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

Page: 92 / 98

Maintenance
92 Instruction Manual DR-FC
12
s
The display will now show
INTERNAL CHECK
for about 10 seconds, and
will then go to the main menu.
7. Activate the “ON mode” by going through the following steps:
- Press once on the DOWN button (
L
) to position the cursor beside
ON
,
then press
E
. The display shown in Figure 12.5 appears.
- Confirm with
E
the option
START OPERATION
.
8. If there is no heat demand, increase T
set
. See paragraph ’8.4 Setting the
water temperature’ (take note of the original setting) and draw off some
water to create a heat demand.
9. Check whether the heating cycle runs correctly. See paragraph ’7.4 The
water heater’s heating cycle’ .
10. If you adjusted T
set
, return the setting to the original value. See paragraph
’8.4 Setting the water temperature’ .
11. Remove the cover on the top side of the water heater.
12. Check the supply and burner pressures and adjust these, where necessary.
See paragraph ’3.11 Checking the supply pressure and burner pressure’ .
13. Check that all components of the flue gas system are properly attached.
14. Check the pressure differential across the orifice plate of the pressure
switch. See Table 12.1 . If the pressure differential is too low, then the heat
exchanger should be cleaned. See paragraph ’12.5 Finalising
maintenance’ .
15. Test the operation of the expansion valve of the cold supply setup. The water
should spurt out.
16. Test the overflow operation of the T&P valve. The water should spurt out.
17. Check the drain pipes from the discharge points of any valves and remove
any lime buildup that may be present.
18. Drain the water heater. See paragraph ’4.3 Draining the water heater’ .
INTERNAL CHECK
Figure 12.3 Internal check
MENU
»OFF
^ ON
È WEEK PROGRAM
Figure 12.4 Main menu
»START OPERATION
^ CHANGE SETPOINT
È
Tset=65ÉC
Figure 12.5 Starting up
Table 12.1 Pressure switch differential
Water
heater Observed pressure differential across the pressure switch
(Pa)
DR-FC 25 > 635
DR-FC 30 > 885
DR-FC 45 > 885
DR-FC 60 > 1085