A.O. Smith Theta T 20 10, Installation, User And Service Manual

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Installation-, User- and Service Manual
64
2.4 Control of the Theta
dual service module
2.4.1
2.4.2
Legend
1. control
2. 3-way mixing valve
3. temperature sensor S
5
4. plate heat exchanger
5. heating pump
6. room thermostat
7. DHW-pump
8. stop valve
9. (manual) air vent
A cold water supply
B hot water supply
C heating supply pipe
D heating return pipe
Introduction
The Theta dual service module, consists out of various components which provide the
warming of the heating water, such as:

the controller;
 the 3-way mixing valve;

the DHW pump;
 the heating pump;
 the temperature sensor;
 the room thermostat.
Controller
The controller of the Theta dual service module (Heat Master for BFC and Solar Heat
Master for SGE and SGS) is the device that uses various temperature sensors and a
room thermostat to control various elements (3-way mixing valve, DHW-pump and
heating pump) of the Theta dual service module.
In addition to the control of various components, the controller has a number of other
functions, such as:
 protection of the DHW-pump and heating pump against seizing due to prolonged
arrest;
 monitoring the temperature of the heating system (2.5.3 "Temperature monitoring of
heating system");

prevention against legionella (2.5.4 "Legionelle prevention");

DHW detection for simultaneity) (6.4 "Simultaneity").
Example of Theta dual service installation in combination with a BFC
domestic hot water dual service heating
IMD-1123 R0