Reset bosch error code

SOURCE: Keep getting error codes and have to reset too often

This paticular problem your having is specific to the jumper in the heater. The jumper is for condensing heaters. Your heater does not have the specific wiring or computer for condensing. So they added a jumper in the wiring. It is failed or failing. It should ohm out at about 120ohms. sometimes its just a loose connection. Check this out, and called 1-800-642-3111, they have been very busy, but leave them a message and they will call you back.

SOURCE: A2 error on Bosch tankless water heater

1. Check continuity of the flue gas limiter (see Fig. 63, page 46 of manual). Go to steps two and three to determine air box temperature sensor fault and replace it.
2. Check for flue gas leakage around the top and bottom seals of heat exchanger as well as the viewing window.
3. Check that venting is within specifications (see Section 3.3 of manual). Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure.
4. Check that flue gas limiter connector and spade connections are secure.
5. Unplug heater and check the two main plug connections inside the control board.

SOURCE: BOSCH AQUASTAR 2400ES NATURAL GAS TANKLESS HOT WATER HEATER

Q. FA - Gas leakage error, gas valve circuit not closing properly
A.

1. Disconnect power supply cord and check wire connections on gas valve and the two connectors on the control board.
   
2. Flow water out of a hot water tap above the minimum activation point of .8GPM. Measure voltage at the gas valve wire connector. The connector should measure 24VDC between the left pair of wires and 24VDC between the right pair of wires when the unit is operating. If voltage is not correct, contact Bosch Water Heating for further instruction.
   
3. Gas valve may be defective, contact Bosch Water Heating for further instruction.

SOURCE: i AM GETTING AN A2 ERROR CODE

hi ill try to help the fault is in the overheat cutoff fuse its the white overheat wire fuse that wraps around the heat exchanger disconnect the plug connector between the fuse wire and the control unit ! using a multimeter check the resistance through the fuse to see if its bad !if its bad check to find the cause ie .a leakage of flue gasses on the heatexchanger also check the black rubber seals located at the top and bottom of the heat exchanger also inspect the seal around the viewing window on the heat exchanger then call tec support and report leakage areas also for fuse replacement the only number for tec support i can find is 08006423111 i do hope this helps

SOURCE: Bosch Tankless water heater. model AQ 250 SX

Error codes F1 and F2 do not show among common error codes.
Call Bosch 1-800-642-3111

Before calling service technician, open following links for Bosch troubleshoot resources:
Error codes are considered start-point for troubleshoot.
Multiple error codes can indicate PC board failure.
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/250SXOTechSupport/Troubleshoot/tabid/569/Default.aspx
http://forms.boschhotwater.com/Home/BoschTechSupportForm/tabid/614/Default.aspx
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/250SXOTechSupport/ServiceBulletins/tabid/573/Default.aspx