A.O. Smith TWI 35-200, Installation, User And Service Manual

Page: 68 / 92

11.2 Preparation
Isolate the water heater from the mains before you start maintenance tasks.
11.3 Water-side maintenance
To do water side maintenance:
• Descale the tank (see 11.3.1)
• Clean the condensate drain (see 11.3.2)
11.3.1 Descale the tank
If necessary, use a descaling agent to remove the scale and contamination from the tank.
Contact A.O. Smith for advice on what descaling agent to use.
11.3.2 Clean the condensate drain
To clean the condensate drain:
1.
Place a tray or towels under the condensate drain to collect water leakage.
2. Remove the condense trap at the bottom of the condensate drain.
3. Empty the condense trap and clean it with water.
4. Make sure that there are no blockages in the condense trap.
5. Make sure that there are no blockages in the condensate drain.
6. Make sure that there are no blockages in the drain pipe.
7. Make sure that the slope of the drain pipe is correct; 5 mm/m.
8. Install the condense trap onto the condensate drain.
Fig. Condensate drain
1
1. Condense trap
11.4 Gas-side maintenance
Do gas side maintenance when the water heater does not operate correctly, the air
pressure differential is not correct and/or the CO
2
value is not correct.
To do gas side maintenance:
• Clean the burner (see 11.4.1)
• Clean the combustion chamber
68 Installation, Maintenance and Service part