Rinnai RUR199iN flushing

[goozoo]

Hey all

We had our contractors install a Rannai tankless water heater (RUR199iN) which has been blinking SS for a few days. It has a recirc limb that brings hot water to our master bath which is the furthest point away from the unit. It looks like the tank needs to be serviced/flushed. I have watched some tutorials and it seems like a pretty straightforward process with a Flow-Aid Tankless Flush KIT. The only question I have is can anyone tell me which valve (red or black circle) should I connect the hose IN to my unit for flushing? Im assuming the valve circled in black but wanted to see what you guys thought.

Thanks
Omeed

 

[Twowaxhack]

Close the one circled in red and connect the hose to the one circled in black.

Also close the lower valve. The only valve you want open in your picture is the one circled in black with a hose attached. Same with the hot side of the heater.

 

[goozoo]

Close the one circled in red and connect the hose to the one circled in black.

Also close the lower valve. The only valve you want open in your picture is the one circled in black with a hose attached. Same with the hot side of the heater.

Awesome. Thanks for your help.

Omeed