Bosch AquaStar 2400ES-NG - Page 2 - Answered Questions & Fixed issues

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

Before calling service technician, call Bosch. 800-642-3111
E7 is not shown as common error code.
Error codes are considered start-point for troubleshooting.

Open following links for general Bosch troubleshoot resources:
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html
Common error codes:
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/2400ESTechSupport/Troubleshooting/tabid/1295/Default.aspx
Service bulletins for reading how to fix tankless yourself:
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/2400ESTechSupport/ServiceBulletins/tabid/1300/Default.aspx

Before calling service technician who has service manual and can test which part has failed, open following links for troubleshooting resources including steps below and phone number for Bosch:
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/2400ETechSupport/Troubleshooting/tabid/1131/Default.aspx

Clean inlet filter
Check all faucets for clear pathway
This unit does not work with preheated water (solar assisted)
Incoming water above 70 degrees, avoid restricted faucets
Check that both temperature sensors are making contact and firmly mounted on respective cold and hot pipes.
Descale heat exchanger
http://www.boschhotwater.com/Portals/7/TechBulletins/TWH-G2-13_Descaling.pdf

Yes. Contact Bosch.
Error codes are considered start-point for troubleshoot.
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Tankless are complex electronic machines.
If on-site plumbers cannot figure out problem, then you need trained service technician with a service manual for your specific product, who can ohm-test the electronics.
Bosch will have a list of trained service technicians. And maybe Bosch has another step for fixing problem yourself.

Fix most tankless problems yourself, same day, for $330.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Before calling service technician, open following links for troubleshoot resources including common error codes, Bosch contact information, link to service manuals, and possible product manual
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/2400ESTechSupport/Troubleshooting/tabid/1295/Default.aspx

Call Bosch 800-642-3111
Multiple error codes can mean PC board failure.
AF might be A9, but not sure.
EA is 'no flame ionization detected with water flow'

1. Verify that all manual gas shut off valves are open.
   
2. Check gas type.
   
3. Reset error code and open a water tap to cycle the heater in an effort to purge air on new installations. Cycling hot water tap on and off multiple times may be necessary. If heater still faults with EA error code, have a licensed gas technician properly purge air out of the gas line leading to the water heater.
   
4. Check three wire connections to ignition group on the lower front of the heat exchanger are secure.
   
5. Check gas pressure.
   
6. Check venting specifications are met. Improper venting may cause premature failure of the flame sensor rod.
   
7. Check that the minimum power fan speed has been adjusted to the proper value.
   
8. Observe inside the viewing window of the heat exchanger when a hot water tap is opened. Sparking should be followed by a steady blue flame. If flame is unstable or yellow with proper gas pressure.

Open following link for Bosch troubleshooting resources:
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Bosch has a service bulletin that might apply to problem:
http://waterheatertimer.org/pdf/Bosch_Overcoming_fluctuating_temps.pdf
Links about crossover and low water pressure:
http://waterheatertimer.org/Crossover.html
http://waterheatertimer.org/Low-hot-water-pressure.html

Add a comment and say what you did to fix problem.

Before calling service technician, open following link for Bosch troubleshooting resources, including error codes, manual, Bosch contact info, and service bulletins.
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Error codes are starting point for troubleshoot.
e2 is cold water temperature sensor fault.
Bosch error code says: 1) Check connector on wires coming from top of water valve for a secure connection.
2) Sensor may trip if water temperature drops below freezing to protect heater from freezing conditions Any damage due to freezing conditions is not covered under warranty.

Another contributing cause can be temperature thermostat set very high and tankless sensor is going bad, and very cold incoming water, or combination of factors above.

Also read manual for advisories and required maintenance. Some units require water filter be cleaned monthly.

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

Look for the error code on heater. Go to: http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/2400ETechSupport/Troubleshooting/tabid/1131/Default.aspx

For technical support on your heater.

Before calling service technician, open following link for Bosch troubleshooting resources.
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Sample manual has troubleshoot section and yearly maintenance requirement.
http://waterheatertimer.org/pdf/Bosch-250SXO.pdf

Service bulletins for 250SXO
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/250SXOTechSupport/ServiceBulletins/tabid/573/Default.aspx

Tankless require yearly maintenance as outlined in manual.
No tankless manufacturer suggests do-it-yourself repairs on their product, in part for liability and danger to customers, but for long-term customer satisfaction.
Repairs and yearly maintenance will eliminate the $1-8 monthly energy savings expected from owning tankless.

Before calling service technician, open following link for troubleshooting resources including error codes, manual, links to bosch, phone number, :
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

A7 is outlet temperature sensor fault.
Temperature below freezing or above 210 degrees F

1) Check red wire connections at hot water temperature sensor. Clean terminals with an eraser. If badly corroded, replace sensor and wire harness. (See Fig. 63, page 46 in manual).
2) Sensor may trip if water temperature drops below freezing to protect heater from freezing conditions. Any damage due to freezing conditions is not covered under warranty.
3) Clean inlet filter screen and clear any debris out of shower heads, faucet aerators and whole house filters.
4) In areas where water has a high mineral content, periodic descaling may be necessary.

Before calling service technician, open following link to download typical manual, get Bosch contact information etc.
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Add a comment with your experience so others with same-similar problem can benefit.

Also take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

A lot of factors, internal and external, can cause this problem ranging from bad PC board to plumbing problem.

Since you have no error code, it could be plumbing,
http://waterheatertimer.org/pdf/No-Error-Code.pdf

Open following link for useful Bosch troubleshooting information including Bosch support and typical manual for 2700 gas tankless:
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

For folks with Rheem tankless:
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

Add a comment with your experience so others with same-similar problem can benefit.

Also take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

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.

See the distributor ,they should be able to supply the required regulator.
I have an earlier model Bosch tankless water heater. my instruction says mine can.
I would assume that yours should be also.
Good Luck.

1) BOSCH error code A7: Outlet temperature sensor fault (Temperature below freezing or above 210?F).
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/2400ESTechSupport/Troubleshooting/tabid/1295/Default.aspx
a. Check red wire connections at hot water temperature sensor. Clean terminals with an eraser. If badly corroded, replace sensor and wire harness. (See Fig. 63, page 46 in manual).
b. Sensor may trip if water temperature drops below freezing to protect heater from freezing conditions. Any damage due to freezing conditions is not covered under warranty.
c. Clean inlet filter screen and clear any debris out of shower heads, faucet aerators and whole house filters.
d. In areas where water has a high mineral content, periodic descaling (de-liming) may be necessary.

2) Bosch has online tech support form:
http://forms.boschhotwater.com/Home/BoschTechSupportForm/tabid/614/Default.aspx

3) Bosch problems at Fixya:
http://www.fixya.com/support/p949576-bosch_1600h_lp_liquid_propane_aquastar_a/solutions

4) Read manual cover to cover and make sure maintenance is scheduled.
For example de-liming is recommended each year.
Utube search de-lime tankless water heater

Add a comment for more free help.
Also take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

Freezing water inside pipes can damage your water heater.
you should lag the pipes and if not fitted you should fit a cover to the pipework.
Is the unit outside? if so here is a link to a manual with some info on Bosch water heaters
http://www.boschhotwater.com/Portals/7/TechManuals/PipeCover_10.2009.pdf

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

The gas flame igniter is not working properly.

Go to the link below and type in your model or select it and the instructions take you through the gas pressures and so on.

I have had the same problem. I took the cover off, and put an electric heater (1400 watts, with built in fan), on a stand 1 1/2 feet away, blowing at the upper half of the Bosch. When you take the cover off, you will see a rectangular copper shaped thing - that is the heat exchanger. The copper water lines run through it and freeze from the cold air coming back down through the flue.
Whenever the temperature is going to be 15 degrees or less overnight, I turn the electric heater on. In fact, I leave it set up, on a stand, with the Bosch cover off, all the time... just in case.
This is really a poor design. With the money we've invested.....what a joke. Oh, and I do have the anti-freeze heat trace kit installed as well. Hahahaha, what a joke.

Hi,

1. Check for flue gas leakage around the top and bottom seals of heat exchanger as well as the viewing window. Look for any noticeable burn marks or warping of the gaskets. If a leak is detected, seals will need replacing.
   
2. Verify that venting meets specifications outlined in chapter 3.6 of the installation manual. Long vent lengths, incorrect venting material, 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.
   
3. Check flue gas limiter wire connectors for tightness. Clean with pencil eraser if any corrosion is evident.
   
4. Trace wires from flue gas limiter to black connector. Verify the connection is tight.
   
5. If limiter is tripped due to overheating, it must cool down before error will clear on the control board.

If your connections are good and the CO2 level has not been an issue in the past you can start getting into replacing parts. Bosch technical help water line may help a little but they will want all of the make, model, serial number business as well as owner name before helping, at all. If your unit can be repaired a good technician is the answer.

Let me know,if needed further assistance.

Hope i helped you.

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