Hi there. This is probably not your usual Rinnai code 12 post.... I have a Rinnai V75IP propane tankless hot water heater that I bought new 3 1/2 months ago, in June. I hired a plumber/electrician to install it, but he was not a certified Rinnai technician. Ever since it was installed, I have encountered the dreaded Code 12 problem, where it periodically cuts out and stops producing hot water, beeps, and flashes a Code 12. It does not reset itself--I have to turn the hot water completely off, wait a moment, and then turn it on very slowly, to just a trickle to make it work again. At that point, I can very slowly open up the faucet and usually get it to keep producing hot water, but if I open up the faucet too much too fast, it will kick off and flash Code 12 again. I rarely get the Code 12 problem at my kitchen sink, which has a lower flow rate, but my bathtub, shower, and utility sink faucets have higher flow rates, and this inevitably happens at some point whenever I use those. Cold showers are the worst.
Now, I am reasonably sure, after reading threads here and talking with some plumbers and pretty much everyone in town, that the problem is that my (former) plumber installed this with a 1/2" propane line instead of 3/4", over about a 20' run. I may also have an insufficient regulator. I don't think there is actually anything wrong with the heater itself, only the installation. I understand that I need to have this propane line, and possibly regulator, replaced. Unfortunately, I was laid off from work, and I'm afraid it will be several months at best before I can afford to have this line replaced. To complicate matters, I live in rural Alaska, and can't hire a Rinnai technician. In fact, we have a serious shortage of plumbers in this little town, so my options are very limited, and despite the popularity of this very model of Rinnai in our town, our resident plumbers seem to know very little about them, and don't care to learn. My original plumber messed up every aspect of my system so badly that I'm not willing to let him work on my house anymore, even to fix his mistakes. The next plumber I hired has advised me on what to do, but he backed out after realizing what a mess my first plumber made, and he doesn't want to deal with it. Tried hiring a third plumber, but he's booked up for the next two months. And, the fourth plumber in town is a drug addict. At this stage, I have to try to make this work as best I can until I can secure a plumber, and the means to pay him.
So, I'm looking for stop-gap measures I can take to make this Rinnai sort of work until I can get the line replaced. One plumber suggested that I partially close the ball valve on the water line going into the Rinnai, to restrict the flow so it has less water to heat at one time. I did that, and I think it's sort of helping, so that it cuts out less frequently. But is operating my water heater like this bad for the heater? Is it putting undue strain on the unit? He also had me replace my regulator. I calculated my maximum propane use (between the water heater and my propane range) and consulted the propane shop on which regulator to use, but this plumber was surprised when he saw what they gave me--so I'm still not entirely confident that I have the right regulator. It's better than what I originally had, but still not cutting it.
Would it help matters if I put flow restrictors on my shower and faucets?
Is this problem going to get worse as winter sets in and my incoming water is much colder, so I have a much bigger temperature rise? I am on a rain catchment system, so my water can be quite cold in the winter. I thought I was buying a more powerful water heater than I really needed, just to ensure hot water in the winter, but it doesn't seem to be the case.
Is there anything else I can do?
Thanks in advance for the help!