Walk-In Constant Temperature & Humidity Chamber For Reliability Testing

Model

SN886-25m³

Sample Restrictions

This test equipment is prohibited from testing or storing the following samples:

Flammable, explosive, or volatile substances

Corrosive substances

Biological samples

Strong electromagnetic emission sources

Nominal Volume

25m³

Inner Chamber Dimensions

W2500 × H2500 × D4000 mm

Outer Chamber Dimensions

W3550 × H3130 × D4650 mm

Test Environmental Conditions

Ambient temperature 5–35°C; relative humidity ≤85%RH; atmospheric pressure (86–106) kPa; chamber empty.

Applicable Test Standards

IEC 60068-2-78 Test Cab: Steady-State Damp Heat

Performance

Temperature Range

-30°C to +70°C

Temperature Fluctuation

≤ ±0.5°C

Temperature Deviation

±2.0°C

Temperature Uniformity

2.0°C

Temperature Rise Time

+20°C → +85°C ≤ 20 min (no load)

Temperature Fall Time

+20°C → -40°C ≤ 60 min (no load)

Humidity Range (Humidity Type Only)

Relative Humidity Deviation

±3%RH (＞75%RH, no load)
±5%RH (≤75%RH, no load)

Humidity Fluctuation

±2.5%RH

Air Velocity (center of chamber)

0.5–2.0 m/s (frequency adjustable).
All performance indicators must be met at air velocity ≤2.0 m/s.

Airflow direction

vertical downward

Working Heat Load (Heat Dissipation Capacity)

-40°C to +0°C: ≤2000 W

+0°C to +85°C: ≤6000 W

Structural Features

Thermal Insulation Structure

Composite modular panels consisting of:

Powder-coated galvanized steel (outer panel) → Thermal insulation material → SUS304 stainless steel (inner panel)

Outer panel: A3 cold-rolled steel, thickness ≥1.0 mm, HOHUXI standard color

Inner panel: SUS304, thickness ≥1.0 mm; floor with embossed anti-slip stainless steel

Insulation thickness: ≥100 mm

Floor load capacity: 1000 kg/m² (uniform load)

Floor: SUS304 embossed anti-slip steel plate, thickness 2.5 mm

Air Conditioning Channel

Centrifugal fans: ≥4 units
Heater, evaporator (also for dehumidification), water inlet/outlet, dry-bulb sensor
Humidity type chamber additionally includes: humidifier, anti-dry-burn protection

Standard Configuration

Cable ports: φ100 mm × 2 (left side), with caps and silicone plugs

Lighting: 60W/AC220V × 4, indicator tower light, buzzer, Pressure balance device

Door

Dual hinged double-leaf door

Single-leaf: H2000 mm × W1200 mm

Safety lock (openable from inside)

Heated anti-condensation double-glazed viewing windows (W400 × H600 mm ×2) 

Heated door frame

Control Panel

Temperature & humidity display controller, over-temperature protector, emergency stop, run indicator, fault indicator, buzzer

Mechanical Compartment

Refrigeration system, drain/water system, fans, electrical control cabinet, humidification & water control system

Electrical Control Cabinet

Cooling fans, distribution board, sample power terminals, RS-485 interface, main power breaker

Heater

316 stainless steel armored heater
Control method: SSR (solid-state relay) zero-crossing PWM

Humidification (Humidity Type Only)

Boiler-type steam humidification, 316 stainless steel heater
SSR PWM control
Water level control and dry-burn protection

Refrigeration System

Working Method

Compressor refrigeration system

Evaporator

Finned heat exchanger (also for dehumidification)

Condenser

Shell-and-tube or brazed plate heat exchanger

Expansion Device

Thermal expansion valve, capillary tube

Refrigeration Control

PLC automatically adjusts refrigeration conditions

Refrigerants

R404A, R23 (both with zero ozone depletion index)

Main Component Brands

Compressor

Bitzer (Germany, dual compressors)

Refrigerant

DuPont/Honeywell (USA)

Refrigeration Oil

American Arctic Bear/Honeywell

Pressure Switch

Danfoss (Denmark) / SAGInoMIYA (Japan)

Evaporator Pressure Regulato

Danfoss

Dryer Filter

Danfoss / Emerson (USA)

Expansion Valve

Danfoss / SPORLAN (USA)

Solenoid Valve

SAGInoMIYA (Japan) / ODE (Germany)

Oil Separator

Emerson

Electrical Control System

Display

7-inch TFT true-color LCD, 800×480 resolution

Operation Modes

Program and constant value

Setting Method

Touch panel, Chinese/English menu

Program Capacity

100 programs, each up to 10,000 steps, 9999 loops

Setting Range

Temperature: device range +5°C / –5°C extension
Humidity: 0–100%RH (humidity chamber)

Display Resolution

Temperature: 0.01°C
Time: 0.01 min
Humidity: 0.1%RH

Inputs

PT100 RTD, voltage, current (depending on configuration)

Communication

PC connection for curve display & data logging
Remote monitoring and control
Multi-chamber synchronization
RS-485, RS-232, Ethernet (choose one), USB 2.0

Control Method

Temperature: anti-integral-saturation PID + auto-tuning
Humidity: anti-integral-saturation PID + auto-tuning

Curve Recording

Battery-backed RAM
Recording interval: 1 s –120 s
Maximum history: 720 days (at 2 min interval)
Data retention ≥10 years (without power)

Additional Functions

Fault alarm with cause & troubleshooting guide
Power failure recovery
Upper/Lower temp limit protection
Timer (auto start/stop)
Self-diagnosis

Temperature & Humidity Sensors

Temperature: PT100 RTD
Humidity: Electronic humidity sensor

Electrical Component Brands

Power Switch

CHNT

AC Contactor

Schneider (France)

Thermal Relay

Schneider

Phase Sequence Relay

Schneider

High/Low Temp Protector

Yatai

AC Relay

Schneider / Fuji (Japan)

SSR

Yangming

Water Supply System (Humidity Type Only)

Water Supply Method

Pump lifting

Water Tank

Hidden type

Safety Protection Devices

Refrigeration System

Compressor overpressure
Compressor motor overheating
Compressor motor overcurrent
Cooling water low pressure

Humidification System (Humidity Type Only)

Low water level warning
Anti-dry-burn protection

Test Chamber

Adjustable high/low temperature limiter
Thermal fuse in test space
Air channel over-temperature protection
Fan motor overcurrent

Other

Phase sequence & phase loss protection
Leakage protection
Load short-circuit protection

Other Configurations

Sample Power Terminals

Relay-controlled, AC220V, within 2A
Closed during operation; open during stop or fault

Additional Items

Two internal sockets (10A), resistant to -30°C without cracking

Cooling Method

Water-cooled system (manufacturer provides cooling tower, water pump, and installation)