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Siemens Switzerland Ltd
User manual RVS61.843 CE1U2355en_02
HVAC Products 6 The settings in detail 23. November 2007
• A process reversing valve must be configured
... cooling pipes … heating / cooling pipes ... heating / cooling pipes
Q9
Q8
B92
Y28
T
T
Q9
Q8
B92
Y28
T
B91
T
Y28
Q9
Q8
B92
Y28
T
B91
T
Y28
Passive cooling ON Passive cooling OFF Passive cooling OFF
Condenser pump OFF Condenser pump ON Condenser pump OFF
4-pipe system 2-pipe system 2-pipe system
Line no. Operating line
3000 Switch-off temp max cooling
3002 Source temp min cool mode
3004 SD ch’over cooling pas/act
3006 During compressor operation
3007 In passive cooling mode
3008 Temp diff cond cooling mode
If the return temperature (B71) lies above “Switch-off temp max cooling“, the
compressor must not be put into operation. If it is running, it will be switched off.
On completion of the set pump prerun times – but not before 2 minutes have elapsed –
the pumps are deactivated if the temperatures are still too high.
Another compressor startup attempt is made on completion of the minimum
compressor off time (2843).
This function is only active in the case of active cooling. It has no impact with passive
cooling. For more detailed information about active / passive cooling, refer to page 87.
To prevent the formation of ice in the heat exchanger for separating the media in
passive cooling mode, a minimum source temperature can be entered. If the
temperature at the source outlet sensor (B92) falls below the value set with parameter
“Source temp min cool mode”, the consumers will be locked until the source outlet
temperature exceeds the minimum temperature by 1 °C.
If the source temperature drops below the cooling setpoint minus the switching
differential set here and the minimum compressor on time has elapsed, the controller
switches to passive cooling.
SD ch’over cooling pas/act
Passive cooling via:
“During compressor
operation” (3006)
“In passive cooling
mode” (3007)
“Cooling circuit 1”
(5711)
Switch-off temp max
cooling
Source temp min cool
mode (frost protection)
SD ch’over cooling pas/act
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