Understand the distinction
Water-heating systems differ in design and intended operation. A temperature or operating suggestion copied from another system may not apply. The equipment manual and qualified professional advice provide the relevant context for service and settings.
Put it in your home notes
Record the model, existing user instructions and any professional recommendation without opening the unit. Ask about the purpose and implications of a proposed change. This journal does not supply temperature prescriptions, plumbing work or gas-system adjustment instructions.