Navien Dhw Mode. Here are some common navien tankless water heater. I do not have the remote but the led on the unit shows supply temps which oscillate.
![Dhw mode and priority operation, Dhw priority override tekmar 422 Universal Reset Module User](https://i2.wp.com/www.manualsdir.com/manuals/594774/24/tekmar-422-universal-reset-module-page24.png)
I've got a navien combi 240a which is giving inconsistent and low domestic hot water out. The heating system works however. I did have two consistent.