I. Technical Features
This product line is positioned as a universal variable frequency solution, with its core design philosophy centered on "wide adaptability." Unlike the rigid operation of fixed-frequency units, the DHV series focuses on achieving linear cooling capacity output through AC variable frequency speed regulation. However, its unique value lies not only in energy saving, but also in its ultra-wide frequency operating range (typically covering 30Hz to 120Hz).
-
Operating Mechanism: This series features a specially optimized balance logic between low-frequency oil return and high-frequency oil supply. During low-frequency operation, the system utilizes a built-in centrifugal oil pump combined with differential pressure oil supply to ensure that a stable oil film still forms on the bearings at low speeds. This effectively avoids the industry-wide common issue of "low-frequency oil starvation and shaft burnout" in inverter compressors. Furthermore, to address high-frequency whistling, this series adopts a modified profile design for the asymmetric scroll plate. By altering the exhaust angle, it effectively reduces airflow pulsation noise during high-frequency operation.
-
Refrigerant Management: It is the most versatile platform among the three series in terms of refrigerant compatibility, covering a wide range from low-pressure (R134a) to medium/high-pressure (R404A/R507A) refrigerants. In cold storage retrofits or air conditioning refrigerant conversion projects, it can adapt to different refrigerants without replacing the compressor body, significantly reducing replacement costs.
-
Electrical Protection: It emphasizes tolerance to grid voltage fluctuations. The built-in PTC thermistor works in conjunction with the KRIWAN module. In addition to overheat protection, it also provides electromagnetic shielding against harmonic interference generated by the carrier frequency of the inverter, ensuring that the control board does not malfunction in complex electrical environments.
II. Scope of Application
Core Application Areas: Temperature and Humidity Regulation in Residential and Commercial Spaces
This series primarily serves building environment air conditioning systems that demand high comfort, quietness, and part-load energy efficiency:
Residential and Commercial Central Air Conditioning: Suitable for Variable Refrigerant Flow (VRF/VRV) air conditioning systems in residential communities, office buildings, hotels, shopping malls, and other venues. The inverter technology automatically adjusts the speed based on indoor and outdoor temperature differences, achieving low-energy consumption maintenance after rapid cooling/heating, with minimal temperature fluctuations and enhanced physical comfort.
Precision Environmental Air Conditioning: Meets the demands of scenarios requiring extremely high temperature control accuracy, such as data center server rooms, precision instrument rooms, and clean workshops. The smooth inverter output curve eliminates the temperature fluctuations caused by the frequent start-stop cycles of traditional fixed-frequency units.
After-Sales Maintenance and Replacement Market: Widely used in the after-sales maintenance and replacement market for VRF systems, it is a common choice for replacing old inverter compressors.
General Refrigeration Expansion: It can also be extended to heat pump systems and industrial, agricultural, and commercial refrigeration systems, though its core advantage remains concentrated in the field of building comfort air conditioning.
Typical Terminal Equipment: VRF outdoor units, modular air-cooled heat pump units, precision air conditioners for server rooms, and outdoor units for residential central air conditioning.
| External oil supply multi connected machine Multiple compressor unit by oil exterior(R22) |
| Specifications | Model | Refrigerant | Displacement | voltage | Frequency | Refrigeration capacity | Input power | EER/COP |
| cm³/rev | V | Hz | WATTS | BTU/H | WATTS | BTU/W.H | W/W |
| 4HP | 400DHM-64D1(2) | R22 | 64 | 380-415 | 50 | 11200 | 38190 | 3600 | 10.6 | 3.1 |
| 5HP | 500DHM-80D1(2) | 80 | 14000 | 47740 | 4300 | 11.1 | 3.25 |
| 6HP | 600DHM-90D1(2) | 90 | 15700 | 53540 | 4800 | 11.1 | 3.25 |
| frequency conversion | 401DHVM-64D1(2) | 64 | 160-380 | 20~115 | 16500 | 56270 | 5250 | 10.7 | 3.14 |
| 303DHV-47B2Y | 47 | 73-180 | 30-90 | 10700 | 36490 | 3370 | 10.9 | 3.2 |
| 303DHV-47D2Y | 47 | 146-360 | 10700 | 36490 | 3350 | 10.9 | 3.2 |
| 403DHV-64D2Y | 64 | 14200 | 48420 | 4300 | 11.2 | 3.3 |
| 503DHV-80D2Y | 80 | 135-360 | 17900 | 61040 | 5300 | 11.6 | 3.4 |
| 401DHV-64D2Y | 64 | 160-380 | 20~115 | 18000 | 61380 | 5600 | 10.9 | 3.2 |
Q1: The compressor noise increases significantly during operation. What should I do?
Symptoms: The compressor noise becomes louder after running for a period of time.
Possible Causes:
Oil shortage or insufficient lubrication — This is one of the most common faults, manifesting as excessive noise, seized cylinder, high operating current, etc.
High-frequency whistling — Inverter compressors may generate airflow pulsation noise during high-speed operation.
Solutions:
Check the oil level in the crankcase to ensure sufficient lubricating oil.
Check the oil level through the sight glass. If the oil level is significantly low, add oil promptly.
If it is high-frequency whistling, the DHV series itself has optimized high-frequency noise through its modified profile design of the asymmetric scroll plate. You can check whether the compressor is operating within an abnormal frequency range.
Q2: The compressor fails to start or trips frequently. How to troubleshoot?
Symptoms: No response, no pull-in sound, tripping.
Solutions:
Check whether the unit's power supply voltage is normal.
Check if the built-in motor overload protector has tripped. If so, allow the compressor to cool down sufficiently before it automatically resets.
Measure whether the motor winding resistance is balanced (the resistance between R-S, S-T, and T-R should be within a few ohms to several tens of ohms). Infinity indicates an open circuit, while 0 indicates a short circuit.
Check whether the indoor and outdoor fans are operating normally.
Q3: The oil level is significantly low but no oil leak point can be found. What is the reason?
Symptoms: Under normal load, the oil level in the crankcase is significantly low, the oil level in the unit's oil collector is excessively high, and oil sprays out when drained.
Possible Cause:
Solutions:
Check whether the built-in oil collector ball valve is not tightly closed (long-term inactivity may cause rust or accumulation of impurities on the valve and valve seat).
Perform grinding, cleaning, and repair on the ball valve. If it cannot be repaired, the ball valve can be welded shut (at which point the oil collector is decommissioned).
