Siemens 125-1957 ユーザーズマニュアル

⎯

Siemens Building Technologies. Inc. 

Cooling Loop – maintains room temperature setpoint by turning valves on and off and using 
free cooling (mixed air control) when available. 

Auxiliary Loop – modulates the auxiliary loop using the auxiliary setpoint and discharge 
setpoint (2284). 

Mixed Air Loop – modulates the mixed air loop using the mixed air setpoint and mixed air 
temperature (2283). 

DX Loop – modulates the cooling loop using the control setpoint and room temperature 
(2284).  

Morning warm-up or cool-down occurs after the controller switches from night mode to day 
mode, upon power-up, or if the controller is reset. During morning warm-up or cool-down, the 
controller provides maximum heating or cooling with the outdoor air damper closed until the 
temperature of the space reaches setpoint. 

When a face-bypass configuration is used, the coils may be turned on and off with two-
position valves using DOs. 

If electric heat is used, it is controlled as follows:  

0% to 33% 

ON 

OFF 

OFF 

34% to 66% 

ON 

ON 

OFF 

67% to 100% 

ON 

ON 

ON 

In addition, no stage may turn on or off until the time delay has elapsed. Stage one will 
always be the first stage to turn on and the last stage to turn off. 

Day Mode – The fan is on all the time. 

Night Mode – The fan only operates when required for heating or cooling. 

A low temperature detection thermostat (LTDT) can be used to signal the controller when the 
temperature drops below the low temperature limit.