Premix Burner Coffee Roaster Technology in FOCHA Roasters

@mrcanumsu
Dec 23, 2025
3 min read

FOCHA uses the InfraMix premix burner—a compact, industrial-grade combustion system designed for stable heat, clean combustion, and controllable output. In simple terms: FOCHA’s roasting character starts with a burner that can mix fuel + air precisely, keep the flame tight and consistent, and respond smoothly when you adjust the heat.

What “Premix” Means (and Why It Matters in Roasting)

In a premix burner coffee roaster, heat input follows the roasting curve precisely, making thermal control predictable and repeatable even at low modulation levels. The blower pushes the air, the gas train injects fuel into the airflow, and the mixture is ignited on the combustion head.

Why that matters for FOCHA:

More stable combustion across low-to-high firing
Cleaner flame behavior (less “dirty burn” tendency when adjusted correctly)
Repeatable heat input = easier profiling and more consistent batch results

How a Premix Burner Coffee Roaster Works in FOCHA Systems

The CX-28/F is built around modulation (variable output):

Blower speed (RPM) controls combustion air delivery
A pneumatic proportional gas valve matches gas flow to the air pressure detected in the circuit
Output can be controlled via:
- 0–10 VDC or 4–20 mA analog signal
- PLC connection (industrial standard integration)

So instead of “on/off heat” behavior, you get a burner that can step through output smoothly, which is exactly what you want when you’re shaping development without shocking the roast.

The Combustion Head: Metal Fiber + Compact Flame Geometry

One of the strongest technical points in this burner is the metal fiber combustion surface.

What it does:

The air-gas mixture exits through many small holes and ignites on the surface
The flame stays perfectly retained and attached to the metal fiber at maximum firing
It supports high turndown ratios (up to 6:1) while reducing flashback risk at minimum firing
The flame is extremely compact, which helps prevent unwanted contact with appliance parts and reduces poor combustion risk

For FOCHA, that translates to: controlled, compact heat delivery that behaves predictably as you modulate.

Key Operating Targets (CX-28/F)

Category	Specification
Gas Type & Pressure	Natural Gas (G20): 21 mbar (diaphragm removed) LPG / Propane (G31): 31 mbar (diaphragm installed as per kit) Working pressure range: 12–60 mbar Maximum gas inlet pressure: 60 mbar (higher pressure may damage valve and components)
Electrical Supply	Monophase 220/230 VAC (±10%) Frequency: 47–65 Hz Typical power consumption (CX-28/F): 75 W
Thermal Capacity	Regulated output range: 4–28 kW (min/max) Maximum heat input: approx. 95,540 BTU/h
Environmental Conditions	Operating temperature range: 0°C to 60°C

Built-In Protection & Diagnostics (Because Real Life Happens)

The burner controller includes safety logic for ignition and operation:

Pre-purge, ignition attempts, lockout logic
Flame detection via ionization (and false flame detection)
Fan tacho monitoring (RPM verification)
High limit monitoring
Low mains voltage protection (example threshold noted: <157V triggers fault; resolves when mains returns to normal range)

This matters for FOCHA’s reliability story: you don’t just have a flame—you have a system that knows when something is wrong and forces safe behavior.

A Practical “FOCHA Advantage” Way to Say It

FOCHA’s heat isn’t just powerful—it's disciplined.The CX-28/F premix system is designed for stable combustion, clean modulation, and service-friendly diagnostics, so you can focus on roasting decisions instead of fighting unpredictable burner behavior.