Can i adjust a flow sensor on a instantaneous hot water service

Most instant-on tankless water heaters require at least 10 psi of water pressure to start the heating process. The flow of water determines how hot the water will be, within the heating range. An electric 110 volts heater will increase the water temperature about 25 degrees F. A gas water heater will increase the water temperature about 45 degrees F.
Too much flow will not allow the water time to heat. Too little flow will not allow the heating system to work. Each heater must have the outflow water flow adjusted for the best heating outcomes. The best way to find the ideal flow is to turn the hot water facet on and adjust it (open or close) until the water reaches the balance of producing hot water.

The elements are getting over heated then set temperature.You have a defective thermostat. The elements will continue to heat until they reach the set point of the thermostat. Try to lower the temp setting first. If that does not fix it, you'll need to repalce the thermostat, located very near the element, under the screwed cover on the side of the tank.------------- To know how this heater works, read as follows:---

Because electric tankless water heaters have to instantaneously raise the temperature of incoming water to a selected hot water temperature, they require very powerful heating elements. To power the heating elements of this 27,000 Watt model, you will need to upgrade the electrical service you were using for your storage tank water heater. The PowerStar AE125 will require a 240V, 200 Amp service. In addition you will need to install three 40 amp dedicated double pole breakers in your electrical box. In Canada, you will require one 120 Amp breaker.

The PowerStar AE125 electric tankless water heater incorporates a very sensitive flow sensor, and three heating elements. The heat from the electric elements is electronically modulated on the basis of the flow rate of the water entering the water heater, and the temperature rise that the water heater must achieve. Through its electronic modulation system, the AE125 maintains a very precise hot water temperature. As a safety precaution, each of the three heating modules is protected by an electro-mechanical thermal cut-out. This device will cut power to a particular module if the temperature gets too hot.

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This will help.Thanks.Helpmech.

take the cover off the 10 h unit light up the burner by turning on the tap turn the water flow tap on the front of unit (white knob) clock wise slowly feel hot water pipe coming out off unit when temp increases put cover back on check temp at sink if too hot turn knob anti clock wise

clean filter on the cold side coming in and clean or replace the aerator at the sink, rinnai works on water flow, common problem if your water hardness to high or if you have iron in your water

Sounds like a flow sensor may be bad. It may be registering flow when there is none and it sending signal to ignitor and gas solenoid that there is.

sounds likr thermostat {overheat}

Not sure but check the inlet water at the heater, the filter may be clog up a little that restrict the flow. Did u use the heater at all during the winter? If not, the heat exchanger may be clogged with built up in there. U need to descale it. Good luck. Chinhcu

I found a way to get warm water in the shower, but I'm not sure it qualifies as a solution. After trying everything else I thought that maybe when I was feathering the faucet in the shower toward the cold side so I would get warm water that at a certain point it blocked the flow on the hot water side enough so that the sensor in the hot water heater sensed there was no demand in the line and it shut the water heater off. To test this, I went to the kitchen and turned the kitchen sink faucet all the way to the hot side and then turned it on so that I got a small flow of water. I waited for the water to get hot to be sure the hot water heater was working. Once it was hot, I left it running to keep demand in the line and then I went to the shower and turned the faucet on. When the water got hot I started feathering the control towards the cold side and soon I had warm water. So I think I'm right in that the sensor in the hot water heater was shutting the water heater off when the demand in the shower was lowered to a certain point when I was trying to adjust the water temp in the shower.

So now I can get warm water, but it means I have to leave the hot water running at another fixture in the house to create a false demand in the system so the hot water heater doesn't shut down. Is there a way to adjust the senor in the hot water heater so that it will stay on when I'm using the shower only, so I don't have to waste water by running another faucet when I want to take a shower?

thre is a sensor thaat goes from the gas valve to the pilot that is called a themocouple change that and you will have no more problem

I see the same problem and now that I know it's a water temp sensor, I really don't have a problem. Living in Houston it get's so hot the cold water is hot coming through the pipes. I didn't have this error 24 until summer...