I'm about to move and replumb some of our equipment and was convinced I should put a bypass on the heatpump as it is only used here 2 months a year at most. But on speaking with Sue at heat siphon (the companies very friendly and knowledgeable tech person) said a bypass is not necessary as they use titanium and full flow through design so chemicals have no effect on the unit. She said I could put one in but totally up to me.
So I'm leaning to leaving it out (heat pump hasn't had one for 10 years and running fine).
What do you think?