A.O. Smith BFC-120, Installation, User And Service Manual

Page: 70 / 126

7.8.4.8 Connecting Q/T sensor
Note
You can optionally add a Q/T sensor to the installation. This enables you to calculate the
energy contribution of the system. For more information or to order the Q/T sensor,
please contact your supplier.
Connect the 5V to J12-1.
Connect sensor S4 to J12-2.
Connect earth to J12-3.
Connect the "flow signal" to J12-4.
Fit the cable in the strain relief.
If you have no more connections to make:
Fit the covers over the controller.
7.9 Commissioning
To commission the water heater:
Fill the water heater (see section 7.9.1)
Check the supply pressure (see section 7.9.2)
Check the gas control valve pressure
Measure the CO
2
(see section 7.9.4)
Switch pressure measurement (see section 7.9.5)
Turn on the water heater (see section 7.9.6)
7.9.1 Filling
7.9.1.1 Filling unvented installations
Refer to the installation diagram when you fill the water heater:
Open the stop valve (11) in the hot water supply pipe.
If applicable, open the stop valves (4) of the circulation pipe (C).
Make sure that the drain valve (9) is closed.
Open the nearest hot water draw-off point (14).
Open the stop valve (4) of the cold water supply pipe (A). Cold water flows into the
water heater.
Fill the water heater until a full water jet flows from the nearest draw-off point. The
water heater is completely full.
Open all draw-off points to bleed the entire installation of air.
The water heater is now under water supply pressure.
Make sure that no water comes out of the expansion valve (15) or the T&P valve (3).
If water comes out:
Examine if the water supply pressure is greater than the specified value in the
Technical details. If necessary, install a pressure reducing valve (1).
Examine if the expansion valve in the protected cold supply set-up is installed
correctly and is not defect. If necessary, replace the expansion valve.
7.9.1.2 Filling vented installations
To fill the water heater, proceed as follows:
Open the stop valve (11) in the hot water pipe and, if present, the stop valves (4) for
the circulation pump (6).
Close the drain valve (9).
Open the nearest hot water draw-off point (14).
Open the stop valve (4) on the cold water side (A) so that cold water flows into the
water heater.
Completely fill the water heater. When a full water jet flows from the nearest draw-
off point, the water heater is full.
Bleed the entire installation of air, for example by opening all draw-off points.
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70 Installation, Maintenance and Service part