A.O. Smith SGS-28, Installation, User And Service Manual

Page: 68 / 126

7.8.3.5 Communication cable to solar heating system
You must connect a communication cable between the controllers of the water heater and
the solar heating system.
Connect the cables (X5 and X6) to terminals 23 and 24 as shown in the table (see
section 7.8).
Fit the cable in the strain relief.
If you have no more connections to make:
Fit the cover on the terminal block.
Fit the covers onto the water heater.
7.8.4 Electrical connection of the solar heating system
This section covers the following topics:
Preparation (see section 7.8.4.1);
Connecting the mains power (see section 7.8.4.2);
Connecting pump station - modulating pump (see section 7.8.4.3);
Connecting solar collector (see section 7.8.4.4);
Connecting tank sensor (see section 7.8.4.5);
Connecting top tank sensor (see section 7.8.4.6);
Connecting communication cable (see section 7.8.4.7);
Connecting Q/T sensor (see section 7.8.4.8).
7.8.4.1 Preparation
Remove the cover (snap-on type) from the terminal block for the collector. This has the
following terminals:
7.8.4.2 Connecting the mains power
Note
Just as with the water heater controller, the solar heating system controller must have a
permanent electrical connection to the mains power supply. There must be a double-pole
isolator installed in the permanent connection. This is the same double-pole isolator as
installed between the mains power supply and the water heater itself. Whenever this
isolator is operated, both controllers can be switched on or off.
Connect earth, live and neutral to terminals 1 through 3
Fit the cables in the strain relief.
Connect the power cable to the isolator.
Continue (see section 7.8.4.3).
7.8.4.3 Connecting pump station - modulating pump
The pump station contains a modulating pump (PWM controlled). You must connect this
pump to the controller of the solar heating system.
Connect earth, live and neutral to terminals 10 through 12.
Connect PWM and PWM+ to point 1 and 2 of J18.
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68 Installation, Maintenance and Service part