Navien NHB-055 wont go above 102 deg

[rasortown]

Hello, I have a 1-year-old Navien NHB-055 Tankless for hydronic floor heating only, that won't go above 102 deg on the outgoing water, for some reason they installed the "outdoor temperature sensor" inside so in my opinion the unit always thinks it is 70* out and keeps the water at a low temp. Everything I am reading says your water should be between 120- 180 outgoing. Is there any way to override the temperature sensor? I tried unplugging it from the unit but it errors out. I am not even sure if I could run the sensor outside because of how far the unit is from an outside wall and how short the wire is. Or am I wrong about the sensor and something else is going on? Any advice would be super helpful. Thanks a lot


-Jared.

 

[Geofd]

Hello, I have a 1-year-old Navien NHB-055 Tankless for hydronic floor heating only, that won't go above 102 deg on the outgoing water, for some reason they installed the "outdoor temperature sensor" inside so in my opinion the unit always thinks it is 70* out and keeps the water at a low temp. Everything I am reading says your water should be between 120- 180 outgoing. Is there any way to override the temperature sensor? I tried unplugging it from the unit but it errors out. I am not even sure if I could run the sensor outside because of how far the unit is from an outside wall and how short the wire is. Or am I wrong about the sensor and something else is going on? Any advice would be super helpful. Thanks a lot


-Jared.

Is the water at your mixing valve 102 or is your boiler temp 102

 

[rasortown]

not sure what a mixing valve is but the outgoing water is gets up to 102 and levels out. here is my setup.

 

[Geofd]

The out going temp says 82° I think , you wouldnt want high temp water going out remember your just warming the floor it's not like heating the perimeter were the piping is exposed under a metal cover

 

[Rickyman]

Put an ice pack on the sensor or dunk it in ice water if it’s waterproof and see what happens

 

[rasortown]

I love that idea, but we had an Hvac guy come and he disabled the sensor until we can run it outside and set it to manual, he said 125 is a good temp unless it gets really cold( he also turned down my pressure apparently it was circulating way to fast) thanks a lot to all who responded.

 

[FishScreener]

The high efficiency Boilers look at the exit temp and return temp. if your not dropping enough heat through the loop, they will cut back on the burner. I guess the folks who programmed the control logic, think that means there is no demand. And, if you are feeding a modern heating loop which is properly designed, it probably works.

WE replaced a fifty year old, oil burner, which ran at 180-F with a modern, high efficiency propane unit. Which runs at 170-F for about ten minutes, and then starts cutting back because the hydronic system wasn’t designed, it was put together with fin pipe only under the windows. So, the exit temp drops to 115-F, with a return of about 110-F, and the building never gets warm.