Viessmann Vitodens 100-W WB1B Installation And Service Instructions Manual page 45

Repairs
(cont.)
Checking or replacing the plate-type heat exchanger (gas
fired condensing combi boiler)
E Heating water flow
F Heating water return
1. Shut off and drain the boiler on the
heating water and the DHW side.
2. Flip down control unit.
3. Push the three-way valve drive A
slightly upwards.
G Cold water
H DHW
4. Turn the three-way valve B with
drive A 1/8 anticlockwise and
remove.
Troubleshooting
45