Rinnai Flush

[dennisgilman]

Howdy. I have a 3 year old Rinnai Tankless Heater. I do a yearly vinegar flush on the Tankless through the service connections as follows: Turn off heater. Inspect filter. Close CW/HT valves. Open service connections. Connect hoses. Start pump submerged in vinegar. Last year I got great flow out of the hot water service connection using a 1/5 HP Pump (picture attached). I tried today. I got no flow out of the same connection. I aborted and returned heater to service. Heat working fine. Does anyone have any ideas? Thanks.

 

[Twowaxhack]

Does the pump work ? If water will run through the heater then your cleaning solution should.

Make sure the service valves are actually opening.

 

[dennisgilman]

It does. I verified the service connection ball valves work. I tried to send vinegar through the cold water service connection, through the heat exchanger and out the hot water service connection. No joy. No vinegar.

 

[dennisgilman]

The pump works. Send a stream of water half way down my driveway.

 

[dennisgilman]

So I am obviously sending house water through but not with the pump. Do you thing I should hook up the hoses to the service connection and open both and crack open the house ball valve on both sides to make sure?

 

[dennisgilman]

I say that because I can't see the cold water service connection ball valve position