INSTRUKART MP-55
INSTRUKART MP-55 Olie Differensiële Drukskakelaar Gebruikershandleiding
Model: MP-55 | Brand: INSTRUKART
1. Inleiding
The INSTRUKART MP-55 oil differential pressure switch is designed as a safety device for refrigeration compressors. Its primary function is to protect compressors from damage caused by insufficient lubricating oil pressure. In the event of an oil pressure failure, the MP-55 will initiate a compressor shutdown after a predetermined time delay.
This device is suitable for use in refrigerating systems that utilize HCFC and non-flammable HFC refrigerants. Common applications include HVAC systems, various industrial processes, air conditioning plants, and general refrigerating systems.
This manual provides essential information for the safe and effective installation, operation, and maintenance of your MP-55 pressure switch.
2. Veiligheidsinligting
WARNING: Improper installation, operation, or maintenance can result in serious injury or equipment damage. Read and understand all instructions before proceeding.
- Installation and service must be performed by qualified and authorized personnel only.
- Always disconnect power to the compressor and associated equipment before performing any installation, maintenance, or troubleshooting.
- Ensure proper handling of refrigerants according to local regulations and safety standards.
- Verify that the pressure switch specifications match the system requirements.
- Do not press the reset button without first identifying and rectifying the cause of the low oil pressure condition. Refer to operating instructions to avoid compressor damage.
- Dra gepaste persoonlike beskermende toerusting (PPE) tydens installasie en diens.
The product label contains important safety information. Observe all warnings and instructions provided on the device itself.

Figuur 1: Voorkant view of the MP-55 Oil Differential Pressure Switch. The label clearly indicates the model type, manufacturer, and critical safety warnings regarding the reset button in multiple languages.
3. Wat is in die boks
Maak asseblief seker dat alle komponente teenwoordig en onbeskadig is tydens uitpak:
- 1 unit of INSTRUKART MP-55 Oil Differential Pressure Switch
- Instructiehandleiding (hierdie dokument)
4. Tegniese spesifikasies
| Parameter | Waarde |
|---|---|
| Modelnommer | MP-55 |
| Differensiële drukreeks | 0.30 tot 4.50 bar |
| Contact Differential Pressure | 0.2 bar |
| Pressure Connection Size | ¼ duim |
| Pressure Connection Type | Opvlam |
| Maksimum werksdruk | 17 bar |
| Maksimum toetsdruk | 22 bar |
| Omgewingstemperatuurreeks | -40 °C tot +60 °C |
| Koelmiddelversoenbaarheid | HCFC and non-flammable HFC refrigerants |
| Herstel Function | Manual Min |
| Relay Release Time | 90 sekondes |
| Electrical Connection Size | Bl 13.5 |
| Tipe elektriese aansluiting | Screwed Cable Entry |
| Voltage | 230 V or 115 V AC or DC Supply |
| Omhulselgradering | IP20 |
| Item gewig | 0.74 kg |
| Vervaardiger | INSTRUKART |
Kenmerke:
- Fixed and adjustable differentials available.
- Extremely narrow switch differential accuracy.
- Reliable, long-life stainless steel bellows.
- Can be used for HCFC and non-flammable HFC refrigerants.
5. Installasie
Installation of the MP-55 pressure switch should only be carried out by certified refrigeration technicians or qualified electricians, adhering to all relevant local and national codes and standards.
5.1 Meganiese installasie
- Montering: Select a suitable location for mounting the pressure switch, ensuring it is protected from excessive vibration, moisture, and extreme temperatures outside its operating range.
- Drukverbinding: Connect the ¼ inch flare pressure connection to the oil pressure line of the compressor. Ensure a tight, leak-free connection using appropriate tools and sealing methods for refrigerant systems.
- Oriëntasie: The switch can typically be mounted in any position, but refer to the specific markings on the unit for any recommended orientation.

Figure 2: Detail of the ¼ inch flare pressure connection. This connection point is crucial for accurate oil pressure monitoring.
5.2 Elektriese installasie
- Kragontkoppeling: Ensure all power to the compressor and control circuit is disconnected and locked out before beginning electrical work.
- Bedrading: Connect the electrical wiring to the screwed cable entry (Pg 13.5) terminals according to the system's wiring diagram. The MP-55 supports 230 V or 115 V AC or DC supply.
- Aarding: Ensure proper grounding of the unit as per electrical safety standards.
- Kabelinvoer: Secure the cable entry to maintain the IP20 enclosure rating and prevent moisture ingress.

Figuur 3: Kant view of the MP-55, highlighting the electrical connection area. Proper wiring is essential for safe and reliable operation.
6. Operasie
The MP-55 functions by monitoring the differential pressure between the compressor's oil pump discharge and the crankcase pressure. A sufficient differential pressure indicates adequate oil lubrication.
6.1 Normale werking
During normal compressor operation, the oil differential pressure will be above the set point of the MP-55. The switch remains in a closed state, allowing the compressor to run.
6.2 Low Oil Pressure Detection and Shutdown
If the oil differential pressure drops below the set point (0.30 to 4.50 bar range), the MP-55 initiates a time delay. This delay (approximately 90 seconds) allows for transient pressure fluctuations without nuisance trips.
If the low oil pressure condition persists beyond the 90-second delay, the MP-55 will open its contacts, interrupting the compressor's control circuit and shutting down the compressor. This is a safety measure to prevent damage due to lack of lubrication.
6.3 Handmatige herstel
After a shutdown due to low oil pressure, the MP-55 requires a manual reset. The reset button should only be pressed after the cause of the low oil pressure has been identified and corrected. Repeatedly pressing the reset button without addressing the underlying issue can lead to severe compressor damage.

Figuur 4: Hoekig view of the MP-55, indicating the location of the manual reset button. This button should only be engaged after troubleshooting.
7. Onderhoud
The INSTRUKART MP-55 is designed for reliable operation with minimal maintenance. However, periodic checks are recommended to ensure continued performance and safety.
- Visuele inspeksie: Inspekteer die drukskakelaar gereeld vir enige tekens van fisiese skade, korrosie of los verbindings.
- Lekkontroles: Periodically check the pressure connections for refrigerant or oil leaks.
- Elektriese verbindings: Maak seker dat alle elektriese verbindings veilig en vry van korrosie is.
- Funksionaliteitstoets: As part of routine system maintenance, verify the proper functioning of the oil differential pressure switch and its associated safety circuit. This should be done by qualified personnel.
- Skoonmaak: Keep the exterior of the unit clean and free from dust and debris. Use a dry cloth for cleaning. Do not use abrasive cleaners or solvents.
8. Probleemoplossing
Before attempting any troubleshooting, ensure all power to the system is disconnected. Only qualified personnel should perform troubleshooting and repairs.
| Probleem | Moontlike oorsaak | Aksie |
|---|---|---|
| Compressor shuts down, MP-55 tripped. | Low oil differential pressure. | Check oil level, oil pump operation, oil filter, and system pressures. Rectify the cause before manually resetting the MP-55. |
| MP-55 does not reset after addressing the issue. | Faulty reset mechanism or internal damage. | Ensure the oil pressure has returned to normal. If it still doesn't reset, the unit may need replacement. |
| Compressor cycles frequently. | Intermittent low oil pressure, incorrect pressure switch setting, or faulty switch. | Monitor oil pressure. Verify switch settings. If issues persist, consult a technician. |
| No power to the MP-55. | Loose electrical connections, blown fuse, or circuit breaker trip. | Check wiring, fuses, and circuit breakers. Ensure proper voltage aanbod. |
If the problem persists after following these steps, contact INSTRUKART customer support or a qualified service technician.
9. Aansoek Examples
The INSTRUKART MP-55 is versatile and finds application in various industrial and commercial settings where refrigeration compressors are used. These include:
- HVAC (Heating, Ventilation, and Air Conditioning) systems
- Industrial Refrigeration Plants
- Commercial Air Conditioning Systems
- Deep Freeze and Cold Storage Facilities

Figuur 5: Visuele voorbeeldamples of environments where the MP-55 oil differential pressure switch is typically utilized, demonstrating its broad applicability.
10. Waarborg en Ondersteuning
For information regarding the warranty period and terms for your INSTRUKART MP-55 Oil Differential Pressure Switch, please refer to the purchase documentation or contact INSTRUKART customer support directly.
If you require technical assistance, have questions about installation, operation, or maintenance, or need to report a product issue, please contact INSTRUKART customer service through their official channels. Provide your product model number (MP-55) and purchase details when seeking support.
Vervaardiger: INSTRUKART
Model: MP-55
ASIN: B0DCTXPHHM
Eerste datum beskikbaar: 11 Augustus 2024
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