Why am I getting no hot water from tankless water heater

SOURCE: Tankless Water Heater - Frozen???

I had them same problem with my AquaStar 125 back in 2005......it hasn't been that could around here since then until last night and it froze up again. The problem is the negative draft. This can be solved with the Power Vent Module and the AQ1 flapper....at least with the 125. It prevents the back drafts.

SOURCE: No hot water

The code # 11 is a code that warns of "no ignition" and the causes of this error code are too many to list. I would suggest that a qualified tech. perform a diagnostic test and repair.

This is not a task for the "do it yourselfer"

SOURCE: Noritz tankless water heater not producing hot water

I called Noritz error code 16 is a overheat problem. Noritz say's to flush your coil with vinegar or CLR.
Use a small pump to recirculate the CLR or vinegar through the system for 45 minutes and flush with fresh water. This worked for me.

SOURCE: Paloma PTG 74PVN Tankless Water Heater

did you check the filters on the the water valves, i am not exactly sure about your codes that are shoeing but if you could read it and post them, i know on some of the units 76 means there is low water pressure and the filters are behind 2 caps one on each side above the shut off valve take off the caps and remove the screens, clean them and replace them ,, make sure you turn off the water on both side first or you will get wet

SOURCE: richman gas lp tankless hot water heater. used for

I had the same problem with my Paloma a year and a half after installation...contacted Rheem\Paloma\Richman customer service (800-432-8373) and they recommened a local installer in my area. The technican diagnosed the problem as the "flow control valve"; he managed to get Rheem/Paloma to cover the part under warranty...I only had to shell out the money for the install.