When an OEM customer asks for a custom temperature controller, the project moves fastest when key specifications are confirmed upfront. Here are the four things we need to know before we start —prepare these and you'll get a concrete proposal within 48 hours.
1. Load Types → Output Channels
List every load the controller must switch. Each load needs its own relay output:
- Compressor —always required
- Evaporator Fan —often delayed after defrost
- Lighting —internal cabinet LED or fluorescent
- Defrost —electric heater or hot-gas valve
- Defog —glass-door heater wire
Quick match: KY-370 (1 output), KY-371 (2 outputs), KY-533 (4 outputs), KY-566 (5 outputs incl. defog).
2. Load Power → Relay Rating
Undersized relays are the #1 cause of field failures. Provide running wattage and startup current for each load —especially compressors (locked-rotor current can be 5–7× running current) and defrost heaters (high inrush when cold).
| Load | Typical Current (220V) | Recommended Relay |
|---|---|---|
| Compressor (1/8–1/3 HP) | 0.5–1.5A run, 4–8A start | 16A |
| Evaporator Fan | 0.05–0.15A | 5A |
| LED Lighting | 0.02–0.2A | 3–5A |
| Defrost Heater | 1–7A (200–1500W) | 10–16A |
| Defog / Door Heater | 0.05–0.5A | 3–5A |
3. Cutout & Mounting Style
All Kaiyuan controllers use the industry-standard 71.5 × 30 mm cutout. The bigger decision is integrated vs. split-type:
| Integrated (KY-533) | Split-Type (KY-566 + Power Box) | |
|---|---|---|
| Depth behind panel | 50–60 mm | 20–30 mm (display head only) |
| Best for | Kitchen cabinets, worktables, island freezers | Glass-door display cases, bakery cases, convenience store multi-deck |
| EMC immunity | Good | Superior (power box separated from display) |
| Service | Replace whole unit | Replace display head without touching power wiring |
4. Functions & Parameters
Confirm which functions you need, and share parameter values from your existing mass-production units —we'll use them as defaults:
- Temperature range —standard −45 to +60°C (−40 to +99°F)
- Temperature compensation —calibration offset (±5°C, 0.1°C step)
- Defrost params —interval, duration, fan delay, drip time
- °C / °F switching —for export markets (KY-566 supports this)
We maintain a parameter library from thousands of field units across kitchen cabinets, display cases, island freezers, and worktables. Share your equipment type and we'll recommend starting parameters, then fine-tune during prototype evaluation.
Your 4-Item Checklist
- Load types and how many need independent switching
- Running wattage + startup current per load; supply voltage
- Cutout dimensions, panel depth, integrated or split-type preference
- Required functions and default parameters from your production data
Send us these four items and we'll respond with a recommended model, custom firmware spec, face-label design, prototype timeline, and pricing —typically within two business days.