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AE4-1372 R5
User Manual
15 pgs974.24 Kb0

Emerson AE4-1372 R5 User Manual

© 2019 Emerson Climate Technologies Inc.
1
TABLE OF CONTENTS
Safety Instructions ....................................................... 2
Instructions Pertaining to Risk of Electrical Shock,
INTRODUCTION ......................................................... 4
CO2 FOR LOW TEMPERATURE APPLICATIONS
SUB-CRITICAL DX SYSTEM ...................................... 4
ASSEMBLY LINE PROCEDURES ............................... 8
MAINTENANCE AND REPAIR .................................... 9
FIGURES
Figure 1 CO2 Low Temp. Subcritical DX System ...... 12
Figure 2 Specially designed rubber rommets Kit # 527-
0157-00 ...................................................................... 13
Figure 3 Oil Management Control OMC-CO2 ............ 13
Figure 4 Suction Side Pressure Relief Valve
Requirements ............................................................. 14
Figure 5 Three Phase Power Circuit .......................... 15
Figure 6 - ZO Compressor Operating Envelope ........ 15
Figure 7 Compressor Electrical Connection ............... 15
Revision Tracking R4
Pg. 2 New Pressure Safety Icon added Pg. 4 Caution tag added to superheat requirement. Pg. 4 Notes about oil recharging values added. Pg. 5 Model numbers chart moved to pag. 10 and ZOD34K3E and ZOD104KCE added. Pg. 5 Regulatory Compliance reference updated. Pg. 5 ZO104KCE data updated. Pg. 5 High-pressure relief valve settings changed. Pg. 6 Modified low pressure cut. Pg. 7 Charging Procedures changed Pg. 9 Maintenance and Repair section added
Pg. 10 Table of AE-Bulletins and documentation related with this Bulletin. Pg. 10 Nomenclature details added. Pg. 10 Oil and Refrigerant table added Pg. 10 Crankcase kit table added Pg. 11 OMC CO2 Specification Chart added Pg. 11 Drawing of Subcritical DX System changed. Pg. 11 and Pg. 12 Mounting parts drawings added. Pg. 11 Oil Management drawing added Pg. 13 Pressure Relief Valve drawing changed. Pg. 14 Operating Envelop changed.
Revision Tracking R5
Pg.6 Added CO2 OMB Oil Management Links
Copeland Scroll™ Compressors for CO2 Subcritical Refrigeration (R-744)
August 2019
AE4-1372 R5
© 2019 Emerson Climate Technologies Inc.
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AE4-1372 R5
Safety Instructions
Copeland Scroll™ compressors are manufactured according to the latest U.S. and European Safety
Standards. Particular emphasis has been placed on the user's safety. Safety icons are explained below and safety instructions applicable to the products in this bulletin are grouped on Page 3. These instructions should be retained throughout the lifetime of the compressor. You are strongly advised
to follow these safety instructions.
Safety Icon Explanation
DANGER indicates a hazardous situation which, if not avoided, will result in death or serious injury.
WARNING indicates a hazardous situation which, if not avoided, could result in death or serious injury.
CAUTION, used with the safety alert symbol, indicates a hazardous situation which, if not avoided, could result in minor or moderate injury.
NOTICE is used to address practices not related to personal injury. CAUTION, without the safety alert symbol, is used to address practices not related
to personal injury.
FLAMMABLE
PRESSURE indicates a dangerous proximity to high pressure section of the system.
DANGER
WARNING
CAUTION
NOTICE
CAUTION
© 2019 Emerson Climate Technologies Inc.
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AE4-1372 R5
Instructions Pertaining to Risk of Electrical Shock, Fire, or Injury to Persons
WARNING
ELECTRICAL SHOCK HAZARD
• Disconnect and lock out power before servicing.
• Discharge all capacitors before servicing.
• Use compressor with grounded system only.
• Molded electrical plug must be used when required.
• Refer to original equipment wiring diagrams.
• Electrical connections must be made by qualified electrical personnel.
• Failure to follow these warnings could result in serious personal injury.
PRESSURIZED SYSTEM HAZARD
• System contains refrigerant and oil under pressure.
• Remove refrigerant from both the high and low compressor side before
removing compressor.
• Never install a system and leave it unattended when it has no charge,
a holding charge, or with the service valves closed without electrically locking out the system.
• Use only approved refrigerants and refrigeration oils.
• Personal safety equipment must be used.
• Failure to follow these warnings could result in serious personal injury.
BURN HAZARD
• Do not touch the compressor until it has cooled down.
• Ensure that materials and wiring do not touch high temperature areas of
the compressor.
• Use caution when brazing system components.
• Personal safety equipment must be used.
• Failure to follow these warnings could result in serious personal injury or
property damage.
CAUTION
COMPRESSOR HANDLING
• Use the appropriate lifting devices to move compressors.
• Personal safety equipment must be used.
• Failure to follow these warnings could result in personal injury or
property damage.
Safety Statements
• Refrigerant compressors must be employed only for their intended use.
• Only qualified and authorized HVAC or refrigeration personnel are permitted to install commission and
maintain this equipment.
• Electrical connections must be made by qualified electrical personnel.
• All valid standards and codes for installing, servicing, and maintaining electrical and
refrigeration equipment must be observed.
WARNING
WARNING
© 2019 Emerson Climate Technologies Inc.
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AE4-1372 R5
INTRODUCTION
This bulletin describes the operating characteristics, design features, and application requirements for all Copeland Scroll™ compressors for refrigeration applications using CO2 (R-744) for a subcritical operation. For additional information, please refer to the online product information accessible from the Emeson website at Emerson.com/OPI.
Increasing environmental concerns about the potential direct emissions from HFC-based refrigeration systems into the atmosphere have led system designers to revisit refrigerant R-744 (CO2). In comparison with HFC refrigerants, the specific properties of CO2 require changes in the design of the refrigeration system. The ZO range of Copeland Scroll compressors has been designed to exploit the characteristics of CO2 refrigeration systems. The efficiency, reliability and liquid handling advantages of Copeland Scroll technology make it ideal for these applications.
The comparably high pressure level and thermodynamic properties of the refrigerant CO2 have driven system designers towards low temperature cascade systems, where CO2 is used as a direct expanding refrigerant in the low temperature stage. In these subcritical cascade applications, the CO2 compressor in the low temperature stage is still exposed to pressure levels higher than in standard HFC-based systems. However, they are limited to pressure levels similar to those already known from air-conditioning applications with refrigerant R-410A. An HFC refrigerant is typically used in the medium temperature stage of the cascade system.
The challenges for CO2 compressors compared to HFC compressors lie in the high pressure levels, the higher mass flow for a given displacement, and designing for proper lubrication. In terms of mechanical strength, ZO scroll compressors benefit from many years of experience with R-410A air-conditioning compressors, which operate at similar pressure levels as CO2 compressors.
CO2 FOR LOW TEMPERATURE APPLICATIONS SUB-CRITICAL DX SYSTEM
Figure 1
at the end of this bulletin shows a cascade system diagram with HFC refrigerant for the high side and sub-critical CO2 for the low stage refrigerant.
Nomenclature
The model designation contains the following technical information about the compressor:
ZO D 34 K 3 E - TFD - 269 Z
= Compressor family: Scroll
O
= Refrigerant: R744, subcritical operation
D
= Digital Model; Blank= Standard Model
34K
= Nominal Capacity (kBTU/hr)
3
= Model variation
E
= Oil type: POE oil
TFD
= Electrical Description:
T=
Three Phases
F
= Internal Inherent Motor Protection
5,7,D,E
= Nominal Voltage Range
269
= Bill of material
Please refer to Online Product Information at
Emerson.com/OPI
for details.
Refer to
Table 1
for a detailed list of ZO Family Models.
Approved Oils & Refrigerants
Recommended quality for carbon dioxide purity
grade is 4.0 [(≥ 99.99 %) H2O≤10ppm, O2≤10ppm,
N2≤50ppm] or higher.
Emkarate RL 68 HB is approved for new and service applications. Oil recharge values can be taken from
Copeland Scroll™ compressors brochures or
Copeland® brand Products Selection Software.
The compressor superheat at suction should be controlled such that it is always above 36°F (20K) to avoid oil dilution in the compressor but low return gas temperature enough to keep the compressor discharge temperature below 250°F (121.1°C), especially at high compressor ratios (high condensing and low evaporating temperatures).
Note:
A separate heat-exchanger may be required
to maintain the recommended superheat.
Refer to
Table
2 for reference.
Mounting Parts
Specially designed rubber grommets are available for mounting (Kit 527-0157-00). These grommets are formulated from a high durometer material specifically designed for refrigeration applications. The high durometer limits the compressors motion thereby minimizing potential problems of excessive tubing stress. Sufficient isolation is provided to prevent
CAUTION
© 2019 Emerson Climate Technologies Inc.
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AE4-1372 R5
vibration from being transmitted to the mounting structure.
The use of standard soft grommets is not recommended
.
Refer
Figure 2
for details.
Safety Relief Valves
In a closed system filled with CO2 the pressure can rise above 725 psig (50 Bar) under some ambient conditions. The system must be equipped with safety
relief valves to ensure that the compressor’s low side
and high side pressures are not exceeded (see below). If the unit is shut down for service or other reasons, the pressure will rise due to ambient heat. To prevent the loss of charge at shut down through the relief valves, it is recommended to provide additional cooling to keep the pressure below the maximum standstill pressure of the suction side. This can be achieved using a small auxiliary condensing unit connected to an uninterruptable power supply, that removes heat from the R744 liquid receiver. The auxiliary condensing unit will not be sufficient to maintain the low-stage system below the Maximum Allowable Operation Pressure if there is a load from the evaporators.
Refer to ANSI/ASHRAE Standard 15-2016, Section
9.7.5 and ANSI/ASHRAE 15 appendix C-2016,. ZO Maximum Operating pressures
Suction side 500 psig (34.5 Bar) Discharge side 625 psig (43.1 Bar)
The requirements for Copeland Scroll compressors with CO2 per Underwriters Laboratory (UL) state that a system with a CO2 compressor must be installed with an approved suction pressure relief valve. ASME high­pressure relief valves are the only valves currently approved for use with the Copeland Scroll CO2 models. The installation of the above valve must meet the following criteria:
1. There must be an open flow path from the compressor suction sump to the relief valve. This is accomplished by connecting the relief valve to the correct port on the suction Rotalock valve. This port is open to the compressor sump no matter what position the valve stem is located. The relief valve itself can be remotely located as long as the path from compressor suction sump and the valve is always open.
2. This flow path cannot be shut off in any way by a valve.
Figure 4
represents the correct (a) and incorrect (b) way to apply the pressure relief valve. Failure to apply the high-pressure relief valve correctly will void any UL approval of the system.
The high-pressure relief valve should be located such that the path between the valve and the low side of the compressor is always open and cannot be shut off in any way by a valve.
Note that the valve opens only
once and must be replaced if it opens.
A 500 psig (34.5 Bar) high-pressure relief valve kit is shipped with the compressor. Contact Application Engineering for alternative pressure relief valves.
ZO compressors have Rotalock valve fittings. Rotalock shut-off valves are available for the suction as well as discharge side. Using either straight or angled adaptors provides a way to convert a Rotalock into a brazing connection.
Tightening Torques
Torque
Lbs
Rotalock 1"-1 UNF
60-70 ft.lb.
Rotalock 1"1/4-12 UNF
75-85 ft.lb
High-Pressure Safety Controls
A CO2 approved ASME safety pressure relief valve(s) with a setting of 500 psig (34.5 Bar) is required to be pre-installed for standstill conditions.
All sections that can be isolated in the system must have relief valves pre-installed by the system manufacturer with a 500 psig (34.5 Bar) setting.
These high-pressure cut-outs should have a manual reset feature.
Additional Requirements:
Low Pressure Cut-Out on Suction Side: 80 psig (5.5 bar)
High Pressure Cut-Out on Discharge Side: 625 psig (43.1 Bar)
Discharge Temperature Protection
External discharge line thermostat 998-7022-02
Active Oil Management
An OMC CO2 electronic oil level management system should be used that is suitable for both high and low
CAUTION
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