How To Troubleshoot A Bosch Tankless Water Heater

Bosch manufactures a line of tankless water heaters. A tankless water heater provides an endless supply of hot water and reduces energy costs. The heating element is covered under warranty for a period of five years. All other parts are covered under a one-year warranty. If the tankless water heater develops a problem, troubleshoot it before calling for service. Disconnect the power supply to the water heater before removing the cover.

Step 1

Inspect the water supply. Connect the supply line to the blue inlet on the water heater.

Step 2

Disconnect the power, remove the cover on the water heater and reset the high-temperature thermal cutout. Push the reset button in the center of the cutout. Reconnect the power.

Step 3

Remove the cover and check the flow switch. The switch activates when hot water is turned on. If the switch does not activate, call for service.

Step 4

Turn the power selector screw to "Hi" with a screwdriver. Open the cover and turn the screw counterclockwise to loosen it. Push the screw from the "Lo" position to "Hi." Turn the screw clockwise to tighten it.

Step 1

Inspect the plumbing for restrictions. Pipe joints should not be sealed with plumber's glue. This can reduce the flow of water.

Step 2

Open the service inlet valve. Turn counterclockwise to open fully.

Step 3

Turn the shutoff valve on the water supply line counterclockwise to open fully.

Step 1

Turn the shutoff and service inlet valves counterclockwise to turn on the water supply fully.

Step 2

Shut off the inlet isolation valve on the water heater. Turn the hot water faucet on in a nearby sink. If there is a steady stream of water, the cold water is flowing into the hot water lines. Call a plumber to repair the crossover between hot and cold water lines.

Step 3

Remove the aerators on household faucets and remove sediment clogging the aerators.