Bosch AquaStar 2400ES-NG - Answered Questions & Fixed issues

Bosch 1-866-642-3198; 800-642-3111Copy following links to narrow down cause for EA error code:http://waterheatertimer.org/pdf/Bosch_EA_error_code_troubleshooting.pdfhttp://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.htmlAqua star service bulletinshttp://www.bosch-climate.us/bosch-hot-water/aquastar-service-bulletins/ If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

if you have incorrect gas line size when it kicks on the lack of gas pressure to the unit will cause a wistling. make sure you have enough gas to the unit

Hi,
The unit is plugged up with mineral buildup from the water going through it... it will need to be cleaned internally....this is done by running an acid solution through it to clean out the mineral buildup...

Then it will work again...

heatman101

E2 is a cold water inlet temp sensor. Has your unit experienced any freezing conditions? If it senses below 36 degrees or above 90 degrees it will show this error. If its normal temp, and you still get this error...check your sensor. Its an 8(kohm) sensor. Make sure its not open. If it reads ok and your temp is not an issue, then you probably have a bad control board

E2 is a cold water inlet temp sensor. Has your unit experienced any freezing conditions? If it senses below 36 degrees or above 90 degrees it will show this error. If its normal temp, and you still get this error...check your sensor. Its an 8(kohm) sensor. Make sure its not open. If it reads ok and your temp is not an issue, then you probably have a bad control board

C7 is displayed when the primary fan (the one in the middle just under the copper heat exchanger) does not spin or the computer does not recognize that it is spinning. There is a plug on the back of the fan. Make sure it is plugged in all the way.This also happens when the computer gets damaged because the unit is plugged in to an extension cord, power surge or poorly adjusted combustion (most contractors lack the proper equipment to adjust the flame on high efficiency equipment). I have been to over 500 tankless water heater installations and found every one of them were not adjusted at all! It can also be a damaged fan caused by an improperly installed exhaust pipe.

Clean out pilot jet probably dirt blocked it John then try again

possibly needs descaling and or pump needs replacing

you must read your owner manual read the troubleshooting section, and if the problem persist, get the website with your supplier and connect via ONLINE chat with technical personal in order to Help you and fix it. God bless you

http://www.bosch-climate.us/files/201109162006340.GWH2400ES_English_10_2007.pdfsounds like the inlet water screen needs to be cleaned or the unit is scaled up with minerals. see attached link to manual

Check for crossover.Bad single-handle faucet cartridge causes cold water to enter hot pipe, so hot never arrives and tankless does not run consistAntlyhttp://waterheatertimer.org/Crossover.html If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

On this unit it requires cleaning of water inlet valve every 3 to 5 years and it may need a kit woth new o rings.

1) Live answer Feb 2013:http://waterheatertimer.org/pdf/Bosch_EA_error_code_troubleshooting.pdf2) Call Bosch1-866-642-31983) Call service technician.4) Fix any brand tankless water heater problem yourself, same day, for $350http://waterheatertimer.org/How-to-install-gas-water-heater.html If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Here is the troubleshooting guide for the A7 code:http://www.bosch-climate.us/files/201109161634300.TWH-G2-31_A7_error_code_troubleshooting.pdf

the A3 & E3 codes are for the back flow sensor on the heater. Could be disconnected or a bad sensor. Call bosch tech support and they will help you with this.

Before calling service technician, copy following links for troubleshoot resources:http://waterheatertimer.org/pdf/Bosch_E9_troubleshooting.pdfhttp://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.htmlYou should delime water heater once per year to prevent many common error codes.http://waterheatertimer.org/pdf/Delime-tankless-water-heater.pdf If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Code EL does not show on typical Bosch error code list.Maybe you have E1 ?? Or Bosch has some other error codes not listed.http://waterheatertimer.org/pdf/Bosch_E1_troubleshooting.pdfhttp://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.htmlhttp://www.bosch-climate.us/support-center/technical-support/ If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Does it happen to any other fixture? If not, it's most likely your shower valve and not heater.

it must not be on properly or not tightened properly

Model????? The 635Es, 250SX and 2400E are same. The 2400ES and 2700ES are World 2 heaters. Any error codes as I can't imagine this problem w/o codes. Flow initiated but you have spark. Is there any ignition? If so flame rod may be bad and not reporting ignition. Igniter sets on some early 2400/2700 have proved to be bad. Water pressure has zero to do with this. If you have an EC or EA code you have gas problems (meter, line size/length or gas valve). Also if 3005 or 3007 Software you can pull the last 5-10 error codes from Controller.
You need to call Bosch and get an RSA out there. This is a gas appliance that if you screw up can destroy your house. FYI any water in the gas valve condemns it. It will not dry out and work correctly. Is the fan running at ignition and/or purge? Any Controller errors require replacement. You have 2 years on parts warranty from installation date so don't screw around trying to DIY. Warranty Labor is not covered.
Flue obstruction? If you used the AQ3 installation Kit you have the wrong termination box to prevent freeze up and/or water penetration You need the Z-Vent drop nosed termination. Look for a fine tan dust in the fan intake (brown plastic) the intake throat or in passageway to the gas valve. Call Bosch unless you're a Gas Tech this is beyond you.