Tankless Water Heater Problems - Part 2 (Specifics) 

Thank you for making these very informative videos. I bought a new house with two separate hot water systems with two Rinnai heaters. I was getting a 'failure to light' code on one of them, had only hot water in one shower and only cold water in another but all the sinks worked fine. It took a while to figure it out and my local certified Rinnai repair guy though I needed to replace the burner because only the left half was lighting. He didn't know it was a two stage burner and with more demand the right side would actually light. After reading the Rinnai manual I tightened all the electrical connections and sure enough the igniter ground was corroded so that fixed the Rinnai code but it didn't help the showers. It turned out that both shower pressure balancing valves were stuck--one in the cold position and one in the hot position. After three months of "what the heck?" I have everything working. I do have a loud whistle coming from the vent pipe of one of the Rinnai's and just putting my hand near the vent the whistling stops so I'm guessing I need to clean out the vent. The end of the vent has a screen cover and there's nothing around it to block it and the inside of the pipe does not look restricted but I'm definitely going to attempt to clean it. Thanks again for the videos.

Thanks so much for your comments, I was trying to decide whether or not to remodel apartment units with tankless water heaters in order to save space. I think your comments really put a realist view on my decision making. thanks anna in oklahoma

I just wanted to say THANK YOU for posting this video. My Rinnai Tankless was installed about a year ago and started having problems staying hot about a week ago (no error codes). I descaled it / cleaned the filter and it didn't fix the problem. Guess what??? The problem ended up being our outdoor shop faucet that my wife had left on (hot and cold) and connected to a hose nozzle. This was causing a "cross connection" that you described. Turned them off and FIXED! Thanks again!

Hi Scott. Following up on this. The issue was the thermostatic mixing valve was broken. The plumber replaced and everything has worked great since. Thanks!

Hey, Scott. Thank you for your excellent videos on tankless water heaters. I am greatful that there are people like you, who explain to other ignorant people out there that these products have so many advantages and benefits over the old-fashioned obese pots of constantly boiling water. My Rhinnai gas heater looks just exactly like yours. It was installed in 2008 by a specially trained tankless installer. He told me he actually had to take a special class to become certified. I am very happy with my Rhinnai water heater, but I have one concern. The exhaust pipe is installed horizontally with a slight slope TOWARDS the heater instead of away from the heater. That may cause problem in future with the condensate backing up into the heater. Moving the heater up by few inches is not an option because that would mean cutting all the pipes that run to it, including the gas pipe (which is pain in the butt). I could probably drill a new hole in the concrete foundation wall and re-position exhaust pipe few inches down to create that slight slope away from the heater (94 degree bend), but the patch in the wall would look ugly, especially on the outside. I saw a video on "Ask This Old House" channel where they attached a clear vinyl drainage pipe on top of the heater, but they didn't show how to do it or what kind of adapter/coupling to use. I am not sure how that method works. Is that an effective way to get rid of the condensate? What are my options? What would you suggest me to do? Thank you, Eugene

Thanks so much Scott, very helpful videos! I have a Rinnai tankless propane model R75LS at a remote cabin in NY state, and earlier this winter, I drained it and the well-pump in the wrong order…so, when I came back a week later, I thawed out the basement for a few hours, and then the heater started raining and flooding the basement. Apparently a little water was trapped and froze; my fault. I shut everything off and could see that a pressure/safety gasket at the bottom left, inside, had come undone, possibly to protect the unit, and I don't know how to most easily set it back. Thats where the water was leaking all out. It seems like it would be easy - could I do it myself without paying a lot of money for a service person to come in from an hour away? Thanks for your attention.

Had a code 11 with a beeping on a 5 yo RL75i. Flushed the unit for an hour and cleaned the filter. Flushing and cleaning annually since 2 years old when we first got the code 11. This time 6 months in and got the code 11 again with no hot water. Turned off and on and now working fine. Thank you for your videos. Very helpful.

very good vid, a lot of info. thanks...

Thanks for the low down on tankless water heaters.

Good review of potential problems with tank-less water heaters. The only thing I disagree with (as a former Navy Nuke Machinist Mate in #1 RX and ER, and BSME) is always using a 'certified' technician. When it comes to electrical installations, I will always get a licensed electrician, because electrical stuff is 'lights and mirrors' stuff to me. Water heaters, heat exchangers, air compressors, water supply piping, etc., I don't trust anyone else doing that kind of stuff. Case in point. My wife wanted to install solar panels to augment our house and farm usage. Electrical. Looked up the solar system installers approved by the State. Got a Master Electrician listed as approved for solar installations in Southwestern Ohio. Started out with just 24 panels using Enphase microinverters. That's a system that uses the Duke transmission lines as its 'battery' when the panels are making more electricity than we use daily. This idiot knew electrical stuff, for sure, but when it came to common sense 'mechanical' stuff, he was a TOTAL imbecile, yet approved as a certified installer of solar systems. After he was done installing and the system was up and running, I finally got up on the roof (I hate heights) to inspect his workmanship. Not only were the solar panels butted up end to end with no gap for expansion, he used an electric drill to install the stainless steel bolt and nuts that held everything in place. I found that out when we tried to loosen the bolts to create a gap between the panels. Plus found that he actually mounted some of the panels like 'diving boards' completely wrong according to the installation paperwork that was taped to the back of each panel. You don't put stainless steel threads together FAST. In nuclear piping systems 304 stainless valve caps had ACME threads on the cap and valve bodies. If you did not Neolube (graphite alcohol mixture) the threads first before engaging them, and turning the cap on slowly to keep from galling the threads together (like welding them), you would not be able to get them apart easily, if at all. We had to grind at least three dozen fasteners to get them off of the solar mounting hardware. I ended up having the idiot remove all the panels, and when he got done I told him "bye, bye," and reinstalled all of the panels and wiring all over again from start, the RIGHT way! As Clint Eastwood said in one of his movies, "A man has to know his limits." I've seen too many idiots with all kinds of certificates, even Master Criminal Investigators, who have all the credentials but don't know $#!+ when it comes to doing the job correctly. Plan it out. Make drawings. Watch RU-vid videos. Note where you will need some help. Then get the job done!

I actually am new HVAC tech and I found this video to be very helpful. So thank you.

Hi Scott, Thank you for the video! It was very informative and I just got a house and this help me understand a bit more on the temperature setting. I am an electric engineer and always in search of optimizing my home. My question. Every time the electric tankless water heater turns on I get a dip in the electric Voltage. Have you address this issue in the past? How have you solve it? I was thinking about installing a Capacitor to handle the kicks but have not done all the research yet.

extremely good explanation very good

I have Rinnai R85 model, recently it began displaying LC - limescale code... I wanted to do basic Flush with vinegar, but couldn't because the Flush Valves we jammed stuck. I plumber ( also certified to work on Rinnai Tankless ) came changed out the entire Valve Kit... He also said once I did the Vinegar Flush & clean the filter, the code should stop appearing.. Well after flushing the valves with Vinegar, the Code is still flashing and also my water pressure throughout the house has decreased significantly. Why is the error LC code still flashing ? (even after a flush and I could clearly see the the difference in the vinegar.) Will be calling the plumber back today?

Thanks again, so many more of our questions answered!

Thanks for your info. One last question on which Rinnai tankless would you suggest ? Our house has 2 full baths there is only 2 of us & we never take showers at the same time. We have never ran a dishwasher or a washer during bath time either, Talked to 3 installers which pushed for more costly high btu units with no good reason behind it. Just stated the bigger unit won't run out of hot water.

thank you, thank you, thank you. By simply lowering the temp on the unit we now have hot water . I was having to run the water and then cycle the hot water valve at the unit (Rinnai) before the fan would start or the burner would lite. now all seems fine....

you saved me cleaned the filter and its working great and they wanted 600.thank you keep it up! your info is priceless

Hi Scott, I have watch videos 1-3 and I must say you do an excellent job on them. I have a question regarding my Rinnai R75LS. I just moved into my new home 2 weeks ago. The home is heated by the hot water heater as well through a radiant heating system hooked to the Rinnai. The issue that I am having is that the water does not stay hot. I have it set at 130* and whenever we turn on a faucet or shower to hot, it gives us either luke warm water or hot water for about a minute and then goes back to luke warm. I have tried lowering the temperature setting to 120* thinking it may be a mixing issue, but that does not solve the problem. The Rinnai revs up when you turn on the hot water, but then revs down after about 45 seconds or so even if the hot water is left running. What do you think might cause this issue/do you have any suggestions for a do it yourself fix? Thank you in advance!

Great video, I live in Brazil and we use tankless systems here. I have installed US faucets and now I get no hot water, beacause of the flow rate restricters in the outlets of the faucets drop the water pressure outgoing so that the water heater cuts off . But, if I remove the restricters I get hot water, how can or can a tankless water heater flow adjustment be done to where it comes on with lower water pressure out of the faucet.

Very good and informative.

Thank you for the education. I have a AO smith (510c), it's my understanding that's it also Takagi. It's was installed by the builder 3 years ago, works ok, until lately, it's been getting stuck on standby mode (orange light). I cycled thru the output temperature setting, and turn on the hot water in order to get the burners running again (green and orange light [in use indicator] will come on). What can be done to get this thing back to its proper running mode? The tank is flushed regularly, filter cleaned and a scale inhibitor is installed at the cold water in let.

Scott, I appreciate your videos on the tankless water heaters. we had a Rinnai installed in our home about 10 years ago by a licensed plumber that was referred by a local company that sells these. The unit has run well and I flush it typically every two years. I've started having an issue with it and thought I would share it with you. After using the unit, it should go into cool down mode for a minute or so afterwards to purge. what i'm seeing is that even though the hot water has been turned off the unit continues to run and water is coming from the overflow pipe. I turn the unit off and allow it to cool and reset it. At times it starts, runs, and stops as designed. Other times it doesn't. I contacted Rinnai and they said they've never heard of this problem and don't know what to tell me. I asked for a licensed Rinnai service tech in the Cincinnati, Ohio area and they told me there isn't one. With that being said I think perhaps there's a issue with the control board or sensor of some sort but thought you might have advice on it. thanks again, Bob Chance

Looking into a tankless system for my house, thanks for the info, real "meat and potatoes" tips and directions.

Thank you! After hours of troubleshooting we found that the plumber that demoed the basement bathroom just hooked the vanity hot and cold together instead of terminating them individually. The hot water flows again!

Question. Would it be practical to install an electic instant water heater after a standered tank water heater. And use the tank as a pre heater on the lowest setting. I have a well with cold water and only space for a 40 gallon water heater and live in Oregon. Any thoughts?

@ Scott Gregg, got a question, I am in a apt complex with a tankless water heater, lots of people have problems with hot cold, & hot again then cold and hot water again, is it possible for the tank to be the issue, or is it more likely to be a valve in wall situation, that would be the idea for the,issue? I don't think it is cold sandwiches because it will happen 5-15 minutes into a shower, any idea?

A year ago in Cambridge MA our 2 yr old Rinnai R75 shut off. Our licensed plumber/installer found significant water inside. Snow had covered the vent. We had to buy a new unit. Three days ago it beeped and shut off again. We are in Florida. Again our plumber/Rinnai installer found a little water and moisture inside the unit which is 11 months old. No snow this winter. What has caused this? Thanks for your answer. Anne Watt

I have a Noritz EZTR40 and was getting error 121. After quick call to Noritz had it up and running in 10 minutes! The rep told it was really error 12 where it would ignite and then shut off. He walked me thru cleaning the flame rod and ignition plug with a DOLLAR BILL, could of used a Scott pad but did not have dry and clean one. Don't hesitate to call Noritz great customer service.

thanx for the information

My Rheem on demand lp is 7yrs old,Love it ,sometimes when I shut off the hot water faucet the heater has a faint beep that won't shut off unless I hit the power button on thermostat, then turn thermostat back on and beep stops ,but have plenty of hot water ?

Thanx Scott... I will try that...our Rinnai model is the R53 and was installed in 2007.. Our shower heads are the 'navy type" heads that do have a water saving/ flow restriction functionality built into the head...can I increase the flow rate at the tank heater to help with this problem? Other option would be to remove the current Navy shower heads and use non flow restrictive heads...Any thoughts??? Steve

Scott, I have a consistent E012 error on a Navien natural gas heater. It runs maybe a few hours and then gives me the error. Seems only to occur when providing heat to baseboards, but not when just providing hot water (or maybe it occurs with both but the hot water is intermittent, so I haven't seen that). I measured the gas pressure and it seems high. Is a high pressure able to cause that the same as a low pressure?

Hey Mr. Gregg. I have a Rheem Tankless unit and it makes a loud bang during start up. It's like the gas builds up and it ignites too hard. Any ideas? I've had it for a couple of years. It's always done that since installed. It's so violent the front cover flexes with it fires.

Excellent videos, very helpful to understand some key issues and how very technical problems can be. Our Rinnai is 10 years old, and has run completely without problems for all this time until now. Started making lots of rumbling sounds and also we noticed a very small bit of leaking. No error codes. Service technician checked everything out, did find a dead roach inside blower and cleaned that well, but it still makes rumbling on high fire. Other than that was operating perfectly when tech left, but now will start up occasionally but not most of the time, and is leaking a good bit more and cannot be condensation because the unit won't run. Any thoughts as to what this might be?

Thanks!! Good info.

I have an older Bosch Aquastar 125B. Water temps are really low at some outlets and others such as a shower you have to turn on an adjacent sink to get enough hot water to shower. I another bath I can turn on the shower and sink simultaneously and both deliver less than warm water. Then when you shut the sink off the shower gets to a good warm shower temp for about a minute then back to that not quite warm enough temp. Unless I play w/the sinks and showers, turning them on and off to get heat from them the water never gets hot enough to even wash dishes except at the utility room sink, but even that isn't terribly hot. The unit was descaled w/vinegar for about 10 hours in late 2015 and is currently set to max temp as well. I've watched 2 of your videos and now on to the third! I need some help here!

Scott, I've had my Rinnai tankless hotwater heater for at least 10 years. After some initial installation problems, it's run like a top ever since. That is until this morning. The water is not reaching the temperature to which the thermostat is set. Basically, the water is lukewarm. The hotwater heater continues to display the temperature to which it is set and does not display any error codes. What should I do? THanks.

We had a thunder lighting storm go through Atlanta last night. Now the fuses are blown and I replaced them twice today and every time I turn the power on the fuses blow still. I think lightning shorted the board. So frustrating. Now we have no hot water and I can’t afford to replace the unit.

Thanks for the tips. I have a faucet in the master bath that will literately takes minutes for the hot water to begin. I have heard maybe it's because it is further away, but it is on the other side of the wall where the the outdoor Rheem tankless water heater. The garden tub, which is located beside this faucet, does not take as long. It is set on 120. We thought we would turn it up to 130. When needing warm or hot water, we don't even turn on the cold water. In other words I don't think it even reaches 120 , if it did we would need to turn on the cold to mix in the hot. It sounds like you do not recommend this, what is your suggestion?

My unit froze and split last winter, cold air came in through the exhaust. I live off grid so, only have electricity part time. Would that be the reason that it froze and split? Do these units need power 24/7?

Great video! You mentioned if the temp is too high (above 120) and you're mixing more cold water it could cause the heater to shut off. Why would it shut off? Reaching a temp limit or the flow is slow and doesn't see a demand? Thank you for your help.

hi scott, I have a Jacuzzi tamkles, its giving an error 14, I tried de-scaling with vimigar and after an hour the vinegar is still clean! could this be a flow sensor problem, re routing the vinegar out instead of pushing it through the heater exchange? please help!

Mine also has no control pad. I hear you showing error codes on the key pad and I don't have that.

Hi Scott great video it was helpful, I couldn't find part 1 though

I would like to ask I have a problem that nobody seems to be able to fix. What I have the hot tap open and it isn't that hot but I just want it slightly cooler I open the cold tap just a little bit and slowely but it would cool down for a few seconds then hot water qill run out of the cool tap. We even got someone out to try and fix it but they don't know either . Any idea how to fix this problem

Hi scott, I have navien 240 boiler. The problem I am having is that when I turn on the hot water faucet, initially it gives me hot water. But (within 30 second) slowly the water temperature goes down and (after a few minutes) i get no hot water. The boiler was installed 2 years ago and this problem started two days ago. any suggestions? Thanks

Why would I blow the 3 A fuses inside the unit? I installed new fuses and they blew again. Rheem is sending new control panel but worried about reoccurrence of problem.

I have a 20 year old tankless Rheem water heater rmtg-74pvn2. I was doing a bathroom renovation/remodel converting to a shower with diverter valves. The next day my wife said we didn’t have hot water. I was getting no codes on the thermostat. The unit was going on but not going up in heat… by now you guessed it and in minute 13 of your 17 minute video you talked about a cross connection. I was pressure testing the line before we close the walls up and both the hot and cold shut off valves for the shower were open and of course without valves in the mixing and diverter valves we had a giant cross connect. As soon as you started describing it I paused the video and went down stairs closed the hot water valve and had instant hot water. I’ve been researching for 2 or 3 hrs and trying to figure what changed that would make the unit stop working. As a note, I live in Wisconsin, very hard water so I have a very good water softener and get over 5 gpm through the heater today after about 20 years. The units is in my dusty but basically temperature controlled basement because it’s part of the house . Also I run my water heater at 110 F to keep the flow up. Older units like mine need more flow than the current ones.

mine just started shutting off randomly it works when I go just off the hot water valve next to the heater and open it again you can hear the machine start up again but thats just a temp fix till my landlord gets this thing repaired. its seems like it only works when its built up pressure

Scott, Good overall background info....I have a Rinnai Tankless heater that will sometimes fluctuate between hot and cold (especially in a shower) Unit was professionally installed and is descaled/ cleaned annually....I am not seeing any error codes on my heater...Any thoughts or ideas?? Thanx, Steve

Scott I have a Jacuzzi Tankless Hot water heater, I get an error code 10 every once in a while, but the vent is clear and connected well to the unit. If I power off and on it clears the error. The error normally occurs after the unit is providing hot water for a few minutes. Any suggestions?

I have a Navien. So with no LC error code, you pretty much just need to ballpark it when you need to perform a periodic flush? My unit is giving me no error codes but the water is not going above 77 degrees anymore. Air filter is clean though.

i get hot water everywhere in the house. The master bath has two sinks, bath tub and shower. All have hot water very quickly but the shower takes for ever to heat up and when it does it is intermittent at best, either hot or cold. The gas is on, vinegar flush for 90 minutes, no mineral scale anywhere and no error codes. Help

I have a code 25 on mine. How do I clean a condensation trap?

I have been having the sandwich issue and I have a npe-240a-ng that just got installed July 2021 and the last three weeks it's been horrible and this issue was not there up until three weeks ago what should I do

I have a unique question. My Rinnai tankless was professionally installed with high output gas meter outside in 2008. It was very quiet when new. One flush was done in 2012. But now whenever it runs it makes a lot of noise. Why?? Up until today I watched your video,my set temp. was at 130. Now I have lowered it to 120.

Scott, Very informative. Quick question. I have a new construction project and my plumber recommends Navien. You mention not caring for those. Any particular reason? Obviously you're a big Rinnai fan but what are the critical differences between Rinnai, Noritz, and Navien? FYI, house will be in Southeastern US and indoor install. Thanks.

Hi we have a Rinnai tankless water heater and my entire family will be away for a couple of months, so we were thinking of shutting down the unit. Now there is a panel that has an OFF button on it, and btw it is not leaky, so I was wondering if it’d be okay to just shut if off by pressing the button. I did some research online and all of the forums and answers were about a leaky water heater, and most of them involve draining the water inside which I don’t think is necessary for a perfectly-working unit that just needs to be turned off for a couple of months. But I still want to be sure about it.

Hey Scott, absolutely love this video. You're very clear and easy to understand. I have an issue that wasn't addressed though, that I was hoping you'd be able to assist with. I have a 2016 A.O Smith unit that just started giving me issues. The unit with go into "in use" mode when I activate a hot water source, however it turns back into "stand by" after about 15 seconds of hot water. I have cleaned the filter and flushed the system and the units control board is not indicating an error code, just a static green light. I was thinking it could be the flosensor, but wouldn't that trigger a code? Any help you can suggest would be greatly appreciated. Thanks my man.

Good video. My Bosch tankless is fluctuating wildly at the heater and running into overheat error codes. I have descaled it a few times (after 10 years of not servicing) and replaced the ignition & ionization unit, but still fluctuating. Any suggestions?

Great video and maybe you can help. I just had a rinnai RUC98i installed in North Carolina, I have it set to 125 degrees. The problem I have is if my daughter is taking a shower (2.5GPM) and my wife goes and starts a bath (6 GPM) ( I measured the flow in each) the pressure in the shower drops and the shower is now cold and stays cold. So you have get out of the shower or turn up the hot water than it is too hot, then you have to adjust it to get it back to usable. My plumber says everything is working right and maybe it is the piping in the house. The tub is much closer to the tankless than the shower. Any suggestions would be appreciated

Hello can you tell me what's causing my code 13 on my Rheem tankless water heater

Hey Siri I have a Renée R90 4LSIN. Gave me a code 1015 is great making a lot of noise when the blower Motor is running. Pretty sure the bearing is failing need a linkto see how hard it is to change out. Thank you much sir

Scott, we have a Noritz tankless water heater and our problem doesn't seem to be covered in your video. Our problem started last winter, we live in Florida and noticed on very cold mornings(cold in Fl terms) 30-45 degrees we have no hot water, nada,none from the hot water tap. Have had system descaled professionally, the problem still continues. Our error code is 16. System works fine during summer, but this morning with temps in 30's no hot water. We have someone coming next week from the gas company to check the gas fittings. Turning the system off and back on does fix the problem temporarily but not ideal to run outside when it's really cold. Any ideas?

Thank you for posting the three videos. Just recently, our heater started shutting off after about 5-8 minutes into showering. It gets really cold for about 3 minutes and then the warm water will return. Do you know why it would be doing this?We bumped the temp down from 120 to 110. If we cut on hot water on at another faucet ,while someone is still in the shower, the red "in use" light will come back on. We have a Rannai heater, and use gas.

I maybe putting you on a spot with this question . What would be a approx. a fair price on a small tank less unit the water & gas hookup it all right where unit would go on wall. The venting would go up thru attic on a one story house trying to get some idea on cost.

Hi Scott, thanks for your video. my tankless hot water tank has no code also no hot water. only4 year old machine. when I turned the hot water on, in use light is on, less noise than before, I had cleaned the filter still not working, do you know how to fix that issue? thanks again.

Just found your channel. Great info! I have a Richmond ng tankless. It's only 3 months old. Every now and then, while in use, it emits a fairly loud hum or vibration noise. My installer came and checked the psi for the water and NG. Said everything seems ok. I still have that 'hum' or whatever at times. Is that noise normal? I'm thinking it could possibly be something as simple as where it's connected to the existing plumbing of the house? PVC to Pex. Thanks.

I have a navien and it is leaking and has an error code E002. What should I do? It's turned off

Scott, I have a Rinnai. We get loud hammering when the dishwasher or washing machine run. I've installed hammer arresters on both. No luck. Not a problem with any other use of water in or outside the house. The loud hammering sounds like it comes from around the water heater, which I clean out once a year or so. Ever hear of this problem?

My R53 has been working great 8 years. This AM, no electric. Gas good. Flow and filter good. Power supply good. No power to key pad so no error code. Fuse? PC?

Scott....my Rheem tankless water heater keeps throwing a 13 error code. We turn it off to reset, and turn it back on and it will sometimes be fine and other times keep throwing the code. It was installed before we bought the house 3 1/2 years ago. I know the previous homeowners had it installed as part of the buy sell agreement. Any suggestions?

We have a Rinnai tankless heater installed about 8 years by the builder in central Maryland. For the past year or so we have only intermittent hot water. There's no error code, and we've had three different technicians (two different companies, plumber and HVAC) come out to look at it, say it's supposedly fixed, and hundreds of dollars later it still isn't. Could be something not the how water heater, like the cross connection thing, and do you have any suggestions about what that could be and who to call to fix it? TIA

Scott I should have told you it's an electric unit and yes of course I checked the breakers and they appear to be fine. I even turned the thermostat down the other way just to be sure . It's in the correct position. Thanks

I've got a Bosch 125x that strikes off batteries. It was going through batteries and we finally found out it was trying to start (striking but not lighting) without water running. I turned it off to stop that but turned it back on and now it does nothing. I figure it's the control box. We got two of these fifteen years ago, and they still run great.

Hey, Scott. I have an issue with an electric hot water heater that was recently installed. It is an Ecosmart ECO-11. Everything appears to work perfectly until the hot water is shut off, then even though the unit appears to shut off and it sounds like it shuts off the water in and around the unit continues to eat up to the point that I can't touch the outlet connection. Is this an electrical issue or plumbing. This is a mystery and I can't seem to find an answer anywhere. Before this unit I had a Heatworks Model 1 and the presure built up so much that it blew the sharkbite connector off the unit. For now I have been turning the breaker on and off to take a shower so that I do not destroy this one as well. In the beginning I thought it may be the unit, but now I think it may be the house or the install. We followed the instructions well and used the 6 awg wire with a 60A breaker. Any input would be appreciated. Thanks

I have issues with my unit in the fall and spring where it gives a code 11 and no hot water. After a couple of tries it eventually works. Once winter or summer hit it's fine. Any suggestions

I have a Bradford White unit and it looks almost identical to your Rinnai, only it has a temp controller in the front of the unit... It too has the "LC" error code... Great piece of equipment, no problems so far and its been installed 4 years... Parents older Bosch unit ( 14 years in service) has been not bad, BUT had to replace the exchanger coil once already and it is not compatible with their Bosch dishwasher... go figure.

Nice vids! I was hoping to learn why my unit vibrates tremendously making a loud sound when I first turn the shower on every morning?

"Code 25" - We were having trouble with the drain line to the outside freezing, causing blockage of the condensation line (no way to insulate the entire line because it is inside a brick wall) resulting in no hot water or lots of condesation tank draining and resetting. Our professional installer connected the condensation line to the wet vent pipe, with the required p-trap, to drain into the septic system so there would be no ice blockage potential. Unforturnately they don't work weekends and after he left on Friday the "Code 25" happened at least 5 times. It doesn't sound like there is any water in the condensation line(of course, we can't be sure), we are certain there is no ice in the line, and draining the condensation tank and resetting the unit allows the unit to run and heat water for a little while. Any ideas?

Hi Scott, the rental maintenance people installed a tankless water heater in our rental home a few weeks ago. It has never worked appropriately. The water from our taps is either scalding hot or freezing cold regardless of how you set the faucet knobs. The rental company has sent out 3 different people to look at the issue and all have said it's a "sandwich effect" but it sounds like the sandwich effect is a momentary issue, not an issue of water fluctuating between freezing and boiling the entire time you're in the shower (15-20 minutes). Its like the two temperatures never mix. Any ideas how we can fix this?

I am a homeowner DIY'er. I replaced a 40 gallon gas fired tank type heater in 1985 with a Thermar 100,000 BTU tankless heater doing it all myself. It was very straightforward and it's been running fine for all these 31 years. The only maintenance issues I've had is I've been getting 12-14 years from the rubber diaphragm that senses water pressure drop when hot is demanded. That operates the mechanical gas valve. The unit has no other moving parts, needs no electric, and has a standing pilot. It's about an hour job to remove and replace the diaphragm. Twice in 31 years ain't bad. I measured gas consumption before and after installing. Gas use is down by 50%. The heater has paid for itself time and again. Wonderful to occasionally take a sinfully long hot shower with no fear of running out. Mine is old enough that the capacity is low enough you can only use hot water at one location at a time, not a big deal in a small family. After about 15 years use, I removed the heat exchanger and soaked it in dilute 10% hydrochloric acid (concentrated Muriatic acid is about 37% so dilute it about 1 + 3 with water) to remove hard water deposits. It was a total waste of time. There were almost no solids left behind when I evaporated the flush water in a Pyrex baking dish. That means there were next to no minerals deposited inside the heat exchanger. Our water is fairly soft, but not completely so. After putting it all back together, the performance was identical in terms of time to get water at X temperature rise. So. I would take exception to your firm advice that people only have tankless heaters installed by a professional. If you read the manual and are a competent DIY'er, you should have no problems. I agree with you that sizing of the gas supply is important. You just need to understand how to size the pipe properly according to the tables the manufacturer provides as far as how many 45 and 90º elbows you have and the length of straight runs. You don't want your heater to be gas-starved. Maybe what we could agree on is that just like there are well trained competent professionals and there are some hacks out there, there are competent DIY'ers and hacks as well.

Our electric EcoSmart 27, installed by a certified electrician, has worked great for 2 yrs (I'm in TX.) A few mornings ago, following a storm, we woke to no hot water. The temperature light still comes on. We soaked the heating elements in vinegar per the EcoSmart techs instructions. (2 of the 3 elements were blackened, scorched looking - ? Is that normal? There was no other buildup.) We changed out the 3 Amp fuse - even tho it looked fine - still no hot water. I'll call the tech back on Monday, but in the meantime, just wondering if you have another suggestion ... I've enjoyed your videos.

I know this is an older video, but I have a question for ya. A friend's Rinnai only works in the evening. She say's there's no code and that she can run it for 20 min in the morning and still no hot water. A plumber came out and said they cleaned the unit, but I'm not sure what they actually did. Any clue why it would work in the evening but not in the morning?

what is wrong of my tankless shower heater if i click to ON its automaticaly heat abnormaly even in not HEATING POINT ARROW pls help me and thank you

Wheres the link to the first video? Thanks so much for all this information.

I have a Rinnai CP 71201 without a display so I don't know the error code and we are not getting hot water. The first thing I did check was to make sure I paid the gas bill. LOL then I came to RU-vid to find help. When I look thru the glass I can see a blue flame light up for a second at the most then it shuts down. I've checked the vent outside and there is nothing blocking it. I'm guessing descaling it would not be the problem. That would be for blockage right? I pulled the two rods out and the one on the right had a little buildup on it and I removed it. Any ideas? Oh and I pulled the filter and checked that too.

My Rinnai RU98 just stopped giving hot water. I see no code. You never told us how to see the code? Is there any key presses I need to do to see the error code ? Anyway I unplugged it from AC power waited 10 seconds and plugged it back in it gave hot water for about 10 secs and then the water went cold.

Can you please link part 1 in your description? I cannot find it in your video list.

good video. thanks👍👍

Our builder had a tankless water heater put in three years ago when we built our home. We opened our utility room and saw a puddle under our heater. We discovered the unit was dripping from a corner. Any ideas? Do you service heaters in Manassas, Va?

I've got one for you! My tankless water heater wasn't igniting during the Winter I had to keep resetting turning on and off and finally when the weather turned warmer started heating up meaning the weather and now works without a problem!! Any ideas what's the problem by the way by the way it is leaking water. Didn't work in winter and now in summer it works great

Scott maybe you can help me. my tankless unit is a Power STAR . I just checked the temperature of the water and it's 88 degrees . sometimes it feels warmer but it is never hot. I have the thermostat turned all the way up. the unit is only used 4 months a year. it's a winter condo in Florida. it does not have any codes on it and I know you said it doesn't matter but its three years old which in fact makes it a year old of use. Any feedback would be appreciated. thank you

I am unable to locate your video part 1, my tankless water heater stopped making hot water when I turn on the water heater it shows 120 F on the monitor, but no hot water at all, I listen to the water heater small device attached to the wall I hear click sound from inside when the faucet is opened. but after a while the number 120 change to 11, my model is ( N-0751M ), any help or advice would be appreciated.

We have the rinnai on our second home. It worked fine up until recently. Now we have code 32 showing and no hot water. Van you tell me what this means? What is the fix for it? Thanks.

Hi scott. Big fan of your videos, really need your advice. Our tankless rennai started leaking and we are looking to replace. Pls advice which rennai model to go ahead with for a 3 bath home. I shortlisted RU199iN but want your word on it. Also, have options for getting a rental tankless which seems cheaper than owning one, but looking to get your word here. Thank you so much!!

Hi Scott, thank you for this video. I have a story and a question for you. Perhaps you can answer it. A couple of months ago, our heat sensor pipe in our tankless system failed, leaving us with no hot water and heat. We got that part replaced by our HVAC company. Roughly a month later, we had an error code that said there wasn’t enough water going into the unit, so it couldn’t produce hot water. We had to use a fill tap on the unit to put water back in and raise the pressure (the pressure gauge needle would also drop into the lower end of the green zone). I called my technician back and he found a small leak around a 3 way diverter valve. He replaced the value and it was fine for a couple of weeks until it started really leaking. He got some special screws from the manufacturer (called flowmax) and that stopped the leak and the pressure. However, at the same time I saw the this most recent leak, I noticed that the water level in one of our toilets was lower than normal. It fills to the normal level when you flush then slowly lowers until it’s lower than normal. I don’t know if this is related or some coincidence. Now that the tankless system is fixed, I’ve noticed that the hot water pressure and cold water pressure in the main bathroom is weaker than before, even though the pressure gauge is in the middle of the green zone. If I have the hot water tap on, it starts out strong and hot, but then gets cooler and weaker after a couple of minutes. And then oscillates between hot and cold. But still weak pressure. Same with the shower. I had it set to 60 Celsius, but I changed it to 49 C after your recommendation, but nothing changed so I set it back to 60 C. We are not the original owners of this unit, as we moved in about a year ago and the unit is about 5-6 years old. I don’t think it’s ever been serviced. Thoughts?

that was very informative. am looking into going thankless, as we can have 10 people in the house on the weekends and we all like our showers, which means we have to space them out in the morning. during the week, we have 4 people who like to shower. not too bad, if me and my older nephew hit the shower first. as we're quick and don't like popping outta the shower, looking like lobsters stepping into a sauna (like my sister and neice like to do). If they all DO happen to beat me to the shower because I overslept. like last weekend, I ended up waking up rather quickly! It can take that old electric water heater quite some time to "recover". We live out in the country and don't have natural gas. and we find that in our area, propane can be quite expensive. there's only so much room in that "closet" and I think that tankless would be the way to go. There are other times when nobody will be in the house for an extended period of time. like 3-7 days, and it doesnt make sense to keep a hot water tank hot for all that time. I was looking into your brand, as I heard it advertised a few years back and believe it to be the superior brand. but I guess I have to do more research. either way, I found this video very informative. we don't have a lot of issues with out current water heater as far as maintenance issues. it's just the lack of volume and recovery time that's the most pressing issue. I see there's more maintenance involved with going tankless, but nothing that can't be overcome. if it keeps the water hot, and can save me money in the long run, it seems to be worth the extra attention that my current water heater doesn't need.

Hi Scott, thanks for the video. Do you know why my instant hot water system keeps shutting off? I cleaned it and everything works fine. It just turns off by itself on one of the odd nights and then I have to have someone go and turn it on after the tenants in basement complain.