water sanitizing issue

[MCM]

We (newbies) just bought a used 2021 Omni SV34, and are onboarding ourselves. In trying to sanitize the freshwater system, instructions all say to by-pass the (Girard) tankless water heater, and the by-pass valves should be behind the back of the heater. That puts them under the kitchen sink and behind a fixed partition that's at the back of the under-sink cabinet. If they're there, they're neither visible without a small mirror, nor accessible at all. How can I visualize and get at the by-pass valves to complete the sanitization? We'd be grateful for any suggestions! Thanks.
We'd also like to note that you Forum contributors take this work very seriously--THANK YOU!
MCM

[Mr Sunshine]

Welcome MCM. You asked a good question, but it would be better seen in a new thread.

Have you registered your rig with the Thor website and accessed your schematics?

[Pete'sMH]

I don’t have your model or your water heater. But to be effective the bypass valves need to be immediately adjacent to the water heater. Is the panel under the sink attached with screws? My Thor required removal of four screws.