Power star 46-551701 blinking light - Bosch PowerStar AE115 Tankless Water Heater...

If its 1 blink every 3 seconds its normal operation.
Otherwise, this is the meaning of the various blinks:

No blinks = no poilet light (not enough power (in millivolts) to keep it lit.
2 flashes = insufficient voltage (in millivolts) to gas valve.
4 flashes = high water temperature (over heat sensor activated.
5 flashes = water temperature sensor failure.
7 flashes = gas control valve / thermostat failure.
8 flashes = Only occurs if the gas control valve or Temperature knob has been turned off And the thermocouple continued to produce electric power.
9 flashes = Combustion chamber temperature sensor open or shorted.
10 flashes = LDO occurrence was detected in the combustion chamber (contaminants).

look at breakers, there is two sets one in unit and one in breaker box. check presure to unit need 95 pis to set relay for heat, some have adjustment for this

Following link has power vent troubleshoot resources, with error codes and manuals:
http://waterheatertimer.org/power-vent-water-heater-troubleshoot.html

Rheem/ Richmond series products do not have service manuals posted online

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

http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent

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

62-24084-02 LED CODES
POWER LED - GREEN
ON - Normal
OFF - No power to board
OK LED - GREEN
One Blink - One hour retry delay
Two Blinks - Pressure switch failure (remains open)
Three Blinks - Limit switch fault
Four Blinks - Pressure switch failure (remains closed)
Five Blinks - Twinning fault
FLAME LED - YELLOW
ON - Good flame
Rapid Blink - Flame present with gas valve de-energizing
Slow Blink - Marginal flame

Question posted under Reliance gas water heater.
Add comment for different brand.
Age of heater is unknown.
Status light indicates one of the Honeywell electronic gas control valve.
Status light not blinking indicates that water heater gas control not receiving electrical power for power vent models.
Or thermocouple is bad on non-power vent models
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent

Depending on model, and age, the thermocouple can be tested and replaced. Or entire burner assembly is replaced.
http://waterheatertimer.org/How-to-replace-thermocouple.html

If the gas control valve has gone bad because of power surge or other anomaly, then the power-vent type gas control is removed from tank and replaced, while the non-power-vent model is module and can be snapped off front of unit.

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

Bosch will give free tech support to figure out your problem. 800-798-8161. Check your paperwork if it is still in warranty they will send free replacement parts. If out of warranty go to www.houseneeds.com for replacement parts. Check the "Flow switch" a long two tubes with two little micro switches and a little round hat or sombrerro that MOVES when the H20 is turned on. IF YOU HAVE ONE OF THESE, it should turn on one or two micro switches. If you have this part it should be described in your "Owners manual". If you no longer have the owners manual you can get one free at www.bosch.com It will give you trouble shooting guide and or you can call them even out of warranty then purchase replacement parts.

F76 is a communication error between two quick connected heaters. To clear the code, disconnect power from both heaters, wait 20 seconds, then reconnect power.

It seams alot of people have this same problem All must get ahold of manufacturer and report this it must be there pump's thank you for useing fixya