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

Page: 78 / 126

Start the appliance (see section 4.1).
The appliance will now run the heating cycle (see section 4.1.1).
Read the pressure from the meter at the moment when the appliance switches from
PRE PURGE to PRESSURE SWITCH. At this point, the appliance's display will show:
Check whether the measured value matches the value from the table (see section
12.1).
Note
If the message PRESSURE SWITCH does not appear, there is a fault. This must be
resolved first by a qualified service engineer.
Shut off the gas supply.
Disconnect the pressure gauge.
Put the two black caps back on the pressure switch.
Replace the covers.
7.9.6 Turn on the water heater
Refer to the procedure in the user part to Turn on the water heater (see section 4.1).
7.10 Decommisioning
To decommission the water heater:
Turn off the water heater (see section 7.10.1)
Drain the water heater
7.10.1 Turn off the water heater
Refer to the procedure in the user part to Turn off the water heater (see section 4.2) and
isolate the water heater from the mains power supply.
7.10.2 Draining
7.10.2.1 Draining unvented installations
Some service activities require the water heater to be drained. The procedure is as
follows:
Activate the MENU with [ ].
Position the cursor in front of OFF.
Confirm OFF with [ENTER].
Wait until the fan has stopped. The icon is then dimmed.
Caution
Failure to wait until the fan stops can cause damage to the water heater.
Switch the water heater OFF (position 0) using the control switch on the operator
interface.
Isolate the water heater from the power supply by setting the isolator between the
water heater and the mains power supply to position 0.
Shut off the gas supply (10).
Close the stop valve (11) in the hot water pipe.
Close the supply valve (4) in the cold water inlet (A).
8.
9.
10.
11.
n
12.
13.
14.
15.
1.
2.
1.
2.
3.
4.
c
5.
6.
7.
8.
9.
78 Installation, Maintenance and Service part