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

7.8.3
7.8.3.1
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7.8.3.2
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7.8.3.3
7.8.3.4
0311753_SGS_28-120_II_UKUK_V2.0 , 2017-05-03

Optional electrical connections

Optionally, it is possible to:
• Connect an isolating transformer (see section 7.8.3.1).
• Connect a program-controlled pump (see section 7.8.3.2).
• Connect an external ON mode switch (see section 7.8.3.3).
• Connect an additional error signal (see section 7.8.3.4) to the water heater.
Isolating transformer
For more information about an isolating transformer, or to order an isolating transformer,
please contact A.O. Smith.
An isolating transformer should be used if there is a case of 'floating neutral'.
Note
The total power consumed by the appliance goes via the isolating transformer.
1. Refer to the fitting instructions provided with the isolating transformer. (Contact the
supplier for details of the correct isolating transformer.)
2.
Connect the neutral (N), live (L) and earth (A) of the power cables to terminals 4
through 9 of the connection block according to the table (see section 7.8.1).
3. Fit the cables in the strain relief.
4. If you have no more connections to make:
- Fit the cover on the terminal block.
- Fit the covers onto the water heater.
5. Connect the power cable to the isolator.
Program-controlled pump
Note
The maximum power capacity for a pump regulated by the controller is 100W.
1.
Connect neutral (N), live (L) and earth (A) to terminals 13, 14 and 15 as indicated in
the table (see section 7.8.1).
2. Fit the cable in the strain relief.
3. If you have no more connections to make:
- Fit the cover on the terminal block.
- Fit the covers onto the water heater.
External ON mode switch
External ON/OFF is an option for connecting an external ON/OFF switch. In the OFF
position, the programmed operating mode is active. In the ON position, the programmed
operating mode is overruled, and "ON mode" is active.
1. Connect leads (X3 and X4) to terminals 21 and 22 according to the table (see section
7.8.1).
2. Fit the cable in the strain relief.
3. If you have no more connections to make:
- Fit the cover on the terminal block.
- Fit the covers onto the water heater.
Additional error signal
The appliance has a relay terminal that is switched when an error is detected. This can be
used to signal errors, for example with a bulb. A 230V circuit can be powered directly.
Other voltages require a relay prescribed by the manufacturer.
1. Connect the phase cables (X1 and X2) to points 10 and 11 according to the table
(see section 7.8.1). If required, connect earth (A) to terminal 12.
2. Fit the cable in the strain relief.
3. If you have no more connections to make:
- Fit the cover on the terminal block.
- Fit the covers onto the water heater.
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