines might have accessories that increase their overall weight (heat recovery, etc.)
WARNING
The machine must be lifted with the utmost attention and care. Avoid jolting when lifting and lift the machine very
slowly, keeping it perfectly level.
Fig. 1 - Lifting the unit
Positioning and assembly
All units are designed for installation indoors. The machine must be installed on a robust and perfectly level foundation;
should the machine be installed on balconies or roofs, it might be necessary to use weight distribution beams.
For installation on the ground, prepare a strong cement base that is at least 250 mm wider and longer than the machine.
Also, this base must be strong enough to support the weight of the machine as stated in the technical specifications.
If the machine is installed in places that are easily accessible to people and animals, it is advisable to install protection
gratings for the compressor section.
To ensure the best possible performance on the installation site, the following precautions and instructions must be
followed:
Make sure to provide a strong and solid foundation to reduce noise and vibration as much as possible.
The water in the system must be particularly clean and all traces of oil or rust must be removed. A mechanical water
filter must be installed on the machine’s inlet piping.
D-EIMWC00208-16EN - 9/48
Minimum space requirements
Every side of the machine must be accessible for all postinstallation maintenance activities. Figure 2 shows the minimum
space necessary.
Fig. 2 - Minimum clearance requirements for machine maintenance
Ventilation
The temperature of the room where the unit is placed should be always maintained between 0°C and 40°C.
Sound protection
When sound levels require special control, great care must be exercised to isolate the machine from its base by
appropriately applying antivibration elements (supplied as an option). Flexible joints must be installed on the water
connections, as well.
Water piping
Piping must be designed with the lowest number of elbows and the lowest number of vertical changes of direction. In this
way, installation costs are reduced considerably and system performance is improved.
The water system must have:
1. Antivibration mountings in order to reduce transmission of vibrations to the underlying structure.
2. Isolating valves to isolate the machine from the water system during service.
3. Manual or automatic air venting device at the system’s highest point; drain device at the system’s lowest point.
Neither the evaporator nor the heat recovery device must be positioned at the system’s highest point.
4. A suitable device that can maintain the water system under pressure (expansion tank, etc.)
5. Water temperature and pressure indicators on the machine to assist the operator during service and
maintenance.
6. A filter or device which can remove foreign particles from the water before it enters the pump (in order to
prevent cavitation, please consult the pump manufacturer for the recommended type of filter ). The use of a
filter prolongs the life of the pump and helps keep the water system in a better condition.
7. Another filter must be installed on the machine inlet water pipe, near the evaporator and heat recovery (if
installed). The filter prevents solid particles from entering the heat exchanger, as they could damage it or
reduce its heat exchanging capacity.
8. The heat recovery device must be emptied of water during the winter season, unless an ethylenic glycol mixture
in appropriate percentage is added to the water circuit.
9. If the machine is intended to replace of another, the entire water system must be emptied and cleaned before
the new unit is installed. Regular tests and proper chemical treatment of water are recommended before
starting up the new machine.
10. In the event that glycol is added to the water system as antifreeze protection, pay attention to the fact that
suction pressure will be lower, the machine’s performance will be lower and water pressure drops will be
greater. All machineprotection systems, such as antifreeze, and lowpressure protection will need to be
readjusted.
Before insulating water piping, check that there are no leaks.
D-EIMWC00208-16EN - 10/48
Install a mechanical filter on the inlet to each heat exchanger. Failure to install a mechanical filter allows solid
particles and/or welding slag to enter the exchanger. Installation of a filter with a mesh size not exceeding 0.5 mm in
diameter is advised.
The manufacturer cannot be held responsible for any damage to exchangers ensuing from the lack of a mechanical
filter.
PH (25°C)
6.88.0
Total hardness (mg CaCO3 / l)
200
Electricity conductivity S/cm (25°C)
800
Iron (mg Fe / l)
1.0
Chloride ion (mg Cl / l)
200
Sulphide ion (mg S
2
/ l)
Nessuno
Sulphate ion (mg SO
24
/ l)
200
Ammonium ion (mg NH
4
+
/ l)
1.0
Alkalinity (mg CaCO3 / l)
100
Silica (mg SiO2 / l)
50
Fig. 3 - Water piping connections for evaporator
Fig. 4 - Water piping connection for heat recovery exchangers
Water treatment
Before putting the machine into operation, clean the water circuit. Dirt, scaling, corrosion residue and other foreign
material can accumulate inside the heat exchanger and reduce its heat exchanging capacity. Pressure drops can
increase as well, thus reducing water flow. Proper water treatment therefore reduces the risk of corrosion, erosion,
scaling, etc. The most appropriate water treatment must be determined locally, according to the type of system and local
characteristics of the process water.
The manufacturer is not responsible for damage to or malfunctioning of equipment caused by failure to treat water or by
improperly treated water.
Table 1 - Acceptable water quality limits
D-EIMWC00208-16EN - 11/48
Evaporator and exchangers antifreeze protection
3” 83 mm
4” 107 mm
5” 134 mm
6” 162 mm
For 3” - 6” piping
Use paddle b = 29 mm
Adjusting the flow switch’s
trigger sensitivity
Two or more of below protection methods should be considered when designing the system as a whole:
1. Continuous water flow circulation inside piping and exchangers.
2. Addition of an appropriate amount of glycol inside the water circuit.
3. Additional heat insulation and heating of exposed piping.
4. Emptying and cleaning of the heat exchanger during the winter season.
It is the responsibility of the installer and/or local maintenance personnel to ensure that two or more of the described
antifreeze methods are used. Make sure that appropriate antifreeze protection is maintained at all times. Failure to follow
the instructions above could result in damage to some of the machine’s components. Damage caused by freezing is not
covered by the warranty.
Installing the flow switch
To ensure sufficient water flow through the evaporator, it is essential that a flow switch be installed on the water circuit.
The flow switch can be installed either on the inlet or outlet water piping. The purpose of the flow switch is to stop the
machine in the event of interrupted water flow, thus protecting the evaporator from freezing.
A flow switch specifically gauged for this purpose, with identification code 131035072, is available as an option.
This paddletype flow switch is suitable for heavyduty outdoor applications (IP67) for pipe diameters in the range of 1" to
6".
The flow switch is provided with a clean contact which must be electrically connected to the terminals of the terminal
board (check the machine’s wiring diagram for further information).
For further information regarding device installation and settings, please read the instruction leaflet in the device box.
Refrigerating circuit safety valves
Each system comes with safety valves that are installed on each circuit, both on the evaporator and on the condenser.
The purpose of the valves is to release the refrigerant inside the refrigerant circuit in the event of certain malfunctions.
D-EIMWC00208-16EN - 12/48
Fig. 5 - Adjusting the safety flow switch
Guidelines for remote condenser application
Design of remote condenser application, and, in particular, sizing of piping and piping path, is a responsibility of plant
designer. This paragraph is only focused to give suggestion to plant designer, this suggestions have to be weighted with
references to application peculiarities.
For remote condenser application, such as aircooled or evaporative condensers, the chillers are shipped with holding
Nitrogen charge. It is important that the unit be kept tightly closed until the remote condenser is installed and piped to the
unit.
Chillers are supplied with filter drier, moisture indicator and expansion valve factory mounted as standard.
It is the contractor’s responsibility to install the interconnection piping, leak test it and the entire system, evacuate the
system and supply the refrigerant charge.
All piping must be conformed to the applicable local and state codes.
Use refrigerant grade copper tubing only and isolate the refrigeration lines from building structures to prevent transfer of
vibration.
It is important that the discharge lines be looped at the condenser and trapped at the compressor to prevent refrigerant
and oil from draining into the compressors; looping the discharge line also provide greater flexibility.
Do not use a saw to remove end caps. This might allow copper chips to contaminate the system. Use a tube cutter or
heat to remove caps. When sweating copper joints it is important to flow dry nitrogen through the system prior to
charging with refrigerant. This prevents scale formation and the possible formation of an explosive mixture of HFC134a
and air. This will also prevent the formation of toxic phosgene gas, which occurs when HFC134a is exposed to open
flame.
Soft solders are not to be used. For coppertocopper joints use a phoscopper solder with 6% to 8% silver content. A high
silver content brazing rod must be used for coppertobrass or coppertosteel joints. Only use oxyacetylene brazing.
After the equipment is correctly installed, leak tested and evacuated, it can be charged with R134a refrigerant and
started under the supervision of Daikin authorized technician.
Charge will be added until the liquid line sight glass is clear, with no bubbles flowing into the expansion valve. Total
refrigerant charge will depend on the used remote condenser and volume of refrigerant piping
Refrigerant piping design
The system can be configured in any of the main arrangements as shown in Figures 6, 7 and 8. The configuration and its
associated elevation, along with the total distance between the chiller and the aircooled condenser are important factors
in determining the liquid line and discharge line sizes. This will also affect the field refrigerant charges. Consequently,
there are physical limits that must not be violated if the system is to operate as designed.
1. The total distance between the chiller and the aircooled condenser should not exceed 60 equivalent meters
2. Liquid line risers must not exceed 5 meters in height from the condenser liquid line connection.
3. Discharge line risers cannot exceed an elevation difference greater than 30 actual meters.
Fig. 6 Condenser Located with No Elevation Difference
D-EIMWC00208-16EN - 13/48
Fig. 7 Condenser Located above Chiller Unit
Fig. 8 Condenser Located below Chiller Unit
D-EIMWC00208-16EN - 14/48
Line Size
OD
(inches)
Angle
Valve
Short
Radius EL
Long
1/4
5.8
0.8
0.6
3/8
7.3
1.2
0.9
1/2
7.3
1.4
1.0
5/8
7.6
1.7
1.2
3/4
7.6
2.0
1.4
7/8
8.5
2.4
1.6
11/8
8.8
0.8
0.6
13/8
10.1
1.0
0.7
15/8
10.4
1.2
0.8
21/8
11.9
1.6
1.0
25/8
13.4
2.0
1.3
31/8
14.3
2.4
1.6
Determining Equivalent Line Length
To determine the appropriate size for field installed liquid and discharge lines, it is first necessary to establish the
equivalent length of pipe for each line. The equivalent length is the actual friction loss from the linear run of pipe plus the
added friction loss of elbows, valves, etc. Table 2 shows the equivalent length of pipe for various nonferrous valves and
fittings. Follow these steps when calculating line size:
1. Start with an initial approximation of equivalent length by assuming that the equivalent length of pipe is 1.5 times
the actual pipe length.
2. Refer to Tables 2 and 3 for a first approximation of line size.
3. Check the line size by calculating the actual equivalent length.
Note: When calculating the equivalent length, do not include piping of the chiller unit. Only field piping must be
considered.
Table 2 - Equivalent Lengths (in meters)
Liquid Line Sizing
In designing liquid lines it is important that the liquid reaches the expansion valve without flash gas, since this gas will
reduce the valve capacity. Because flashing gas can be caused by pressure drop in the line, the pressure losses due to
friction and changes in static head should be kept at minimum.
A check valve must be installed in the liquid line where the ambient temperature can drop below the equipment room
temperature to prevent liquid migration to the condenser and to maintain liquid refrigerant in the line for unit startup (if
thermostatic expansion valve is used, the check valve also help to keep liquid pressure high enough to keep the valve
closed with compressor off).
A relief valve should be installed between the check valve and the expansion avlve.
The liquid line diameter should be as small as possible while maintaining acceptable pressure drop. This is necessary to
minimize refrigerant charge. The total length between the chiller unit and the aircooled condenser must not exceed 60
equivalent meters.
Liquid line risers in the system will require an additional 11.5 kPa pressure drop per meter of vertical rise. When it is
necessary to have a liquid line riser, make the vertical run immediately after the condenser before any additional
restrictions. The liquid line risers must not exceed 3 meters in height from the condenser liquid line connection. The liquid
line does not have to be pitched.
Liquid lines are not typically insulated. However, if the lines are exposed to solar heat gain or temperatures exceeding
43°C, subcooling may be effected. In these situations, insulate the liquid lines.
Reference for liquid line sizing is shown in Table 3. It has to be used for reference only, for circuit working with
condensing temperature equal to 55°C and 5°C subcooling at the condenser outlet. Line dimensioning is responsibility of
plant designer, use ASHRAE Refrigeration Handbook or other suitable design guide.
D-EIMWC00208-16EN - 15/48
Loading...