Boards that fail in the bathroom, not on the line - a 24-station dual-85 chamber with real 40A loads

Model: NL-DKBK-85

The problem

A control board that passes a few minutes of room-temperature power-on will meet its real enemies in a steamy bathroom: relay welding, electrolytic capacitor bulging and dead keys all erupt in the field, and one warranty swap costs more than a whole batch of incoming aging. The industry-standard dual-85 accelerated aging (85C and 85 percent RH) only counts with real loads attached - a board idling in the chamber never exposes relay welding - and hauling boards in and out by hand stretches a reliability programme over months.

Capability

Twenty-four test stations share one source across two drawer levels (twelve per level, anti-rust finish, 150mm side ports for wiring) with two stations wired out to the load cabinet. The chamber covers -40 to 150C (dual-85 at 85C and 85 percent RH) with fluctuation within 0.5C, uniformity within 2C and deviation within 1C; heating runs 3.0-5.0C per minute and cooling 2-4C per minute from 90C to -25C unloaded, driven by a two-stage refrigeration system with boiler humidification on deionised water. Humidity spans 20-98 percent RH. The bench suits control boards of 2-8.5kW storage and instantaneous water heaters and ships with thirty 2.5m high-temperature silicone test leads and universal fixtures. The load cabinet outputs 0-40A adjustable on two independent channels fed through circuit breakers, in a custom A3 enamelled wheeled cabinet with forced-air cooling. Programming stores more than 50 profiles with scheduled on/off, load switching and settable humidity ramps, covering constant climate, dual-85 and high-low cycling. Post-test analysis is built in: a transistor curve tracer (MOS, bipolar, thyristor; collector current to 50A; breakdown and reverse leakage to 5000V; sensitivity 0.5 microamp per division), a bench low-resistance meter (1 microohm to 20 kilohm, 0.05 percent, temperature compensated), a transformer tester, insulation resistance (1-800V, 0.01 megohm to 2 gigohm) and AC/DC withstand (to 5000V), plus a digital microscope for failure analysis. Control is PLC plus PC with full history storage and open serial/Ethernet protocols.

Key specifications

• Application: dual-85 reliability aging of water-heater control boards
• Stations: 24 on two drawer levels, 2 wired to external loads
• Temperature: -40 to 150C, dual-85 at 85C and 85 percent RH
• Temperature performance: fluctuation within 0.5C, uniformity within 2C, deviation within 1C
• Ramp rates: heating 3.0-5.0C/min; cooling 2-4C/min (90C to -25C unloaded)
• Humidity: 20 to 98 percent RH, error +2/-3 percent RH above 75 percent
• Chamber: 1200x800x1000mm internal, air speed 1.7-2.5 m/s
• Refrigeration and humidification: two-stage system; boiler humidification, deionised water loop
• Samples: control boards of 2-8.5kW storage and instantaneous water heaters
• Leads: thirty 2.5m high-temperature silicone leads with universal fixtures
• Load cabinet: 0-40A adjustable on 2 independent channels, forced-air cooled
• Programs: more than 50 stored, scheduled switching and humidity ramps

Applications

Incoming aging and type testing of control boards at water-heater plants; dual-85 accelerated verification by control-solution providers; laboratory capability building for appliance-controller test houses; outgoing reliability sampling at board plants

About the manufacturer

Guangdong Endurance Electronic Equipment Co., Ltd provides non-standard customization, drawing confirmation, factory acceptance, on-site installation and commissioning, operation training and long-term technical service; 12-month warranty and long-term spare parts supply. Tel: 0760-88500902 / 13416787649. Web: en.zsnaili.com.