Rinnai R94LSi Natural Gas Indoor Tankless Water Heater, 9.4 GPM

I installed this over a 3-day weekend to replace a 40 gallon tank heater. I kept the install straightforward without additional reciculating systems or buffer tanks as I like to keep it simple. Prior to purchasing the 94LSi, I read a lot of reviews and was a bit worried about the "cold water sandwich" effect. After a month we only rarely experience this when I bump up the temp to 140F. When I leave the temp at 120F we never experience the sandwich effect.The wait time for hot water is about the same as we used to wait for water from the tank style heater; maybe add a couple seconds but it's not a notieceable difference in wait time. The biggest comfort change I noticed is that the temperature is consistent while taking a shower. With the tank style heater I'd have to adjust the hot and cold a few times during the shower, but with the Rinnai 94LSi once I turn the shower handles they stay that way the whole time and the water feels the perfect temp the entire duration.If I go into the water heater room while the unit kicks on, it sounds like a cross between a cat purring and a airline revving up its engine quietly in the distance. The main reason I upgraded to a tankless is for the space savings, but now I'm starting to like the endless consistent water temp as well. I was originally skeptical of tankless units and avoided them until I ran out of space, now I'm so glad I went tankless!Max temp: Although this model is advertised as going up to 120F, it will do up to 140F with a DIP switch setting underneath the cover. The max is limited to 120F without this switch setting for safety reasons. It will go even higher with a commercial temp controller option. I found that when the power goes out, it remembers my temp setting when power comes back on.Gas line: I did almost everything myself, and the only part I hired a plumber was to run a second 1" gas line from the meter. This thing needs a good gas flow so if your gas line main branch is not large enough, it's important to branch a new T all the way from the meter. Half the plumbers told me my existing gas line was fine and the other half said I must run a new line. None of them bothered to do any calculations, but when I researched the gas line sizing tables on the web, I confirmed that my existing gas line would not handle the demand. So double check on those contractors to see if they're doing proper analysis.Service valves: If you're good with soldering copper, then installation is simple. There is nothing complicated about installation other than basic plumbing and mounting. Be sure to install a service valve kit such as the Rinnai (Webstone) WRIK-C. If you use this Webstone valve don't forget to remove the rubber gaskets prior to soldering, and put plenty of teflon/dope on the gas relief valve and turn it real tight because these Webstone valves are notorious for leaking at the gas relief valve if the thread is not turned super tight.Venting: The other main parts to finish the project are the vents. These work with the Ubbink vents which serve both the combustion air intake and exhaust in one double layer pipe. There is an Ubbink install guide PDF on the web that gives a pretty good idea of the parts to order based on where it's exiting the house. Installing the vent was simpler than I expected - just push the pieces together and it forms a tight seal. When cutting the vents to size, cut the metal inner pipe about 3/4 inch longer than the plastic outer sleeve for proper mating.There is an actual-size paper template that comes in the box to assist with mounting on the wall. I broke open the wall and put some 4x4s between the studs for extra support, then used 8 stainless steel bolts to mount the unit to the 4x4s.The manual says that the indicator will show a message if there is scale build up. So it even senses when it is overdue for maintenance. If you get frequent brief power outages, you can plug this into one of those computer equipment UPS battery backup devices to keep the hot water going since this uses electricity for ignition.I posted some pictures in the product images above to show what the internals look like with the cover open.

Okay I did my homework, I looked at all makes, read reviews and after seeing that Bosch have terrible follow up on there products and rheem have trouble with there electronics I went for this the Rinnai. Now work out how many things you could have going at one time, say showers, dishwasher, washer, etc and then go a little higher on what you would need output wise. i did this a went for the R94LSi, great unit and made in Japan. Be prepared you will need at least two people to move this baby and especially when you go top mount it on the wall its heavy. Fit the lower bracket on to the wall first then put it up and fix it then the top bracket which is still attached to the unit, best way I found. Ran all the pipework ourselves and got the BrassCraft TK30RB21-24 Tankless Gas Connector IPS Valve Kit with 3/4-Inch ID by 24-Inch Gas Connector and PR Valve for it, in fact that was the only parts that were a pain and actually leaked so be prepared to have to re-attach them several times. That kit is very expensive ($125) but it does have the right valves and a pressure relief valve that you have to fit in case of a blockage or if the unit just keeps going for some reason. Read many problems over gas supply as most pipes are 1/2 inch and you need 3/4. Well we used our friendly ace who had elbows that stepped up from 1/2 to 3/4 then ran the pipework to where we were fitting the new unit. Runs fine no trouble, the amount of pipe used helps the gas flow run enough so no gaps in it. Clever thing with rinnai is 1) they give you a template to fit the unit, great but in the end you have to hold the thing up to fit it anyway (with the help of a friend or more due to its weight) 2) it has dip switches inside and if you read the instructions, most models only go up to 120 degrees but we felt it wasn't quite hot enough so if you flip a dip switch on it allows the temperature to be raised to 140 degrees, we found 125 was perfect.The worst part was fitting the vent pipe, its a damn hard and I make no excuses here and expensive. Got it online at a company in NY as it was cheaper to ship it from there all the way across the country than to get it here, it doesn't allow for much adjustment either so we went along the thought, get the heater, then fit it up, then make the pipes up and then figure out how much vent pipe you need. The 45 degree elbows have to be bought in pairs even if you want just one, do not ask me why but thats the way they sell. We ran it through the wall but check how far from a doorway it has to be, the info on the web is a pain to find but there instructions states 12 inches in most states. We used the expanding foam the fill in the hole round the pipe to seal it up. We also bought the condensation trap and fitted it, takes about five minutes to put in but it supplies everything with it except the pipe that runs from the bottom...duh! The vent pipe must run downhill slightly towards the unit and the condensation trap is fitted to collect any moisture that builds up as the vent pipe is two pipes, one inside the other, hot air goes out through the middle one and cold air in through the outer pipe. And be sure to strap the pipe so it doesn't move.We connected the rinnai up but left our old heater in place just in case of problems so we could reconnect if necessary. All worked perfectly and that old thing is gone.One point to make, it does make a little bit of noise like a small jet engine starting and rumbling a teensy bit so make sure its not fitted to a wall perhaps the other side of your bed headboard, or right under your bed, if you have teenagers who take late showers or you put your washer on late and go to bed you will hear it but its not the worst noise.All in all a good unit, been in and working for two weeks now and no setbacks.