8.3
Accessing the bottom inspection trap
Have a lip gasket and a retainer ring on hand for the
inspection hatch.
1. Disconnect the mains supply.
2. Drain the DHW tank.
3. Open a hot water tap.
4. Open the valve on the safety unit.
5. Set the appliance to repair position
1
.
6. Check the extent of scaling in the tank and on the exchanger.
Keep the limescale on the walls of the tank: it provides effective
protection against corrosion and enhances the DHW tank’s
insulation.
Remove limescale deposits from the bottom of the tank.
Remove limescale deposits from the exchanger to guarantee its
performance.
7. Fit the unit together.
CAUTION
Each time it is opened, the lip retainer ring unit
must be replaced to guarantee tightness.
Place the gasket’s positioning tab towards the outside of
the DHW tank.
8. After reassembly, check the tightness of the lower flange.
The screws retaining the visit trap must be tightened to
6 N·m +1/-0. Use a torque wrench.
85°
1
C
00
31
9
0-B
8. Checking and maintenance
TWH 200E TWH 300E TWH 300EH
60
19/01/2015 - 300026515-001-05
