Water does not get hot.
Light not on.
Odor in water.
Resetting High Limit Switch
Occasionally, the high temperature limit shut off device may trip the
reset. This occurs when water temperature exceeds 190 °F. The shut off
device may also trigger from a power outage or electrical storm.
To reach the thermostat:
▶ Disconnect power cord (or shut off circuit breaker - model ES8) and
remove the front cover.
▶ Firmly press reset button (Fig. 13, [B]) with the tip of a ball point pen
or similar object.
A click indicates the reset was tripped.
▶ Reconnect power.
IMPORTANT: Check the operation of the thermostat:
▶ Turn temperature dial from high to low.
If the red light does not go off on low setting:
▶ Turn off power supply and call a service person to replace the
If the red light does go off the thermostat is working well:
Make sure the power supply is on and working.
If light does not come on, check that the high limit reset button is pushed in;
follow steps in section 7.1.
If the indicator light works properly but temperature does not get hot at the tap, test for a plumbing crossover;
shut off cold supply to heater and open hot water tap. There should be no water flowing. Any continued flow
indicates a crossover which will effect the temperature and will need to be corrected.
Call a qualified service technician to test the resistance of the heating element (8-10 ohms). Heating element
should be replaced if readings are outside these values.
If the light does not come on, but water gets hot, check for faulty bulb.
Check high limit reset button;
follow steps in section 7.1;
Brown or rusty water indicates a "spent" anode rod and possible deterioration of the tank body.
Inspect the tank for leaks.
Check anode rod (see section on changing the anode rod).
Smelly water could be due to an unusual reaction between local water and the heater's anode rod. Check anode
rod (see section on changing the anode rod).
Failure to do so may result in damage to the tank and leaks.
Check water fittings and T & P fitting on top of tank.
Remove front cover and inspect heating element gasket.
If tank is leaking call Bosch Water Heating for warranty claim if still within warranty period.
Check anode rod (see section on changing the anode rod)
▶ Place dial setting to desired setting.
A lower setting is more economical and reduces the risk
▶ Replace cover plate.
Call a technician if the high limit needs to be reset
Troubleshooting | 11
6 720 801 072 (2013/05)