1. Введение
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. Информация по технике безопасности
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.
- Убедитесь, что технические характеристики реле давления соответствуют требованиям системы.
- 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.
- При установке и обслуживании необходимо использовать соответствующие средства индивидуальной защиты (СИЗ).
The product label contains important safety information. Observe all warnings and instructions provided on the device itself.

Рисунок 1: Передняя часть 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. Что в коробке
После распаковки, пожалуйста, убедитесь, что все компоненты на месте и не повреждены:
- 1 unit of INSTRUKART MP-55 Oil Differential Pressure Switch
- Руководство по эксплуатации (данный документ)
4. Технические характеристики
| Параметр | Ценить |
|---|---|
| Номер модели | МП-55 |
| Диапазон дифференциального давления | от 0.30 до 4.50 бар |
| Contact Differential Pressure | 0.2 бара |
| Pressure Connection Size | ¼ дюйма |
| Pressure Connection Type | Вспышка |
| Максимальное рабочее давление | 17 бара |
| Максимальное испытательное давление | 22 бара |
| Диапазон температур окружающей среды | -40 °С до +60 °С |
| Совместимость хладагентов | HCFC and non-flammable HFC refrigerants |
| Функция сброса | Manual Min |
| Relay Release Time | 90 секунд |
| Electrical Connection Size | Стр. 13.5 |
| Тип электрического соединения | Screwed Cable Entry |
| Томtage | 230 V or 115 V AC or DC Supply |
| Рейтинг корпуса | IP20 |
| Вес товара | 0.74 кг |
| Производитель | ИНСТРУКАРТ |
Функции:
- 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. Установка
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 Механическая установка
- Монтаж: Select a suitable location for mounting the pressure switch, ensuring it is protected from excessive vibration, moisture, and extreme temperatures outside its operating range.
- Соединение давления: 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.
- Ориентация: 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 Электромонтаж
- Отключение питания: Ensure all power to the compressor and control circuit is disconnected and locked out before beginning electrical work.
- Проводка: 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.
- Заземление: Ensure proper grounding of the unit as per electrical safety standards.
- Кабельный ввод: Secure the cable entry to maintain the IP20 enclosure rating and prevent moisture ingress.

Рисунок 3: Сторона view of the MP-55, highlighting the electrical connection area. Proper wiring is essential for safe and reliable operation.
6. Операция
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 Нормальная работа
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 Ручной сброс
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.

Рисунок 4: Наклонный view of the MP-55, indicating the location of the manual reset button. This button should only be engaged after troubleshooting.
7. Техническое обслуживание
The INSTRUKART MP-55 is designed for reliable operation with minimal maintenance. However, periodic checks are recommended to ensure continued performance and safety.
- Визуальный осмотр: Regularly inspect the pressure switch for any signs of physical damage, corrosion, or loose connections.
- Проверка на герметичность: Periodically check the pressure connections for refrigerant or oil leaks.
- Электрические соединения: Убедитесь, что все электрические соединения надежны и не подвержены коррозии.
- Тест функциональности: 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.
- Уборка: 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. Поиск Неисправностей
Before attempting any troubleshooting, ensure all power to the system is disconnected. Only qualified personnel should perform troubleshooting and repairs.
| Проблема | Возможная причина | Действие |
|---|---|---|
| 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 voltagэлектронная поставка. |
If the problem persists after following these steps, contact INSTRUKART customer support or a qualified service technician.
9. Приложение Exampле
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
- Коммерческие системы кондиционирования воздуха
- Deep Freeze and Cold Storage Facilities

Рисунок 5: Визуальный примерamples of environments where the MP-55 oil differential pressure switch is typically utilized, demonstrating its broad applicability.
10. Гарантия и поддержка
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.
Производитель: ИНСТРУКАРТ
Модель: МП-55
ASIN: B0DCTXPHHM
Дата первой доступности: 11 августа 2024 г.





