101
Mixing valve control functions
SMGB0066 rev.0 - 12/2009
Controller pack
Service Manual
4
P33 Return Temperature Limit Offset (default OFF)
ItishighlyrecommendedforCONF2,thattheparameterP33is left in the default OFF state.
Recommended setting is 5K.
This function can be disabled by setting the parameter P33=OFF.
This function disables the electric heater control when the outdoor temperature is above the electric heater maximum
outdoor temperature setting. Above this setting it is assumed that the heat-pump is able to deliver all the requested heat
by itself and the electric heater is therefore not required.
P15 Maximum Outdoor Temperature for Electric Heater Operation (default 0°C)
Todisablethisfunctionandallowelectricheateroperationatalloutdoortemperatures,settheparameterP15=OFF.
Thisfunctiononlyappliestoconguration4(CONF4)
Whenheatingisrequired,theSystemControllercontrolsthemixingvalvesothatthemixedwatertemperatureiscloseto
the Supply Setpoint. The mixing valve position is calculated with a proportional plus integral action (P+I) control algorithm
based on the difference between the Supply Setpoint and mixed water temperature (TMIX).
Desired Mixing Valve Position = PI function ( Supply Setpoint – TRET )
The System Controller then decides how much to open or close the mixing valve to achieve the desired position of the
valve.Thisisdependentontherunningtimeoftheactuatorusedonthevalve.Therunningtimeisdenedasthetimeit
takes to drive the valve from the fully closed to the fully open position. Typically this can be between 1 and 4 minutes.
P9 Mixing Valve Runtime (default 120 sec)
EP1 Mixing Valve Integral factor (default 2.5)
The installer should set the parameter p9 based on his selection of actuator and mixing valve.
The value for EP1 has been chosen based on laboratory tests and it is not recommended to change it.
note
Engineering Parameters (EP) are only available for service engineers. -
To Next Page
Loading...
Need help?
General
