Tankless Water Heater Noisy Pipes

Another common problem that can create noise in tankless water heaters is a dirty flow sensor which controls how much gas is sent to the unit.

Tankless water heater noisy pipes.

Another standard issue that causes loud noises in tankless water heaters is a dirty flow sensor. If you hear a weird groaning sound from the pipes or the tankless hot water heater when you flush the toilet that could be the culprit. Even though a toilet only uses cold water i have seen some toilets do this. Other sources of noise include blocked or inadequate ventilation or a defective or improperly set pressure valve.

Water vapor is a byproduct of combustion although in this case the vapor contains elements such as methane nitrogen and oxygen. Inside a condensing tankless water heater the combustion process superheats the water that enters your shower sink etc. Generally speaking there is a lower chance of hearing strange noises with a tankless water heater vs tank model. If the running water noise continues once the tank is filled you may want to call a professional plumber to investigate the situation for you.

Or you can try to run down the leak yourself by checking the following. The sensor controls the amount of gas sent to the unit. Good luck with your project. In that case you need to have a plumber install a check valve in the water line.

Although keep in mind that it is normal to hear water entering the tank when hot water is being drawn.