I need a replacement remote control for Rinnai 406tr

trouble shooting section will help https://sahotwater.com.au/specifications/Rinnai/Service%20manual/smV1616W_V2018W_V2020W.pdf

[PDF]Operation / Installation Manual - Rinnai

https://www.rinnai.us/.../V_Series_Indoor_25xx_U...

Rinnai America Corp.temperature (shown on the digital remote control) the gas burner will ... Without the connection of a remote controller(s), the Rinnai Water Heater is preset to.

PDF]Tankless Water Heater Service Manual - Rinnai

https://www.rinnai.us/.../100000098_Rev_B.pdf

Rinnai America Corp.Indicates condensing water heater models. ... Rinnai Water Heater Service Manual. 2 ..... Digital manometer or U tube type manometer with 14 inch water column (W.C.) scale, a hose and two .... will flash on the display of the remote controller.

A registered gas installer can obtain parts through Rinnai stockists and convert most heaters.

Here is a link for one on ebay. Looks like you need to go to the Rinnai web site and contact one of their authorized dealers/service providers in your area. Doesn't look good in cutting out the middleman on this one. Hope this helps you out.

http://cgi.ebay.com/Rinnai-Digital-Remote-Water-Heater-Control-BC-45-4US_W0QQitemZ400075236102QQcategoryZ3191QQcmdZViewItemQQ_trksidZp4340.m263QQ_trkparmsZalgo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D10%26pmod%3D250738075209%26ps%3D63%26clkid%3D5773450796685891657

The manual says:
http://www.coinwash.com/temp/rinnai.pdf

"For the name of the Authorized Distributor or Installer nearest you, please contact your local HVAC dealer or gas service technician, visit the Rinnai website (www.rinnai.us), call Rinnai at1-800-621-9419 or write to Rinnai, 103 International Drive, Peachtree City, Georgia 30269"

Manual says that the remote is for setting temperature.
When you turn on hot water spigot, tankless water heater will heat the water to the set point temperature.
If water heater is not set up to use remote, then tankless unit will heat to 140 degrees F.
"With the MCC-45-4US remote control installed the water temperature is adjustable from 96
to 180°F. The water temperature cannot be set to a temperature other than 140°F
without the use of the MCC-45-4US remote control unit. If you require a temperature
other than 140°F you must install the MCC-45-4US remote control unit."

"Error messages are displayed on the remote control units, simplifying service calls."

Page 9 of manual shows hot to set temperature using remote.
Water taps must be shut off to set temperature.
Circulating pump must be turned off.
"Simply press the H or C button until desired temperature is displayed"
"green in-use indicator will display"

If your unit is not working, the manual says to contact local plumber.
Fixya has specialists who will talk to you by phone about your problem for a fee.

Centre tap of the rinnai will turn off hot water supply only.
Easiest way is to turn off your mains water supply. This will isolate both hot and cold, no need to turn off anything else

Try National Energy they are on line they sell spares they may be able to help .

Check with Rinnai to see if the old remotes are compatible with the new heater. Might mean upgrading the remotes too but the wires should be OK. Double check that he has actually connected the wires to the heater. Rinnai in Australia recentyl changed the connection point for the wiring. I can help further with this if this is the issue (not sure where you are!)

if you mean additional remotes then go to rinnai.com and enter your model number. go to owners manual and it gives step by step instructions

I had a similar problem, the water flow control device was bad.
If you disconnect Connector B2 and the unit will start, then that will confirm the problem. Rinnai has a new improved part for replacement.