Rinnai v53e Propane model. Unit shuts off 2mins into shower. Minimum flow related.

shawn4401

Hi, I have a Rinnai v53e that will shutoff mid shower (right after you shampoo lathered you hair and are blind) and give no error code. I have done extensive trial and error testing and have narrowed it to the minimum flow. I tried removing the restrictor disks on the shower head and the problem goes away. The problem seems to only occur in the warm months (guessing input water temp related, unit is in Florida where city water is really not that cold). Unit will operate fine as long as I run the shower head on full blast HOT water, so it feels like bathing infront of a pressure washer. The unit is hot water only for a single family house. Unit never shuts off from dishwasher or sink usage. Unit seems to operate fine if BOTH showers are running. I have had propane company test gas flow (inches?) and it is more than sufficient per then tech. My question is..can I adjust the temp of the unit to compensate for this and lower the minimum flow requirement so I dont have to have my skin blasted off by insane water pressure.

Thank you for any input.

Tom_133

Have you also tested your theory by running the sink faucet on hot while showering? If while running the sink and shower you have no issues you may have chased down your issue. You want to post a pic of your install.

shawn4401

It is at my vacation house, but i will try your idea out and snap a picture next time i am there. If it is infact the flow, would adjusting units temp up or down help low the chance of the unit shutting down in the summer months?

Jack

Your unit should have a touch pad that will allow you to access the flow rate within .1 gpm. As well, the touch pad can access the last ten faults. If the unit is faulting out and you shut off the water, the unit will reset. Your manual will tell you the sequence to get both items. You can also access the actual hot water outlet temp exiting the unit.
The minimum flow on that unit is .4gpm and min fire is 10 kbtu. What is your output temp set at? With a tank if you do not have enough hot water you go down and turn up the temp. With tankless, you turn the set temp DOWN. Florida with its very warm ground temps can pose problems. If you look at the GPM x Delta T x 500=btu you can push the numbers around when you get the info from your unit.
I will say that a clapped out shower valve cartridge is frequently the culprit in this situation. If you aren't seeing a history of faults on the unit, look to your shower valve. prior to spending any money on anything, spend the time with the touch pad with an understanding of what it is telling you.

Slimpickins

Actually the activation rate on this unit is .6 GPM and 15,000 BTU min.

Jack

Checked the specs, and you are correct. It was not until the 75 model that it went to .4 and 10k. My apologies and thank you!