If the red light on your new Bosch water heater has gone off, it indicates that the unit is functioning normally and heating water as expected.
When the red light on your Bosch water heater goes off, it usually indicates the unit has reached its set temperature. But if you’re experiencing issues with hot water or the light behaves unexpectedly, troubleshooting is needed. This guide covers all potential causes and solutions.
Why the Red Light Turns Off Normally
The indicator light on Bosch water heaters serves as a visual temperature gauge:
- Light ON = Heating in progress
- Light OFF = Desired temperature reached
This is normal operation. The light cycles on/off as the unit maintains temperature. No action needed unless you’re experiencing hot water problems.
When the Red Light Off Indicates Problems
No Hot Water Despite Light Being Off
If the light is off but you’re not getting hot water:
- Check power supply – ensure unit is plugged in and outlet works
- Verify thermostat setting – adjust clockwise to increase temperature
- Test with another appliance to confirm outlet functionality
Light Won’t Turn On At All
If the indicator light doesn’t illuminate when adjusting the thermostat:
| Issue | Solution |
|---|---|
| Power switch off | Turn switch to ON (I) position |
| Tripped reset button | Press reset button on thermostat |
| Faulty thermostat | Replace thermostat if reset doesn’t work |
| Failed heating element | Replace element if thermostat works but no heat |
Advanced Troubleshooting Steps
Checking the Thermostat
For GL8 ProTi models:
- Unplug the heater and remove front cover
- Locate small square opening on thermostat
- Press reset button with pen or small screwdriver
- If frequent resets needed, replace thermostat
Water Leak Diagnosis
Different leak locations indicate different problems:
- Fitting connections: Replace corroded fittings
- Pressure relief valve: Check for backflow prevention devices
- Behind front cover: Replace element gasket
- Other tank locations: Requires tank replacement
Preventive Maintenance Tips
Anode Rod Inspection
The magnesium anode rod protects your tank from corrosion. Quality replacement rods can extend your heater’s life. Inspect annually and replace when:
- Water becomes discolored
- Unusual odors develop
- Rod is less than 1/2″ thick
Pressure Regulation
Ensure your plumbing system:
- Has no check valves before the heater
- Uses proper pressure/temperature relief valve (150 psi max)
- Maintains building water pressure below 150 psi
When to Call a Professional
Contact a licensed technician if you encounter:
- Persistent leaks from tank body
- Frequent pressure relief valve discharges
- Electrical issues beyond basic troubleshooting
- Need for specialized HVAC tools for repairs
For complex installations or if uncomfortable with electrical/plumbing work, professional service ensures safety and proper operation. Bosch recommends contacting original installers or licensed technicians for advanced issues.
