Series 200 Ultra Low-NOx Non-Condensing Indoor Tankless Water Heater (8 GPM, NG/LP)

I purchased the model 310U to replace a 23 year-old Takagi TK-2 that finally failed. Some careful measuring told me that I could install the new heater in approximately the same location as the old one without making any changes to the existing flue piping, and this turned out to be true. Gas and water piping required rework since all the connections are on the bottom of the 310U as opposed to the left side on the TK-2. I strongly recommend buying a new isolation/service valve set for the installation. My local M*n**ds had the Watts LFTWH series valve set in stock. SupplyHouse carries the A.O. Smith version, but it would ship separately from the heater and take an extra couple of days to arrive, so I opted to buy it locally. It really does simply the installation, and makes draining or flushing the heater so much easier... plus the pressure relief valve is included, so that's one less item to shop for. It feels a little strange to me to have an appliance like a water heater with a cord-and-plug rather than being electrically hard-wired, but this eliminates the need for an electrical disconnect at the water heater, so I just replaced my disconnect with a duplex receptacle. The 310U worked perfectly from the first powerup. The control panel is excellent and easy to navigate. Otherwise, it works very similarly to the TK-2 it replaced. The 310U does seem to deliver warm water slightly more quickly than the TK-2, but it might just be my imagination. The startup sounds are more noticeable with the 310U, but not what I would call loud. While running, it's nearly silent. SupplyHouse.com was amazingly fast processing my order and getting the heater shipped (free). The new heater was delivered in 2 days. The whole ordering process was extremely easy and efficient. They also offered this heater at the lowest price I saw anywhere. There was no need to shop around -- SupplyHouse.com was a no-brainer, and they have definitely earned my business in the future.

I replaced a tank water heater about a year ago, which until it was ready to fail after over 20 years, never had a single problem. The Takagi unit immediately had issues which resulted in no hot water, which in Vermont or anywhere can be a real problem. The first issue was a frequently clogged cold water filter, which on this unit is about the diameter of a dime and 3/8" long. My water is not particularly dirty, comes 460' up from granite then through a sand filter. For comparison, the commercial filters that Supply House sells and which I installed after multiple clogs are more than 20X the surface area of the worthless one on the unit. The next issue was with moisture in the combustion chamber. Most of these units are installed in a HVAC controlled room and will not have this issue, but mine is in a laundry room with no air conditioning. If your cold water pipes get sweaty, so does the combustion chamber, which will interfere with ignition. The only remedy I had was to wait for lower humidity days so it could dry out. The most recent snafu was failure of the igniter assembly, which I replaced and is now working. The problems I've had with this unit I would not have had with a tank water heater. When I eventually replace this unit, which may be sooner than later, I'm going back to a tank system. At least with that you have a small reservoir of hot water if something goes wrong. The only reason I'm giving this a 3-star instead of a 2-star is that their technical service is exceptionally good. 24/7 connection to technicians who are experienced troubleshooters who don't put you on hold. Unusual to find that level of support these days.