Honeywell EN2H-0221GE51 R0808 ユーザーズマニュアル

Hydraulic Components 

SDC / DHC  

160 EN2H-0221GE51 

R0808 

The simplest way of controlling the return flow temperature is by 
means of a bypass pump. When the return temperature in the 
heat generator drops below the set boiler return minimum 
temperature limit, flow mixing is initiated by switching on a bypass 
pump parallel to the heat generator. As soon as the return 
temperature rises above the return minimum temperature plus the 
return switching differential, the bypass pump will be deactivated 
after the set delay time (extended pump running time "bypass 
pump"). As the mixing itself is not controlled, the bypass cross 
sections must be taken into account for the system layout. 

When the switch-off condition is reached, the bypass pump is 
switched off with a time delay in accordance with the set value. 

 

To avoid intermittent operation of the bypass pump, the return 
sensor must always be positioned downstream of the mixing point 
for this mode of return temperature control. 

 

If the control unit is equipped with a mixed heating circuit output, 
this output can be programmed for controlled flow mixing. 

In this mode of return control the programmed mixed heating 
circuit adjusts the return temperature to the return temperature 
setpoint. The adjustment is independent of the status of any start-
up protection of the heat generator. The return sensor for this 
function is connected at the sensor input of the respective mixed 
heating circuit (e.g. flow sensor 1 for mixed heating circuit 1). 

The mixed heating circuit pump operates like a boiler circuit pump 
without boiler start-up protection for this purpose.