Baxi PRIME HT 240 Installers And Users Instructions page 16

15.1 DESCRIPTION OF THE ELECTRICAL CONNECTIONS TO THE BOILER
Turn the control box downward to access terminal boards M1 and M2 used for the electrical connections by removing the
two protective covers (see figure 12).
Terminals 1-2, terminal board M1: room temperature thermostat "TA".
Terminals 4-5, terminal board M2: connections for the optional SIEMENS QAA73 temperature regulator. These connec-
tions do not have any specific polarity.
Remove the bridge between terminals 1-2 "TA" on terminal board M1.
Read the instructions provided with the temperature regulator to ensure correct installation and programming.
Terminals 7-8: connections for the optional SIEMENS QAC34 outdoor temperature sensor. Read the instructions provi-
ded with the outdoor temperature sensor to ensure correct installation.
Terminals 9-10: connections for the optional domestic hot water priority sensor, for connecting single system boilers to
external DHW boilers.
15.2 CONNECTING THE QAA73 TEMPERATURE REGULATOR
An optional interface card is required to connect the QAA73 temperature regulator to boiler's own electronic control card.
Connect the interface card to connector X 300 on the boiler's electronic control card (figure 13).
Terminals 1-2-3, terminal board M2: connections for a zone control solenoid valve (see figure 15 in section 15.4).
OPTIONAL INTERFACE
FOR QAA73
Figure 13
Domestic hot water temperature and timing must be programmed on the QAA73 temperature regulator.
The timed program of the central heating circuit must be set on the QAA73 if there is a single zone, or in relation to the
zone controlled by the QAA73 device.
See the instructions provided with the QAA73 temperature regulator for the user parameter programming procedure.
Screw
Cable guide
INSTRUCTIONS FOR THE INSTALLER
16
LEGEND:
N.C. - Normally Closed contacts
C - Common
N.O. - Normally Open contacts
WIRE COLOURS:
M
Brown
N
Black
C
Light blue
R
Red