VDH ALFA 71 User Manual

User manual
ALFA 71 PI Spec.
Thermostat.
With solid state output
VDH doc. 080348
Software: 042779 ALFA71WA

* Installation.

On the top side of the ALFA 71 PI SPEC is shown how the sensors, power supply, relays and
0..10Vdc Solid-State output has to be connected. After connecting the ALFA 71 PI 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 PI 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.
 C - hidden push button above the SET key and behind  C symbol.

* Viewing setpoint.

By pushing the SET key the setpoint appears in the display. The decimal point of the last display starts
blinking. 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 Relays.

By pushing the hidden  C key the display shows the status of the relays. Each display segment shows
the status of the relay output, showing 0=off and 1=on. The code 110 means relay 1 and 2 are on and
relay 3 is off.

* Setting internal parameters.

Next to the adjustment of the setpoint, internal settings can be made like differential, sensor-offset,
setpoint range and the functions of the thermostat.
Push the DOWN key more than 10 seconds, to enter the 'Internal Programming Menu'. In the left
display the upper and lower segment are blinking. Over the UP and DOWN keys the required
parameter can be selected (see table for the parameters).
If the required parameter is selected, the value can be read-out by pushing the SET key. Pushing the
UP or DOWN key to change the value of this parameter.
If after 20 seconds no key is pushed, the ALFA 71 PI SPEC changes to the normal operation mode.
Version: v1.1
File: Do080348.wpd
1
Date: 08-10-2010
Range: -50/+50,0  C