E4 code on a bosch ghw 715 control unit - Bosch ProTankless GWH 715 ES LP Tankless Water Heater, Propane

https://www.fixya.com/support/t13643459-a2_af_error_codes

WOW!!!
Great answer by Steve (I know Steve Spam...real name Richard). Lot of time on his hands (37000 answers).

Can we get real professionals answering questions.

Thank you Richard...let's just call you Dick for short.

Check for obstruction in your watervalve. It has a flow meter, that needs to spin freely. Remove the watervalve and blow through it, you should hear it spin.
Also make sure you dont have an error code showing. Hold down your reset button for 5 seconds to reset an error code and get back to your set temp.

Is this a water heater? Bosch site might have manual. And service bulletins, but I have not heard of that model.
http://www.bosch-climate.us/Bosch-Hot-Water/
Call local service technician who is qualified to work on tankless computer that heats water.
You can fix any brand tankless computer, any problem, same day, yourself by replacing 1 part: the whole thing:
http://waterheatertimer.org/How-to-install-gas-water-heater.html
Gene
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If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Are you looking for sell sheet pdf, or install-care manual, or service manual.
Search: GWH 715 ES manual .pdf
Adding .pdf to search parameter helps locate manuals.

Sell sheet with venting overview, technical and product specs:
http://www.globaltowne.com/manuals/sell_sheets/715-800SellSheetFINAL.pdf

Manual for ES high altitude, with installation, error codes and troubleshoot:
http://www.bosch-climate.us/files/201009031238250.GWH715ES_English_12.2008.pdf

I cannot find a service manual, or service bulletins:
http://www.bosch-climate.us/support-center/downloads/bosch-manuals/earlier-models.html

http://www.digelair.net/pdfs/TECHLIT/BOSCH/MANUALS/Bosch-ProTankless_AM.pdf
http://www.bosch-climate.us/files/201009031238250.GWH715ES_English_12.2008.pdf

Above are the manuals required to diagnose and service your error code.

EA: No flame ionization detected with water flow.
Verify that all manual gas shut off valves are open. Check gas type. 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. Check three wire connections to ignition group on the lower front of the heat exchanger are secure. Check gas pressure. Check venting specifications are met. Improper venting may cause premature failure of the flame sensor rod. Check that the minimum power fan speed has been adjusted to the proper value. 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.

http://www.bosch-climate.us/files/201008311810050.G3-11_A3-E3_Error_Code_Troubleshooting.pdf
Check out Link for help.
I have same problem.

either you main controller is bad, or the thermo couple is faulty


Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/sean_54c3a3dc48a7773c

The vent pipe you use is the correct size for the heater.Longer runs require bigger pipe.I also would check to see if the water is getting to hot.

Look at the manual to see what code E4 is