Navien pressure valve

[Kiisu]

We had Navien tankless water heater installed about a week ago. The pressure relief valve was installed away from the drain opening in the floor and the installed told us that it was ok beacuse there wouldn't be any water leaking from it anyway.
Well, there has been quite a bit of water coming from the pressure relief pipe, flooding the floor in that area.
My question is: Should the pressure relief valve leaking this often or was the pipe installed incorrectly away from the drain?
Thanks for your help!

[jadnashua]

What is your house water pressure? Do you have a pressure reduction valve? With a tankless, you don't normally need an expansion tank, but that could be an issue. A pressure relief valve is a safety device. Normal house pressure should not be high enough to trigger it. It could be defective. If your house water pressure is quite high, you should install a PRV. Note, water pressure can change quite a bit from daytime to night time, with late night/early morning hours possibly the worst. When is the valve opening?

[Kiisu]

The pipes haven't been installed correctly. I just went downstairs and the assembly just below the chassis has leaking seals. The main hot water feed from the heater is 2" pipe and goes into a reducer to match the house piping. Is that okay, or should that pipe be 2" until it reaches the place where all the various pipes branch out tot he rest of the house? Looks like a bad install to begin with, but I wonder about the thought process of the guy that put it in. I'll be complaining to the contractor to the someone else in here.

[SewerRatz]

The pipes haven't been installed correctly. I just went downstairs and the assembly just below the chassis has leaking seals. The main hot water feed from the heater is 2" pipe and goes into a reducer to match the house piping. Is that okay, or should that pipe be 2" until it reaches the place where all the various pipes branch out tot he rest of the house? Looks like a bad install to begin with, but I wonder about the thought process of the guy that put it in. I'll be complaining to the contractor to the someone else in here.

If you could post some pictures. That would be helpful to us all