DORCHESTER DR-FC 120, Installation, Comissioning And Maintenance Instructions

Page: 86 / 100

Performing maintenance
84 Instruction manual DR-FC
15
s
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, then raise T
set
. Note the original setting. Draw
some hot water off to create heat demand.
9. Check whether the operating cycle runs correctly (2.3 "Water heater
operating cycle") .
10. If you have adjusted T
set
, return it to the original value (11.4 "Setting the
water temperature") .
11. Remove the cover on the top of the water heater.
12. Check the supply and burner pressures
(3.11 "Checking supply pressure,
CO
2
value and switching pressure") and adjust these where necessary.
13. Check that all components of the chimney flue system are properly attached.
14. Check the pressure differential across the pressure
switch (3.11.3 "Switching pressure measurement") and, if this is too low, the
heat exchanger should be cleaned (15.4.3 "Clean heat exchanger") .
15. Test the operation of the overflow valve of the protected cold supply setup.
The water should spurt out.
16. Check the drainage pipes from the discharge points of all valves and remove
any scale deposits that may be present.
17. Drain the water heater (see draining (6 "Draining") ).
15.3 Water-side
maintenance
15.3.1 Introduction
The following steps must be carried out on the water side:
1.
Descaling and cleaning the tank .
2. Clean condensation water discharge .
15.3.2 Descaling and cleaning the tank
Scale and lime build-up prevent effective conduction of the heat to the water.
Periodic cleaning and descaling prevents build-up of these deposits. This
increases the service life of the water heater, and also improves the heating
process.
Take the rate of scale formation into account when deciding on the service
interval. Scale formation depends on the local water composition, the water
consumption and the water temperature setting. A water temperature setting of
maximum 60°C is recommended for the prevention of excessive scale build-up.
To guarantee a good, watertight seal around the cleaning opening, replace the
gasket, washers, bolts and, if necessary, the lid with new parts before
reassembly (see the figure). A special set is obtainable from the
supplier/manufacturer.
To simplify descaling and cleaning of the tank, the water heater is equipped with
two cleaning openings.
MENU
»OFF
^ ON
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