VDH ALFA 71 User Manual

User manual
ALFA 71 0/+150
Thermostat
VDH doc. 032181
Software: ALFA71NR

* Functions.

The ALFA 71 spec is a thermostat with one temperature sensor, one relay with function heating
on/off and one 0-10Vdc PI-output with function cooling. The power supply is 24Vac.

* Installation.

On the top side of the ALFA 71 spec is shown how the sensor, power supply, PI-output and relay
are to be connected.
After connecting the ALFA 71 spec to the power supply, a self test function is started. As this test
is finished the measured temperature appears in the display.

* Control.

The ALFA 71 spec thermostat can be controlled by four pushbuttons on the front. These keys
are;
SET - view / change the setpoint.
UP - increase the setpoint.
DOWN - decrease the setpoint.
°F - hidden push button above the SET key and behind °F symbol.

* Viewing setpoint.

By pushing the SET key the setpoint appears in the display.
A few seconds after releasing the SET key the setpoint disappears and the measured temperature
is shown again in the display.

* Changing setpoint.

Push the SET key and the setpoint appears in the display. Release the SET key. Now push the
SET key again together with the UP or DOWN keys to change the setpoint. A few seconds after
releasing the keys the measured temperature shows again in the display.

* Status of the Outputs.

By pushing the hidden °F key the display shows the status of the outputs. The first segment
indicates the status of relay heating (1 = on, 0 = off)
The last two segments indicate the actual percentage of the PI-cooling output from 00 until 99%.
O
F 24Vac
Version: v1.0
File: Do032131.WP8
1
Datum: 06-10-2003
Range: 0/+150,0°F(1)