GB/T 22688-2022 in English

GB/T22688-2022 replaces the 2008 version of the standard and systematically revises the definition, classification, technical requirements and test methods of household pressure temperature controllers. The new standard increases the insulation resistance requirement from 50MΩ to 100MΩ and optimizes the electrical strength classification system (see Table 3).

1. Action temperature accuracy

Thermostat adjustment point deviation for refrigerators is ≤1.0K (P/D/H type), and the deviation for heaters varies from 3-12K according to the temperature range (see Tables 1 and 2). Temperature sensing package immersion depth requirements:

• Cooling type: capillary immersion ≥150mm
• Heating type: capillary immersion 50-100mm

2. Mechanical durability

The standard stipulates 6 durability levels (Table 4). The highest level F must pass 500,000 on-off tests. The operating temperature changes after the test:

• Damper type ≤1.5K
• Conventional type ≤3K
• High temperature expansion type ≤5%T (T is the maximum operating temperature)

Key points for design selection

1. Select the charging method according to the application scenario: G type (superheated steam) is suitable for temperature difference environment, LG type is suitable for cross temperature conditions
2. Liquid expansion type (Y type) is preferred for heating equipment, and its temperature rise disconnection characteristic is safer
3. In high humidity environment, the insulation resistance should be verified to be ≥20MΩ after the damp heat test

Testing precautions

• The heating and cooling rate needs to be controlled during the action temperature test: G charging ≤1K/min, other types ≤0.5K/min
• The periodic air pressure alternation method is recommended for durability testing (Formula 1-2 to calculate the pressure value)
• New materials need to undergo additional tracking resistance tests (PTI 175-600V four gears)