A.O. Smith 120 through 250 Series - Manual (Page 86)

Performing maintenance
86 Instruction manual BFC
15
s
6. 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
will then go to the main menu.
7. Activate "ON mode" by going through the following steps:
- Press once on the blue arrow ( ) to position the cursor beside ON,
then press
.
- Confirm the selection START OPERATION with .
8. If there is no heat demand, increase Tset (11.4 "Setting the water
temperature") . Note the original setting. Draw some hot water off to create
heat demand.
9. Check whether the heating cycle runs correctly (9.3 "The appliance's
heating cycle") .
10. If you have adjusted T
set
, return it to the desired value (11.4 "Setting the
water temperature") .
11. Remove the plastic cover on the top of the appliance.
12. Check the supply and burner pressure
(3.11 "Checking the supply pressure
and burner pressure") , and adjust them if necessary.
13. Check that all components of the chimney flue system are properly attached.
14. Check the pressure differential across the orifice plate of the pressure switch
(see the table). If the pressure difference is too low, the heat exchanger must
be cleaned
(15.4.4 "Cleaning the heat exchanger") .
Pressure switch pressure differential
INTERNAL CHECK
MENU
»OFF
^ ON
È WEEK PROGRAM
Appliance Observed pressure differential across the pressure switch
(Pa)
BFC 28 > 635
BFC 30 > 885
BFC 50 > 885
BFC 60 > 1085
n min
0063
O I
IMD-0423 R0