Flushing a Tankless Water Heater

[Steve Peterson]

If my tankless did all that, I'd hate it too. The Rheem heats water at a pretty low flow. I shave with a low flow of hot water and I'm the only user on the system and I get constant hot water. I have a low flow shower head (I guess everyone in CA has those) and have no problems with constant temperature water.

Tankless is an old technology - you'd think all the manufacturers would have worked out the bugs by now.

Regarding two showers and a dishwasher running at the same time and the tankless not being able to keep up - tankless heaters are made with different maximum flow rates. If you draw more gallons per minute (GPM) than the tankless is rated for, you will not get constant hot water. You have to size the tankless to the expected maximum flow.

I agree that the cost to switch is high - I had to reroute plumbing and add an electrical circuit. But I wanted to recover the space used by my tank style hot water heater. I may, or may not, ever recover that up front cost, but I'm glad I made the switch. My tankless works well and I like never running out of hot water.

Mike

Ours is a 143K BTU unit, supposedly good for 6.35 gpm. It may be slightly less since it is at 5000' elevation. It is good to know that there are other brands out there that work like they are supposed to.

Steve

[Jim Becker]

I had a Bosch Aquastar 250 in our addition, but replaced it last fall with the same Paloma (Wai Wela) I installed in the older part of our home after a hurricane flooded out our basement a couple years ago. There is no comparison...the Paloma performs in a stellar way. The Bosch didn't last and support was terrible. My only (minor) complaint is that the newer one is noisier than the older one and that's noticeable since it's in living space. (2nd floor laundry room) The "endless" hot water is enjoyable and we're only burning natural gas to heat water while we are actually using hot water. Does it cost less in the end? It depends. Because we had to have a special "shortie" tank type water heater due to head room, it's replacement cost was only a hundred dollars less than the tankless unit that replaced it. So for us, we are saving money.

Oh, the other thing I like about the Paloma I have is that it vents with PVC. That was a requirement to even put one in the older portion of our home. The Bosch required very expensive stainless steel venting. Being able to use PVC brings the cost factor way down.

[Colin Giersberg]

We have a Rinnai and we love it. My wife always took long showers (still does) when we had a tank type water heater. After she would get through with her shower, I would wait 30 minutes or more for the water to heat back up. Once I would get in the shower, she would come in to the bathroom to brush her teeth. She always turns the faucet on full blast, and needless to say, my hot water did not last as long as my shower did. We finally decided to get a tankless unit. We have not had any issues with running out of hot water, although when the washer runs water again, the temperature does drop in the shower for about 5five seconds or so, but then it warms back up quickly. When the April 27, 2011 tornado hit near us, we lost power for a week. The tankless heater is nice when you have no household power. We ran a 5500 watt generator the entire time and just plugged the tankless unit into it. Still had all the hot water we wanted. I can't imagine ever going back to a tank type unit anymore.
If anyone is considering a tankless water heater, check with your city or county water utility. They may offer a tankless water heater for a substantial discount. We use Limestone County Water and Sewer and we bought the Rinnai whole house unit for $750. We did have to get our gas line replaced because it was too small for the gas log fireplace and the Rinnai to operate at the same time. After replacing the gas line, they sent out two employees to replace the gas meter since this was too small as well. After it was all said and done, we paid approximately $1450 for everything. I think it could have been done cheaper if we could have gotten the right plumber to begin with. The first plumber came out and hung the tankless unit, but he could not install the gas line (not licensed for that) and he would not install the vent pipe. That was $100. The next plumber (different company) removed the undersized gas line and installed the larger size. That was $600. There was no cost to replace the gas meter. The Rinnai cost $750. I learned a lesson there. The second plumber was able to do all the work, but we just didn't call him first.

[Bill Cunningham]

Our Rinnai has a digital display on the front, and When running the dishwasher, we set it for 140F. When in the shower, I set it for 104 or 106 (depending on my mood) Open the shower full hot, and step inside. The Rinnai monitors and controls the heat, and it never budges no matter what else is turned on.. Ours is 180kbtu input and draws 3 amps on a standard 3 prong plug so it can also be plugged into the generator on a power failure. They ain't cheap, (mine was 2k installed [after eco grants] but because I didn't have a outside facing wall to mount it on I needed a special through the roof vent that handles both intake and exhaust) but over oil I'm saving $550 a year based on oil prices in 2008, So the payback time was under 4 years. Well worth the investment..

[Colin Giersberg]

We have our Rinnai installed in the garage, with the vent making a 90 degree bend and exiting out of the wall. This did require extending the natural gas line. This is partly why we had to have our gas lines up-sized from the meter to the gas fireplace. After that, the pipe is back to the regular size supply line. Fortunately, we have a water line near the Rinnai, so we didn't have to have much plumbing done.