Bosch Appliances 2400E NG, 2400E LP manual Troubleshooting Display Cause Solution

Display

Cause

Solution

E1

Over-temperature detected by temperature

1. This water heater must be supplied with cold

sensor on hot water pipe.

water for domestic hot water only. Do not

(part# 8700400015)

recirculate water through this heater or supply with

preheated water.

2. Check that the hot water temperature sensor is

firmly attached to the horizontal section of the hot

water pipe.

3. Check red wire connections at hot water

temperature sensor. Clean terminals with an eraser.

If badly corroded, replace sensor and wire harness.

4. Swap hot water temperature sensor with the cold

water temperature sensor. If the heater produces

an E2 error, replace hot water temperaure sensor.

5. Clean inlet filter screen per chapter 5.2 and clear

any debris out of shower heads, faucet aerators and

whole house filters.

6. In areas where water has a high mineral content,

periodic descaling may necessary. See chapter 5.3

E2

Cold water temperature sensor fault.

1. Check blue wire connections at cold water

(part# 8700400015)

temperature sensor. Clean terminals with an eraser.

If badly corroded, replace sensor and wire harness.

2. Verify that the sensor is firmly attached to the

horizontal section of the cold water pipe.

3. Sensor will trip if it detects temperatures at or

below 36°F. Protect heater from freezing conditions

as any damage resulting from freezing is not

covered under warranty.

4. Swap cold water temperature sensor with the hot

water temperature sensor. If the heater produces an

A7 error, replace cold water temperature sensor.

E9

Temperature limiter (ECO) open circuit

1. This water heater must be supplied with cold

(should reset when cooler temperatures are

water for domestic hot water only. Do not

detected).

recirculate water through this heater or supply with

(part# 8707206204)

preheated water.

2. Disconnect power supply cord and check white

wire connections on ECO (top right of heat

exchanger). Clean terminals with an eraser. If badly

corroded, replace sensor and wire harness.

3. Verify that venting meets specifications outlined

in chapter 3.6. Long vent lengths, venting with more

than three elbows, blocked vent or combination

venting may cause this failure. Verify backdraft

flapper inside flue gas collector is not stuck shut.

4. Clean inlet filter screen per chapter 5.1 and clear

any debris out of shower heads, faucet aerators and

whole house filters.

5. In areas where water has a high mineral content,

periodic descaling may necessary. See chapter 5.3

for directions.

6. Unplug power supply cord to the water heater.

Open a hot water tap for several minutes to allow

cold water to pass through heat exchanger. Close

hot water tap and disconnect lead wires to ECO.

Using a multimeter, check continuity through ECO

38

6 720 608 263