20 Most Recent Bosch AquaStar 2400ES-NG Questions & Answers


Bosch 1-866-642-3198; 800-642-3111
Copy following links to narrow down cause for EA error code:
http://waterheatertimer.org/pdf/Bosch_EA_error_code_troubleshooting.pdf
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Aqua star service bulletins
http://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

Bosch AquaStar... | Answered on Mar 23, 2018


This should run two showers at once with no problem. If you have a shut off valve on the cold side of the heater, try closing about halfway. This will slow the water flow and the water will have more time to heat up as it pases through the tank. If you dont have a shut off valve, just cut back the hot water valve on your shower and do not use any cold water. If it gets too hot then turn on a little cold water. The object is to slow the speed of the water going through the tank. Tankless heater take a little getting use to but they work great when you know how to treat them. On my shower I turn the hot all the way on until it gets hot and then add a little cold water to bring the temp down. You may have too much water going through too fast to be able to heat it up to what you need. Try this and see how it works.

Bosch AquaStar... | Answered on Dec 18, 2017


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

Bosch AquaStar... | Answered on May 16, 2016


Check for crossover.
Bad single-handle faucet cartridge causes cold water to enter hot pipe, so hot never arrives and tankless does not run consistAntly
http://waterheatertimer.org/Crossover.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Bosch AquaStar... | Answered on Dec 01, 2015


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

Bosch AquaStar... | Answered on Dec 16, 2014


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.

Bosch AquaStar... | Answered on Oct 30, 2014


it sounds more like the gas valve, you can taje the numbers off of it call or e-mail the compant and buy a new one,,, the thermal coupling keeps the piliot lit but i don't get it RECONDITIONED, I have been doing plumbing for 34 years now and to get a water heater thats reconditioned it would probobly be cheaper to buy a new water heater with this kind of problem good luck

Bosch AquaStar... | Answered on Sep 10, 2014


One of the problems with these has been that you must be using at least 1/2 gallon per minute for the burners to ignite. In the summer when the incoming water is already warm, we tend to not use enough hot water to keep it lit. Try turning on the hot water faucet in the sink and 'wasting' some hot water during the shower. If that fixes the problem you can find some other adjustments on the Aquastar website to help lower the temp some.

Bosch AquaStar... | Answered on Jun 24, 2014


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

Bosch AquaStar... | Answered on May 06, 2014


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

Bosch AquaStar... | Answered on May 06, 2014


Sounds like the water flow sensor and servo, may just need cleaning, get it checked out by a Bosch agent

Bosch AquaStar... | Answered on Apr 25, 2014


BOSH AQ 250 On demand propane water heater ran out of propane, got gas now, but get EC flashing on the display and the unit won't fire? Lost manual, any suggestions. Thanks, Jim

Bosch AquaStar... | Answered on Nov 10, 2013


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.

Bosch AquaStar... | Answered on Oct 17, 2013


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

Bosch AquaStar... | Answered on Oct 12, 2013

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