Viessmann Vitopend 100-W Installation And Service Instructions For Contractors page 41

Repairs
(cont.)
E Heating water flow
F Heating water return
Check the connections on the DHW side
for scale build-up and the connections on
the heating water side for contamination.
Clean or replace the plate heat
exchanger if required.
Replacing the plate heat exchanger
1. Push stepper motor A slightly
upwards.
45°
G Cold water
H DHW
2. Turn stepper motor adaptor B with
stepper motor A anti-clockwise by
1/8 of a turn and remove.
3. Remove 2 screws C from the plate
heat exchanger and remove plate
heat exchanger D with gaskets.
Troubleshooting
41