If your hot water dispenser is not heating at all, some common issues could be: 1. Dispenser is unplugged or circuit breaker is tripped 2. Tank thermostat needs replacement 3. Heating element needs replacement 4. Overheat safety shutoff has been triggered 5. Internal wiring failure Consult the troubleshooting guide or contact InSinkErator customer service for further help diagnosing causes and remedies if your dispenser is not heating water.