I have a 2020 Reflection 29RS that will not push hot water to the fixtures on city connection or pump from tank. Water is cold at fixtures from both sides (hot and cold). HWH is plenty warm with hot water coming from pressure relief valve. I have researched extensively and ensured outdoor shower is off, replaced the hot water heater check valve with brass, and still no change. My last resort is to replace the hot water heater bypass valve (red on Nautilus P1) in case it is not functioning and remaining in bypass mode.

Anything else I should be checking? Thanks.