Baxi PRIME HT 240 Installers And Users Instructions page 19

b) with QAA73 temperature regulator:
The temperature curve "kt" must be selected by setting parameter 70 "HC1 gradient" of the QAA73 temperature control
device as described in section 15.2 "QAA73: parameters which can be set by the installation engineer (service)".
See graph 3 for selecting the curve referred to a room temperature of 20°C.
The curve is shifted automatically on the basis of the room temperature set using the QAA73 climate control.
If the central heating system is divided into more than one zone, the temperature curve must be set on the QAA73 and in
the boiler (See section 26 for boiler settings.). The appliance's electronic control system provides a central heating output
temperature equal to the highest of the two values set on the QAA73 and in the boiler.
Graph 3
Graph 1
Graph 2
TM = Flow temperature
Te = Composite outside temperature
TM = Flow temperature
Te = Composite outside temperature
19
INSTRUCTIONS FOR THE INSTALLER