With my Axis the only way I can get hot water is to have the pressure on my water pressure regulator set to 54 psi. Anything less and it doesn't heat!
Even then in order to get hot water in the kitchen or vice versa the bath is to turn on both the kitchen and bath faucets and let them both run for a few minutes. Only then will the water temp rise to the thermostat setting!
Seems silly to do it this way especially since these tankless heaters are suppose to save water!
Hope this helps!
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