I have a Paloma Hot water system with code C7 12 flashing there is a drop in the water pressure and not hot water is coming through the pipes.

Here is what should be going on.
There is a length of pipe between the hot water that is in your tank and the nozzle you are expecting to get it out of.
It is really possible the are nearly 3 gallons of water in those pipes, especially if the water heater is many feet from the faucet.
Now about the drop in water pressure.
Try the cold water.
Does it do the same as the hot? Does the pressure drop after 2 - 5 minutes?
If so, suspect your pipes are clogged with sediment. How old are the pipes and the house/apartment?
Does the water contain minerals that clog pipes?
If the cold water is good, and the hot not, I should suspect there is blockage in the hot water pipes, especially going in to or coming out of the water heater., or perhaps the faucet is clogged with rust or deposits.
God bless your efforts.

http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html


gene

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

bleed the system,sounds like an airlock issue

In several cases i have had to change the pcb board.... code 76 is no communication between remote thermostat and pcb..... this is a problem the first generation rheems seem to be having.... contact rheem if under warranty you will need to get pcb and program chip sent to you. Really need a experienced tech to install board and program it for you...... hope this helps...

Before calling service technician, open following links for error codes, Rheem/Paloma chat and tech support, and possible manual:
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
http://www.fixya.com/support/t3444443-paloma_tank_less_water_heater_flashes

Error codes are considered start-point for troubleshooting.
Tankless manuals recommend yearly service including burner cleaning, gas pressure and plumbing check, de-liming etc to prevent problems and so technician is familiar with that specific unit.

You have a clog in the hot water line.
If problem is at one faucet, then remove aerator and clean, then disassemble lines underneath sink.

If problem is at every faucet, then that moves search close to water heater.
Look at hot water line that exits water heater and trace that line to first Tee.
Look at cold water line that enters water heater and trace that line to Tee.
Clog is located between those 2 Tees.

Buy pressure tester that connects to hose thread.

Connect pressure gauge to hot water heater drain valve.
Then conduct same test you did at faucet.
See if pressure drops at tank.

If pressure drops, then clog is on cold side of tank, and probably hot side too.
If pressure does not drop, then clog is on hot side of tank.

Suspect 1 is any place two different metals join. For example galvanized pipe and copper.
Suspect 2 is supply pipes that exit top of tank. Take apart and look inside pipes for corrosion and sediment lining pipe walls.
Suspect 3 is elbow. Disassemble pipes and look for sediment and flakes of rust.
Suspect 4 is all suspects above, each having sediment and corrosion.

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

You have clog in the water line.
Since all hot water pipes are involved, clog is probably near water heater.

Buy pressure gauge at hardware store that threads onto hose connection.
Brady BTG 100 at Amazon
Picture of gauge

Check outdoor pressure for baseline pressure in your home.
Turn off electricity to hot water heater for an hour or two so there is not scalding water.
Open drain valve on water heater to see if water heater is clogged with sediment.
http://waterheatertimer.org/Water-heater-will-not-drain.html

Put pressure gauge on drain valve and compare with outside pressure.
Open hot water spigot on bathtub and see if tank pressure drops ... if tank pressure drops significantly with bathtub spigot on, then clog is on incoming cold water before tank, and could be on outgoing hot water pipes too.
If tank pressure stays about the same, then clog is on outgoing hot water pipes.

Clog can be sediment caught in cold water shut off valve located above tank. Open and close valve and test pressure again. Take apart incoming cold water pipes above tank and check for sediment. Replace valve. Look at condition of cold water nipple on top of tank.

Sediment caught at hot water elbow near tank.
Sediment can fill up old pipes. Take apart hot water pipes above water heater and see condition.
Look at condition of hot water nipple on top of tank.
You may have to take apart pipes up to first or second elbow.

Pipes can decay at joint where copper pipe connects to galvanized pipe. Check for copper to galvanized connections on cold or hot pipes and replace section of galvanized pipe. Copper pipe will probably be good, the galvanized pipe will deteriorate. Replace copper-to-galvanized joint with 3/4" non-conducting union from hardware store

I had the same problem with my Paloma a year and a half after installation...contacted Rheem 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.

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.

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