A.O. Smith 120 through 250 Series - Manual (Page 55)

Instruction manual BFC 55
gis
9 Starting and running
9.1 Introduction
Topics covered in this chapter, in sequence:
•
Starting and running .
• The appliance's heating cycle .
9.2 Starting and running
Start the appliance as follows:
1. Fill the appliance
(5 "Filling") .
2. Open (3.5 "Installation diagram") the manual gas
valve.
3. Switch on the power to the appliance using the
isolator between the appliance and the power
supply.
4. Switch the electronic controller ON by setting the
ON/OFF switch to position I.
The display will now show INTERNAL CHECK for
about 10 seconds and go to the main menu.
5. Press the blue arrow once ( ) to position the
cursor in front of ON and press . The
display shown in the figure will appear.
6. Confirm the START OPERATION by pressing
.
The appliance is now in "ON mode". If there is a
heat demand, the appliance will run through the
heating cycle
(9.3 "The appliance's heating
cycle") .
If the heating cycle is not run, there is no heat
demand; if this is the case, Tset will probably need
to be set
(11.4 "Setting the water temperature") .
9.3 The appliance's heating cycle
The appliance's heating cycle is activated as soon as
the measured water temperature (T
net
) falls below the
threshold value (T
set
). This threshold value depends
on the currently selected appliance operating mode.
For example, if the appliance is in "OFF mode" (frost
protection), then this value is 5°C. If the appliance is in
"ON mode", then this threshold value is selectable, for
example, 65°C.
The heating cycle runs in turn through the following
states:
1. HEAT DEMAND;
2. PRE-PURGE;
3. PRESSURE SWITCH;
4. PRE-GLOW;
5. IGNITION;
6. RUNNING;
7. POST-PURGE.
The complete cycle is explained in the following
example, which assumes the appliance is in the basic
mode ON.
Note
The same heating cycle applies to the other
operating modes.
INTERNAL CHECK
MENU
»OFF
^ ON
È WEEK PROGRAM
n min
0063
O I
IMD-0423 R0
a
a
»START OPERATION
^ CHANGE SETPOINT
È Tset=65ÉC
a