Contents hide
1 Danfoss MTZ Reciprocating Compressors
2 Specifications
3 OVERVIEW
4 Descripation
5 Wiring
6 Introduction
7 Maintenance
8 Warranty
9 FAQs
10 Documents / Resources
10.1 References

Danfoss-logo

Danfoss MTZ Reciprocating Compressors

Danfoss-MTZ-Reciprocating-Compressors-product

Specifications

  • Model: MT / MTZ / NTZ / VTZ
  • Soft drinks
    • R22
    • R417A
    • R407A**
    • R407C
    • R407F**
    • R134a
    • R404A / R507
  • High Side Pressure Range: Varies based on model and refrigerant
  • Low Side Pressure Range: Varies based on model and refrigerant

OVERVIEW

Danfoss-MTZ-Reciprocating-Compressors-fig-1

Descripation

Danfoss-MTZ-Reciprocating-Compressors-fig-2

  • A: Model number
  • B: Serial number
  • C: Refrigerant
  • D: Supply voltage, Starting current & Maximum current
  • E: Housing service pressure
  • F: Factory-charged lubricant

Danfoss-MTZ-Reciprocating-Compressors-fig-3

  • Never operate compressors without a terminal cover fitted

Wiring

Danfoss-MTZ-Reciprocating-Compressors-fig-4

  • TH: Thermostat
  • SC: Start Capacitor
  • IOL: Motor Protector
  • SR: Start Relay
  • RC: Run Capacitor
 

Refrigerant Oil

 MT MTZ VTZ NTZ
R22 R417A R407A** R407C R407F** R134a R404A / R507 R407C R134a R404A/ R507 R404A/ R507
160P 160PZ * 160PZ 160PZ 160PZ 160PZ 160PZ 160PZ 160PZ 160PZ 160PZ
High side pressure range bar (g) 10.9 – 27.7 9.32 – 25.5 11.6 – 25.8 12.5 – 29.4 12.1 – 24 7.87 – 22.6 13.2 – 27.7 7.8 – 29.4 7.87 – 20.2 9.89 – 27.7 13.2 – 27.7
Low side pressure range bar (g) 1.01 – 6.89 0.54 – 5.66 0.53 – 5.94 1.43 – 6.55 0.99 – 6.25 0.06 – 4.72 1.04 – 7.2 1.43 – 6.55 0.64 – 3.88 1.04 – 6.06 0.05 – 3.34
  • When MT compressors are used with R417A, the factory-charged mineral oil 160P must be replaced by polyolester oil 160PZ.
  • R407A and R407F are not used for the Chinese market.

Installation and servicing of the compressor by qualified personnel only. Follow these instructions and sound refrigeration engineering practice relating to installation, commissioning, maintenance, and service.

  • The compressor must only be used for its designed purpose(s) and within its scope of application (refer to «operating limits»). Consult the Application guidelines and datasheet available from cc.danfoss.com.
  • The compressor is delivered under nitrogen gas pressure (between 0.3 and 0.7 bar) and hence cannot be connected as is; refer to the «assembly» section for further details.
  • Under all circumstances, the EN378 (or other applicable local safety regulation) requirements must be fulfilled.
  • The compressor must be handled with caution in the vertical position (maximum offset from the vertical: 15°)

Introduction

These instructions pertain to the Maneurop® MT, MTZ, VTZ & NTZ compressors used for refrigeration systems. They provide necessary informa-tion regarding safety and proper usage of this product.

Handling and storage

  • Handle the compressor with care. Use the dedicated handles in the packaging. Use the compressor lifting lug and use appropriate and safe lifting equipment.
  • Store and transport the compressor in an upright position.
  • Store the compressor between -35°C and 50°C.
  • Don’t expose the compressor and the packa-ging to rain or corrosive atmosphere.

Safety measures before assembly

  • Never use the compressor in a flammable atmosphere.
  • The compressor ambient temperature may not exceed 50°C during off-cycle.
  • Mount the compressor on a horizontal flat surface with less than 3° slope.
  • Verify that the power supply corresponds to the compressor motor characteristics (see nameplate).
  • When installing MTZ, VTZ, or NTZ, use equipment specifically reserved for HFC refrigerants that was never used for CFC refrigerants.
  • Use clean and dehydrated refrigeration-grade copper tubes and silver alloy brazing material.
  • Use clean and dehydrated system components.
  • The piping connected to the compressor must be fiexible in 3 dimensions to dampen vibrations.

Assembly

  • Slowly release the nitrogen holding charge through the Schrader port.
  • Remove the gaskets when brazing Rotolock connectors.
  • Always use new gaskets for assembly.
  • Connect the compressor to the system as soon as possible to avoid oil contamination from ambient moisture.
  • Avoid material entering the system while cutting tubes. Never drill holes where burrs cannot be removed.
  • Braze with great care using state-of-the-art techniques and vent piping with nitrogen gas flow.
  • Connect the required safety and control devices. When the Schrader port is used for this, remove the internal valve.

Leak detection
Never pressurize the circuit with oxygen or dry air. This could cause a fire or an explosion.

  • Do not use dye for leak detection.
  • Perform a leak detection test on the complete system.
  • The low side test pressure must not exceed 25 bar.
  • When a leak is discovered, repair the leak and repeat the leak detection.

Vacuum dehydration

  • Never use the compressor to evacuate the system.
  • Connect a vacuum pump to both the LP & HP sides.
  • Evacuate the system to a pressure of 500 μm Hg (0.67 mbar) absolute.
  • Do not use a megohmmeter or apply power to the compressor while it is under vacuum, as this may cause internal damage.

Electrical connections

  • Switch off and isolate the main power supply. See overleaf for wiring details.
  • The compressor is protected against excess current and temperature by an internal overload protector. Follow local regulations regarding power line protection. The compressor must be connected to earth.
  • All electrical components must be selected as per local standards and compressor requirements.

Filling the system

  • Keep the compressor switched off.
  • Fill the refrigerant in the liquid phase into the condenser or liquid receiver. The charge must be as close as possible to the nominal system charge to avoid low-pressure operation and excessive superheat.
  • Keep the refrigerant charge below 2.5 kg per compressor cylinder if possible. Above this limit, protect the compressor against liquid flood-back with a pump-down cycle or suction line accumulator.
  • Never leave the filling cylinder connected to the circuit to avoid overfilling.

Verification before commissioning

  • Use safety devices such as safety pressure switch and mechanical relief valve in compliance with both generally and locally applicable regulations and safety standards. Ensure that they are operational and properly set.
  • Check that the settings of high-pressure switches and relief valves don’t exceed the maximum service pressure of any system component.
  • A low-pressure switch is recommended to avoid vacuum operation. Minimum setting 0.1 bar.
  • Verify that all electrical connections are properly fastened and in compliance with local regulations.
  • When a crankcase heater is required, it must be energized at least 12 hours before initial startup and after prolonged shutdown.

Start-up

  • All service valves must be in the open position.
  • Balance the HP/LP pressure.
  • Energize the compressor. It must start promptly. If it does not, switch it off immediately. Possible single-phase miswiring can cause burnout within seconds.
  • If the compressor does not start, check wiring conformity and voltage on terminals.
  • If the internal overload protector trips out, it must cool down to 60°C to reset. Depending on ambient temperature, this may take up to several hours.

Check with the running compressor

  • Check the current draw and voltage.
  • Check suction superheat to reduce the risk of slugging.
  • When a sight glass is provided, observe the oil level at start and during operation to confirm that the oil level remains visible.
  • Respect the operating limits as printed overleaf.
  • Check all tubes for abnormal vibration. Movements in excess of 1.5 mm require corrective measures such as tube brackets.
  • When needed, additional refrigerant in the liquid phase may be added in the low-pressure side as far as possible from the compressor. The compressor must be operating during this process.
  • Do not overcharge the system.
  • Never release refrigerant to the atmosphere.
  • Before leaving the installation site, carry out a general installation inspection regarding cleanliness, noise, and leak detection.
  • Record type and amount of refrigerant charge as well as operating conditions, as a reference for future inspections.

Maintenance

  • Internal pressure and surface temperature are dangerous and may cause permanent injury. Maintenance operators and installers require appropriate skills and tools. Tubing temperature may exceed 100°C and can cause severe burns.
  • Ensure that periodic service inspections to ensure system reliability, and as required by local regulations, are performed. To prevent system-related compressor problems, the following periodic maintenance is recommended:
    • Verify that safety devices are operational and properly set.
    • Ensure that the system is leak-tight.
    • Check the compressor current draw.
    • Confirm that the system is operating in a way consistent with previous maintenance records and ambient conditions.
    • Check that all electrical connections are still adequately fastened.
    • Keep the compressor clean and verify the absence of rust and oxidation on the compressor shell, tubes, and electrical connections.

Warranty

Always transmit the model number and serial number with any claim filed regarding this product. The product warranty may be void in the following cases:

  • Absence of nameplate.
  • External modifications, in particular, drilling, welding, broken feet, and shock marks.
  • The compressor was opened or returned unsealed.
  • Rust, water, or leak detection dye inside the compressor.
  • Use of a refrigerant or lubricant not approved by Danfoss.
  • Any deviation from recommended instructions pertaining to installation, application, or maintenance.
  • Use in mobile applications.
  • Use in the explosive atmospheric environment.
  • No model number or serial number was transmitted with the warranty claim.

Disposal

  • Danfoss-MTZ-Reciprocating-Compressors-fig-5Danfoss recommends that compressors and compressor oil be recycled by a suitable company.

Danfoss can accept no responsibility for possible errors in catalogues, brochures, and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products already on order, provided that such alterations can be made without subsequent changes being necessary in specifications already agreed upon. All trademarks in this material are the property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

Danfoss A/S  6430 Nordborg, Denmark. Danfoss can accept no responsibility for possible errors in catalogues, brochures, and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products already on order, provided that such alterations can be made without subsequent changes being necessary in specifications already agreed upon. All trademarks in this material are the property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

FAQs

Q: Can I operate the compressor without the terminal cover?
A: Never operate compressors without the terminal cover fitted.

Q: What should I do if there is a leak in the system?
A: In case of a leak, repeat the leak detection process and take necessary actions to fix it.

Q: Can I connect dry air to the compressor?
A: Do not connect dry air to the compressor as it may cause a fire or an explosion.

Documents / Resources

Danfoss MTZ Reciprocating Compressors [pdf] Instructions
MT, MTZ, NTZ, VTZ, MTZ Reciprocating Compressors, MTZ, Reciprocating Compressors, Compressors

References

Leave a comment

Your email address will not be published. Required fields are marked *