Siemens Building Technologies
Basic Documentation REA22
Issue 2.0
CE1P2276E / 31.03.1999
Landis & Stefa Division
Description of heating engineer settings
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4.3
DIP switch 3
1
2
3
PID 12
PID 6
2-Pt
4
22
76Z
03
5°C
3°C
10°C
Self learning
The factory setting of all DIP switches is OFF.
If one or several DIP switch positions are changed, the reset button must be pressed as
confirmation. Otherwise the previous settings are still active!
4.3.1 Control
The REA22 is a two-position controller providing PID control. The room temperature is
controlled through the cyclic switching of a regulating unit.
The controller is supplied with an active self-learning mode, which enables it to auto-
matically adapt to the controlled system (type of building construction, type of radiators,
size of rooms, etc.). After a certain learning period, the controller optimizes its parame-
ters and then operates in the mode it has learned.
In exceptional cases, where the self-learning mode may not be adequate, it is possible
to choose PID 12, PID 6 or 2-Pt mode:
Mode with a switching cycle of 12 min for normal or slow controlled systems (e.g. mas-
sive building structures, large spaces, cast-iron radiators, oil burners).
Mode with a switching cycle of 6 min for fast controlled systems (e.g. light building
structures, small spaces, plate radiators or convectors, gas burners).
Mode with a pure two-position control with a switching differential of 0.5 °C (±0.25 °C)
for very difficult controlled systems with considerable outside temperature variations.
4.3.2 Frost
protection
Frost protection is adjustable with DIP switch 3 to either 3 °C, 5 °C (factory setting), or
10 °C.
Note
Self-learning mode
PID 12 mode
PID 6 mode
2-Pt mode
