This was a requested video by two tankless company's Navien and Rinnai.
Tech. support have been getting hundreds of calls. pretraining to units not working, very bad hot water pressure or no water at all, broken water service valves, leak in heat exchangers etc.
It very important to use a licensed plumber trained to the highest level of the tankless company you have installed in your home. If you had the tankless installed use the plumber who installed it. If it's a new home call or look upon the company's website for a qualified installer, servicer. I know everybody wants to save money, but this will cost you more immediately or on the long run.

I decided to add a second part to this video because I felt it was important to show the final steps to get the tankless back up and running. This happens to be a Rinnai RUR199IP, but the procedure is the same for any other tankless condensing and non-condensing interior or exterior. The only tankless this would not be used for is the Navien NPE series A2 with the internal pump. (See my last video)
The tools you will need is a pump with hoses Flow Air is the one we use.
Vinegar or some sort of tankless cleaner.
5 gallon bucket
rags
The tankless tool www.thetanklesstool.com
5/8" socket and ratchet
brushes and gun swabs.
Please, like, subscribe and share this video,
I hope you enjoy this video,
Mike

PLEASE USE A LICENSED PLUMBER TRAINED IN THE HIGHEST-LEVEL TRAINING OF YOUR TANKLESS COMPANY. FOLLOW ALL LOCAL AND NATIONAL PLUMBING AND GAS CODES AND TO FILE A PERMIT WITH YOUR LOCAL BUILDING DEPARTMENT.