Is something wrong with my tankless water heater?

Question

This water heater was in the house when we bought it. I find it very annoying. When I finally get some hot water to the shower, it lasts for 1 minute, goes cold for 2 minutes, hot again for another minute, etc. I can stand in the shower for 10 minutes an have 3 minutes of hot water total. Today I when it went cold the 4th time the water never did get hot again (I let it run about 10 minutes to see what would happen). And there is no way I would be able to fill a bathtub with hot water to soak in. That's a lot of water waste and high water bills (I live in southern California). Any suggestions?

Answer 1

Broken on-demand flow meter, gas valve, or control board. Call a tech or get a new unit.

Answer 2

Still descale the Instant flow water heater.



Clean or not, it actually the water pressure switch that determines when to turn up the heat or take it away in a tank less system. If this switch malfunctions, it could not set the circuit either gas or electric to on to heat the water. Consider that pressure switch like an instant thermostat switch, heat on or heat off. The lime / scale buildup could cause it to stick in the off position, and the water flow could free some particles of the scaling to turn on, then some build up and cause it to turn off. Now yours could be completely electric and not use gas.



Either way, you might have to go without hot water for a while until it can get descaled. If it has been descaled, my next best educated guess will be the temperature sensing part of the thermostat. This part is either attached to the coils by it being screwed into a port, or mounted to a part on the coil.



Lastly, it could be the main logic board that went bad.







Edit:

More... I seen 30 AMP instant flow water heaters which produced scalding hot water.

Answer 3

First off, has it been descaled recently. Tankless water heaters are supposed to be flush with vinegar every year to 18 months. Scale buildup could be causing it to disfunction. You can find videos on YouTube with instructions for descaling a heater. After you descale, if it still doesn't work right, get a tech to check it out. Tankless water heaters, when properly maintained, should last 20-30 years.

Answer 4

you did not specify how large it was (obviously.)



many idiots have these put in not realizing the temp rise on many of the cheaper ones is only 40-45 degrees, which is about 90-100 degree water, not very hot.

Answer 5

if its not flashing an error code it needs to be cleaned