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Siemens
Room temperature controller with LCD
N3075en
Building Technologies
17.04.2009
Control sequences
On Q33-Q34 Q13-Q14
W
W
On Q13-Q14
W
= =
= =
= =
Application with heat pump for heating or cooling:
W
Room temperature setpoint
W
D
Switching differential between heating and auxiliary electric heating
SDH
Switching differential heating
SDC
Switching differential cooling
When used in connection with a heat pump, output Q13-Q14 (NO contact) must be
connected to the compressor’s control input.
Output Q21-Q22-Q24 must be connected to the compressor’s H/C control input.
Output Q33-Q34 (NO contact) is for connection to an auxiliary electric heater
(RDX43.2).
Button
is used for manual changeover from heating to cooling, or vice versa. The
factory setting of the changeover contact is “Open“ for heating and can be changed to
”Closed” for heating using parameter P18.
To avoid damage to the compressor during H/C changeover, a minimum compressor
on / off time can be adjusted via parameters P11 and P12. The factory setting for the
minimum on time is 1 minute and for the minimum off time 3 minutes.
Legend
Heating / cooling mode
Compressor on time
