A step-by-step guide on installing and using Noritz remote controller RC-7646M-2 to change the temperature, monitor water heating operation and troubleshoot the problem.
The controller's digital display shows the actual exiting temperature of hot water in F or the water flow in gallons. Also, there is an indicator that shows when the burner is ON and priority indicator, so when it is lit the hot water temperature can be set. The display will flash when you press the flow meter alarm set button. If there is a problem with the water heater an error code (11, 90, 99...) will appear. See the list of all error codes found on Noritz tankless.
Temperature setting buttons are found as the up and down arrows and they are used for setting the hot water temperature at the exit of the heat exchanger and water heater and flow meter alarm. Keep in mind that the brand new unit is factory set at 110 F.
The power button is used to turn the water heater ON or OFF and mute the sound (by holding it for five seconds).
Flow meter alarm set button triggers the alarm after the preselected volume of water, in gallons, is delivered by the Noritz tankless water heater.
The remote should be installed in an easily accessible location, and not exposed to the water, steam, and chemicals, or direct sunlight. It can be installed outdoors but in the waterproof box, since the unit is only water resistant, not waterproof.
Either you are using one or two Noritz water heaters (with the use of the Quick Connect Multi System) only one remote controller should be installed (to one unit).
Detailed instructions here.
Start by pressing the On/Off button. The display will show the pre-set temperature of 110 F so by using the up (increase) or down (decrease) arrow you select the temperature you want. The temperature you can select is between the minimum 98 F and maximum 140 F, while the recommended is between 120 F and 125 F. Temperatures above 125 F can scald so the display will flash for 10 seconds, so be aware if you have kids around.
When the water flow reaches the set level, the alarm will sound for ten seconds. Stop the water manually or it will continue running (the burner ON light is OFF). You can set the water flow from 10 gallons to the maximum 990 gallons, with the 5 and 10 intervals. This great feature can be used, for example, to indicate when a hot tub is full (if hot water is not used for another application).
As said, you can use the remote controller to troubleshoot the problems on a Noritz tankless water heater. If the problem occurs a numerical error code will flash, such as the priority light and ON/OFF button.