DORCHESTER DR-FC 25, Installation, Commissioning And Maintenance Instructions

Page: 31 / 98

Electrical connection
Instruction Manual DR-FC 31
is
In preparation you should first remove the two covers and the protective cap
of the electrical section. The covers are attached to the water heater by 4
screws and fastenings. The covers are also joined to each other with
fastenings.
1. Unscrew the screws of the covers.
2. Carefully remove the black covers from the water heater.
The electrical section is now visible.
3. Undo the 2 screws
1
from the electrical section and remove the protective
cap
2
from the electrical section.
The connection block
3
is now visible.
n
Remark
Refer to ’A.2 Electrical diagram DR-FC’ for the connection of electrical
components.
3.10.3 Mains voltage
The water heater is supplied without a power cable and isolator.
n Remark
In order to receive electrical power, the water heater has to be connected to
the mains voltage by means of a permanent electrical connection. A double
pole isolator with contacts gaps of at least 3 mm must be fitted local to the
water heater. The power cable must have cores of at least 3 x 1.0 mm
2
.
1. Connect phase (L), neutral (N) and earth (
A
) of the power cable to terminals
22 through 24 of the connector block as indicated in Table 3.9 .
2. Fit the power cable in the pull relief.
3. If you do not need to make any more connections:
- Fit the cap on the electrical connection block.
- Fit the covers onto the water heater.
4. Connect the power cable to the isolator.
Warning
Leave the water heater disconnected until you are ready to start it up.
5. If you do not need to make any more connections:
- Fit the cap on the electrical connection block.
- Fit the covers onto the water heater.
3.10.4 Isolating Transformer
An isolating transformer should be used if there is a case of “floating neutral”.
1. Refer to fitting instructions provided with the isolating transformer
(1)
.
2. Connect phase (L), neutral (N) and earth (
A
) of the power cables to
terminals 16 through 21 of the connector block as indicated in Table 3.9 .
3. Fit the cables in the pull relief.
4. If you do not need to make any more connections:
- Fit the cap on the electrical connection block.
- Fit the covers onto the water heater.
5. Connect the power cable to the isolator.
1. Contact Hamworthy for details of the correct isolating transformer.