Basically this technology helps to test on the gas valve a dual btu valve of your water heater.
Tankless water heater flow sensor not working.
Check the gas burner and does the flame rod generate sparks when the unit is turned on.
Make sure that the shut off valve is not closed.
Depending on your tankless water heater s capacity too many simultaneous hot water applications such as multiple showers running can overload your water heater.
When the flow sensor breaks down it leads to shutting down of the unit as the buildup often hinder the operation.
Rinnai tankless gas water heaters need a demand of at least 0 4 to 0 6 gallons per minute of water flow through the hot side to ignite and 0 26 gallons per minute to stay in operation.
In europe and other regions pressure pump showers with flow sensor based utility metering technology are widely used.
Poor flow sensor leads to little or no supply of hot water.
I recommend that you should utilize the high low sensor when the wci pressure has incorrectly read inches of the water column though you have set the mode switch.
The first things you should check are the correct supply of electricity water and gas to the water heater.
If not check this article that deals with the ignition failure problem.
If you are new then use a filter inside of the water flow pipe for stopping the problem from the beginning.
Your water heater may struggle to supply the hot water needed or shut down altogether if it becomes overloaded.
Flow sensors are also used in tankless water heaters.
A flow sensor performs the same function but provides the added benefit of measuring the rate of water flow.
You see every tankless water heater has a minimum flow rate which is the minimum amount of water measured in gallons that the tankless unit needs flowing through it every minute gpm to produce hot water.
If you have an older tankless water heater 10 years old the problem is most likely that the minimum flow rate is too high.
If there is a low flow from the heater the first thing to check would be the input filter.
Flow sensor one of the major problems common to navien tankless water heaters is a quick erosion of the flow sensor.
The pressure pump creates pressure for the shower when water.
To solve the issue first check the device plug related problem properly if it does not work then changing control board will be a better solution.
Turn off the cold supply relieve the hot pressure and remove the filter to check for debris.
Clean or replace the filter and then check the flow again.