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Danfoss Differential Oil Pressure Switch – MP Series
The Danfoss MP Series Differential Oil Pressure Switch is designed to protect refrigeration compressors against insufficient lubricating oil differential pressure. The range includes MP54, MP55, MP55A and MP55E for different compressor, refrigerant and application requirements.
MP Series MP54 MP55 MP55A MP55E Compressor Protection Oil Safety Control🛢️ Reliable Compressor Oil Pressure Protection
Proper lubrication is critical to the reliable operation of a refrigeration compressor. The Danfoss MP differential oil pressure switch monitors the effective lubricating oil pressure and protects the compressor if sufficient oil differential pressure cannot be maintained.
Rather than monitoring only the oil pump outlet pressure, the control responds to the difference between oil pressure and compressor crankcase / suction pressure.
The compressor requires sufficient net oil pressure to deliver lubricant to its moving components. If the effective oil differential pressure remains too low, the MP safety control can interrupt compressor operation according to the selected model and configuration.
📋 Danfoss MP Series – Available Models
The MP family includes several configurations for different refrigeration compressor and system requirements. Use the comparison below as a quick guide before selecting the exact Danfoss part number.
The MP54 is designed for compressor oil-safety applications requiring a fixed differential pressure setting.
Standard refrigeration compressor applications where a fixed oil differential setting is required.
The MP55 provides adjustable differential pressure control, allowing the oil safety setting to be selected according to the compressor lubrication requirements.
Commercial and industrial refrigeration compressors requiring an adjustable oil differential setting.
The MP55A provides adjustable differential oil-pressure protection and includes versions suitable for R717 ammonia refrigeration systems.
Industrial refrigeration and compatible ammonia refrigeration compressor applications.
The MP55E is a specialised oil differential pressure switch designed for applicable installations requiring an ATEX configuration.
Applicable refrigeration installations with special hazardous-area requirements.
🔍 Easy Model Selection
Fixed oil differential setting? → MP54
Adjustable oil differential setting? → MP55
Using R717 ammonia? → Check MP55A
Application requires the applicable ATEX version? → Check MP55E
✨ Key Features & Benefits
🛢️ Oil Pressure Monitoring
Monitors the effective lubricating oil differential pressure of compatible refrigeration compressors.🛡️ Compressor Protection
Helps protect the compressor against operation with insufficient lubricating oil differential pressure.⚙️ Fixed & Adjustable Options
MP54 provides a fixed differential arrangement, while MP55 and MP55A provide adjustable options.⏱️ Safety Function
Applicable versions use a thermal time relay so temporary oil-pressure conditions do not necessarily cause immediate compressor shutdown.❄️ Refrigeration Applications
Designed specifically around the oil-safety requirements of compatible refrigeration compressor systems.🧪 R717 Option
MP55A provides options suitable for compatible R717 ammonia refrigeration applications.⚙️ How a Differential Oil Pressure Switch Works
① Compressor Starts
The compressor starts and its lubrication system begins to develop oil pressure.② Oil Pressure Builds
The oil pump should generate sufficient pressure above the compressor crankcase or suction pressure.③ Differential Is Measured
The MP control responds to the difference between the two pressure inputs.④ Low Oil Differential
If the effective differential falls below the required level, the oil-safety function responds.⑤ Time Delay
Applicable MP versions allow a defined period for adequate oil pressure to be established or restored.⑥ Compressor Protection
If adequate oil differential pressure is not restored within the permitted period, the safety control can stop the compressor.⚠️ What Can Cause Low Oil Differential Pressure?
Low Compressor Oil Level
Insufficient oil in the compressor can prevent the lubrication system from maintaining adequate pressure.Oil Pump Problem
A worn, damaged or incorrectly operating oil pump can reduce effective oil pressure.Blocked Oil Path
Restriction in the oil circuit, strainer or related components can affect lubricant supply.Oil Foaming
Refrigerant dilution or foaming can interfere with stable oil-pressure generation.Excessive Bearing Clearance
Internal compressor wear may contribute to difficulty maintaining the required oil pressure.Incorrect Control Selection
An unsuitable differential setting or incorrect MP configuration may result in improper oil-safety operation.Repeated oil-pressure safety trips should not simply be reset without investigation. Check the compressor oil level, actual oil differential pressure, oil pump condition and lubrication system before returning the compressor to normal operation.
🏭 Typical Applications
❄️ Commercial Refrigeration
Oil-safety protection for compatible refrigeration compressors used in commercial systems.🧊 Cold Storage
Suitable for compressor lubrication protection in cold rooms, freezer rooms and cold-storage refrigeration plants.🏭 Industrial Refrigeration
MP55 and MP55A options can support larger and more demanding industrial refrigeration applications.🧪 Ammonia Refrigeration
MP55A provides solutions for compatible R717 industrial refrigeration applications.🥶 Low-Temperature Systems
Applicable to compatible compressors operating in low-temperature refrigeration installations.⚙️ Pressure-Lubricated Compressors
Designed for compatible refrigeration compressors using a pressure-fed lubrication system.📌 How to Select the Correct Danfoss MP Model
For replacement or new installations, do not select an MP oil pressure switch based only on appearance. Check the compressor and control requirements before ordering.
Identify the compressor manufacturer and complete compressor model number.
Confirm the refrigerant used by the refrigeration system, particularly for R717 applications.
Check the compressor manufacturer's required minimum lubricating oil differential pressure.
Determine whether a fixed or adjustable differential setting is required.
Verify the pressure connection type and size required by the installation.
Check the required electrical configuration, time relay and reset arrangement for the selected version.
Individual MP54, MP55 and MP55A part numbers can have different connections, differential settings, reset arrangements, time-relay characteristics and electrical specifications. Always verify the complete Danfoss part number and compressor requirements before replacing an existing control.
🔧 Replacing an Existing Oil Pressure Switch?
To help identify the correct Danfoss replacement, provide as much of the following information as possible:
📷 Existing Control
Provide a clear photo of the existing oil pressure switch and product label.🔢 Part Number
Provide the complete Danfoss part number if it is still visible.⚙️ Compressor
Provide the compressor brand and complete compressor model.🧪 Refrigerant
Confirm the refrigerant used by the system.Send us the existing Danfoss model / part number + compressor model + refrigerant. This gives our team the most useful information for checking the suitable replacement.
Danfoss Differential Oil Pressure Switch Supplier Malaysia
RNA Engineering & Trading Sdn Bhd supplies Danfoss MP Series differential oil pressure switches, refrigeration controls and HVACR spare parts for commercial refrigeration, cold storage and industrial refrigeration applications.
Contact us today for pricing, availability and technical enquiries.
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