How to inspect dehumidifiers, dehumidifier inspection standards and methods

With the rainy season approaching, the demand for dehumidification is surging. Dehumidifier quality is crucial, so what are the standards and methods for inspection?

Dehumidifier inspection is mainly based on GB/T 19411-2003 standard.

1. Appearance, packaging and labeling requirements

1. Product logo:

   • Each dehumidifier must have a durability label (in compliance with GB/T 13306) fixed in a conspicuous location (such as on both sides or the back).

   • The signage must include: Model name, main technical parameters (nominal dehumidification capacity, refrigerant type and charge amount, voltage/frequency/number of phases, total input power, weight), factory serial number, manufacturer name, and manufacturing date.

   • The working status signs (such as fan direction arrows, water inlet and outlet marks, instruments, and control button signs) must be clearly indicated.

   • There should be a clear trademark on the front of the product.

2. Packaging requirements:

   • Before packaging, the machine must be cleaned and dried, rust-prone parts must be coated with anti-rust agent, and refrigerant or nitrogen must be charged according to standards.

   • The machine is firmly fixed in the box and has reliable moisture-proof and shock-proof measures.

   • Required documents to accompany the box:

     • Certificate of Conformity: Contains model name, number, inspection results, inspector's signature, and date.

     • manual: Comply with the requirements of Appendix A of GB 9969.1-1998.

     • Packing List: List the manufacturer's name, model name, serial number, packing date, document list and quantity, and inspector's signature.

   • The packaging box is clearly marked:

     • Shipping and receiving mark: Recipient information, product model name, box size, gross/net weight, and shipper information.

     • Storage and transportation signs: Icons or words such as “Handle with care”, “Upward”, “Afraid of moisture”, “Number of stacking layers”, etc.

2. Technical specifications and inspection requirements

1. Basic manufacturing and appearance:

   • Conforms to GB/T 19411 and JB 8655 standards and is manufactured according to approved documents.

   • The surface of ferrous metal parts is treated to prevent rust.

   • Electroplating parts: Smooth, uniform color, free of peeling, pinholes, obvious spots or scratches. After the salt spray test, there shall be ≤2 rust spots/marks (area ≤1mm²/spot) per 100 cm² of the coating, and none if less than 100 cm².

   • Painted parts: There are no obvious bubbles, flow marks, missing coating, wrinkles or other damage. The number of falling grids after the paint film adhesion test is ≤15%.

   • Plastic parts: Smooth, uniform color, without cracks, bubbles, obvious shrinkage holes and other defects.

   • The components are installed firmly and reliably, and there is no friction or collision between pipeline parts.

   • The insulation layer has good performance, is non-toxic and odorless, and meets the requirements of GB 8624 flame retardant materials (Grade B1).

   • Refrigeration system materials must be resistant to refrigerants, lubricants and their mixtures to ensure normal operation.

2. Power supply and environment:

   • Power supply: single-phase 220V or three-phase 380V, 50Hz AC.

   • Temperature range:

     • The inlet air temperature must comply with regulations.

     • Temperature control type: water cooling inlet ≤ 34°C; air cooling inlet ≤ 43°C.

3. Parts requirements: All parts must comply with relevant standards.

4. Performance requirements (core indicators):

   • Nominal dehumidification capacity: The measured value is ≥ 95% of the nominal value.

   • Input power: Under nominal operating conditions, the measured value is ≤ 110% of the nominal value.

   • Dehumidification capacity per unit input power: The measured value is ≥ 95% of the standard value (Table 4).

   • Maximum load operation: Under the maximum load conditions specified in the standard, the machine should be able to start and operate normally. The overload protector should not operate during 1 hour of continuous operation (it is allowed to operate once within 5 minutes after stopping for 3 minutes and then restarting, and then continue to operate for 1 hour).

   • Low temperature operation: When operating at low temperature:

     • No water droplets are blown out of the air outlet.

     • At the end of the operation, there is no frost on the windward side of the evaporator.

     • For equipment with automatic defrost function, the defrost time shall be ≤ 30% of the complete test cycle.

   • Condensation: During the test, condensation should not drip from the external surface and the indoor air supply should be free of water droplets.

   • Refrigeration system sealing: No leakage in any part.

   • Condensate removal: When operating under various working conditions, the drainage is unobstructed and no water overflows or blows out of the drain outlet.

5. noise: For dehumidifiers with fans, the noise level (sound pressure level) must be ≤ the standard value (Table 5). Dehumidifiers without fans will not be assessed.

3. On-site inspection and testing items

1. Transport simulation (applicable to non-fragile items): Perform drop test (10 times) according to ISTA 1A standard. The product and packaging should have no fatal or serious defects.

2. Size/cable length/weight: Measure product dimensions, power cord length, and overall weight, and compare with specifications and samples. The default tolerance is ±3% (unless otherwise specified by the customer).

3. Barcode Verification: Scan the barcodes on the outer box and sales packaging to confirm that they are readable and the information is correct.

4. Assembly inspection: Assemble/install according to the instructions and the process should be smooth and problem-free.

5. Functional testing:

   • Test all declared features (such as dehumidification mode, timer, fan speed adjustment, compressor protection, low pressure start, etc.) to ensure they operate properly and as described.

   • (If equipped with a clock function) Check the clock accuracy: electronic clock ±1 minute, mechanical clock ±10 minutes (measured after 2 hours of operation).

   • Briefly power on and off the device 5 times to check functional stability.

6. Coating and label durability:

   • Coating Adhesion: When testing printing, hot stamping, UV coating, etc. using 3M tape, the peeling area is ≤10%.

   • Tag Friction: Wipe with a damp cloth for 15 seconds + wipe with a hexane cloth for 15 seconds (Note: the factory provides hexane. This test is for reference only and is not a laboratory substitute). The label should be intact.

7. Electrical safety testing:

   • High voltage test: Apply voltage according to product category (e.g. 1200V AC for US and Canadian markets; 1000V AC for European Class I/2500V AC for Class II) for 1 second, leakage current ≤ 5mA, no breakdown.

   • Ground continuity (if applicable): Apply test current (lamps: ≥10A, home appliances/US and Canada: 25A) for 1 second, and the ground resistance is ≤0.5Ω or 0.1Ω respectively.

   • Low voltage starting (motor type): It should be able to start normally at 90% of the rated voltage.

   • Boot aging: Run at full load at rated voltage for ≥4 hours (or the time specified in the instructions), and then pass high-voltage test, functional test, grounding test, etc.

8. Power consumption and input characteristics: Measure power consumption, input power, and input current to comply with specifications and safety standards.

9. Power Cord Strength:

   • IEC standards: Apply force according to the wire weight (30N for ≤1kg; 60N for >1kg≤4kg; 100N for >4kg) 25 times, with a displacement of ≤2mm.

   • UL Standard: Pull 35 pounds (about 155.7N) for 1 minute, and the line should not move.

10. Internal structure and key parts: Disassemble and inspect (according to CDF/CCL list) to confirm the internal workmanship (such as no cold welds, false solder joints, loose parts), wiring (smooth and without sharp edges), no internal foreign matter, and that key components meet the requirements.

11. Operating characteristics:

    • Fan speed (if applicable): The speed is measured at rated voltage and must meet the requirements.

    • Leakage check: Use a leak detector to check the pipes and compressor connection points to ensure there are no refrigerant leaks.

12. Stability (vertical product): Place it on a 10° slope (15° for heating appliances) with the power cord in the most unfavorable position. The appliance should not fall over.

13. Packaging strength: Stack the outer boxes to a height of 2.5 meters for 4 hours and check whether there is any obvious deformation or damage.