1. The portable tankless water heater requires a minimum of about .75 GPM and a minimum of about 20 PSI to activate and approximately 25 sustained PSI to continue to operate. Consider your water source: Are you using a pump to draw water from a source? Be sure the pump you are using provides adequate sustained water pressure to activate and keep the water heater running.

2. Check that your batteries are fresh and aligned with the proper polarity (+/-): flat negative of battery toward the spring side of the battery compartment.