Heating control

Construction manual

In the following we discribe, how to connect relays, LEDs, sensors and keys.

First we need a AVR-Control-PCB (or similar circuit; see the circuit diagram of the AVR-Ctrl).
Following parts we need:
Supply, microcontroller (with xtal,...),Display, Driver (ULN2803) for the Relays and
the Pullup-resistors for keys and analog Inputs (MAX232 if serial interface is needed).

Keys

Minu, plus and enter are used for the menu.

Mode changes the operation mode (Day, Absent, Night).

Relays 'Burner'

Theopener contact opens the supply of the burner . (As already discribed)
The "Burner" LED is on, if the burner has supply. The Switch is for switching into old heating mode without our control

Relays 'circulation pump'

Theopener contact opens the supply of the pump. (As already discribed)
The "Pump" LED is on, if the pump has supply. The Switch is for switching into old heating mode without our control

Temperature sensor 'boiler'

Temperature sensor 'Outside'

A shielded cable is recomended (Shield on GND).

A 1,5kOhm Pullup-Resistor is necessary. (Solder directly on the PCB)
Note: The Software has a very slow filter for the outside temperature: 0,1°C per minute.

Status-LEDs

The LEDs show the current operating mode.