

The ALC is at the heart of the controls package for most appliances.
From being as simple as an electronic thermostat, it can also incorporate analogue inputs (from temperature sensors, potentiometers, etc.), digital inputs (flow switches, pressure switches, safety stats etc.), digital outputs (mains and/or low voltage), and PWM outputs (suitable for DC fan drives, variable speed pumps, proportionating gas valves, etc.).
Typical Options |
|
NTC Thermistor Inputs: |
DHW, Flow, Return, Outside, and Flue temperatures |
Fan Output: |
Mains relay or DC fan speed controlled with tacho feedback |
Pump Output: |
Mains relay or PWM drive for Pump speed control |
FSC Output: |
Start burner signal from ALC (can be used with a separate FSC board) |
Diverter Valve/2nd pump: |
Mains relay |
DHW demand Input: |
Microswitch or flow rate transducer |
Safety Inputs: |
3 maximum (e.g. Overheat, DHW overheat, Low water pressure, APS) |
Burner on/lockout input: |
Opto-isolated signal from FSC |
Roomstat/programmer: |
Mains inputs from external controls |
Frost protection: |
2 stages, based on boiler water temperature |
Central Heating anti-cycling: |
Timed anticycle routines |
Load Antiseize: |
Timed antiseize routines for pumps, diverters, etc. |
Burner start-up: |
Ignition and cold start modulation fully programmable profiling |