I have a problem with this combi, the dhw temp cycles wildly to the extent that it is almost impossible to run a hot bath. From reading various threads and sites, I believe the cause could be a scaled up domestic heat exchanger as I live in a hard water area.
I plan to remove the heat exchanger to descale, probably using Fernox DS3, however the instructions specify
"It should not be used with thin gauge or badly corroded aluminium, zinc, galvanised steel"
I do not know what material the exchanger is made from, can anyone help?
Thanks Glenn