Tankless LP Water Heater

[Sigarms]

In the winter I bump them up to about 140 and in the summer I drop them to 120.

I just turned them up to show where they can be set

You seem to forget this conversation we a couple of years ago. Unless you put in new water heaters recently and bought the commercial controller to set the temperature setting higher than most residential applications, I'll assume you still have the same commercial water heaters that were installed more than a couple of years ago?

I should correct myself as well. It is not impossible to set higher water temperature settings on some residential water heaters, however, considering the fact that in less than 5 seconds you can get major burns that require hospitalization at 140 degree water temp, it does seem kind of dumb that you would do so. On the current Rinnai models, residential models can go no higher than 120 degrees with the MC-91 controller. At least that is the information they gave me last year when when I was at their US facility in Georgia.

Also feel that children can be taught to not take a 3 hr shower or waste hot water

And that is one reason why some people don't actually save money.

The advantage to a tankless system is that is heats water only when you need it. Four people taking a shower in the morning learn (or are told) to minimize the amount of time in hot water because you may run out of hot water. Take those same four people and instead of taking a 5 minute hot shower, make it a 15 minute shower, and multiply that by the days in the year, and you're gas usage may actually go up.

One of the most important factors in figuring the right size unit isn't the amount of people taking a shower (even at the same time), but the possible maximum flow rate at one time. Exceed the flow rate and add the temperature rise into account, and I know more than a couple of people who were not happy with a undersized tankless system. More than one occasion I had to measure the flow of a tub or shower with gallon buckets because a homeowner wasn't happy with their tankless heater.

That said, odds are, two or three people will be fine with a standard tankless model.

 

[Dargo]

You really don't have to teach teenagers not to turn the water on all hot and then stand under the flow for 5 seconds. With the ground water ambient temps in the winter, about 140 works just fine to keep an acceptable flow for 2 showers at the same time no problem. I have no babies in the house who will fill an entire bath tub with hot water and slip in for a soak. As I mentioned several times, I have commercial units in the home and a residential unit in the guest house. Generally, if just one person takes a shower, they simply plug in 102 degrees on the remote temp pad by the shower and you have the same temp water for as long as you want to shower. It kind of spoils you if you've ever done it.

I have found that I prefer my coffee maker to brew my coffee each morning at precisely 192 degrees. The same goes for hot chocolate. Any more feels too hot and any less just doesn't feel hot enough.

Still, after having tankless water heaters for years, I see why the rest of the world uses tankless water heaters rather than waste energy by constantly heating a large tank of water 24/7.

 

[Alan L.]

We have one large Rennai unit in our new house (well its 3.5 years old). Its OK, we MIGHT save a little, we use about $30 - $35 a month for propane just for hot water. I think electric would be a little more, but not enough to make a big difference.

We have a well and while the water if very soft, I have to remove a screen and clean it every few weeks, as the hot water flow gets pretty low if you don't. I set it on 120 and use it like a regular water heater, mixing hot and cold. So far thats all the maintenance I have done. I didn't know there was something you could take out and clean. Guess I need to check that out.

You can take a couple of showers at the same time, though you can tell the water is not quite as hot, but the heater will compensate by firing up hotter and then the water will get hotter again.

I have no problems with trickling hot water. Not sure why you would need to trickle hot water, but mine will. No hot and cold sandwiches noted - no difference from a tank heater. There might be a delay of just a second vs a tank heater, but not enough to notice. Our problem is we only put in one and it takes a long time to get hot water to the other end of the house.

My concern is that it will cost alot if I ever have to replace it - can't just go to Lowes and buy a cheap tank heater.

I guess overall I am pleased - I don't think a tank heater would work well filling up my wife's 80 gallon bathtub. And I can shower and still have hot water - thats the best thing.

 

[nickel plate]

When I tore out our four year old electric water heater ($$ it was burning out the element every year for the past two years $$) to make room for the new propane Rinnai, it seemed reasonable to drain the tank for ease of movement. I could only siphon about 2/3 of the liquid out and the water color was darkening at that. Once removed, I laid it on it's side on a set of concrete steps and what came out of it would make a maggot vomit.
Our 5 year old Rinnai Continuum has an MC-45-4US controller that can be set manually between 96 and 140 degrees but will default to I believe (it's been a while) 110 degrees in a power outage. That too is a slight problem as it requires a shot of electricity to fire up-thus no standby hot/warm water that the old soup can provided.
Our monthly electric bill dropped $45.00 and since there are just two of us, our on demand propane costs are minimal and just the relief of a grundge free system was enough to warrant the overall cost.

 

[valley]

I put one in about 3 years ago. We like it. We have natural gas here. We just bought another place where there is only propane and the water is hard.
We have been planning to put in a tankless there also, I never thought about the hardness of the water. Is there anyone out there that has a tankless and hard water?

We have one sink in the kitchen plumbed for gray water to the yard, we plan the same for all the sinks and tubs at the other place.

 

[JD 4520]

My experience with hard water and any water tank is not good. They are very tough on pipes and but especially on tanks where the water sits in the bottom. I don't know how it may be different on a tankless. If there is anyway to install even an inexpensive softener I would recommend it.

 

[OKnewguy]

We have a Bosch Aqua Star tankless. For the first 4 years at our house, we did not have softened water. The dishwasher element got to be about 3/4" thick. We put in a water softener about 5 or 6 years ago. I have the unit set to just soften the water enough to prevent build up. Anyway, during the first 4 years, we never had issues with our tankless. I will say that our tankless, is a low tech one and not sophisticated like some of the ones nowdays. I do know that Rinnai units will tell you when they need to be descaled and if they are installed properly, it is very easy. You need valves at the entry and exit, and then you use a solution and a recirculating pump to clean the units out. This maintains maximum efficiency , btw it sounds worse then it is.
Dave

 

[SpringHollow]

i bought a kit with my tankless unit that allows me to switch some valves and pump things like vinegar through it.

Service Valve Kits - WAMHomeCenter.com

I also added this which helps prevent buildup:
Aqua-Pure AP430SS - WAMHomeCenter.com

Ken

 

[zzvyb6]

Both Home Depot and Lowes here in Brighton don't recommend tankless if you have a well. Problem is variation in pressure and flow rate and its effect on the heating elements (eg Warranty).

I pay about $25 per month for 40 gal natural gas hot water (2 peeps and 4 clean dogs) and I like a HOT shower after my hockey games. I need HOT water after every contact with poison ivy, too. It seems to 'burn' out the oil and stops the itch.

 

[SpringHollow]

Sounds like you are talking electric? Large electric units are not usually recommended any where, well or city. A natural gas or propane on demand can produce very hot water for as long as you like where as a tank unit will cool down with major usage. Lots of people with wells here using on demand and i have not heard of any problems. The two negatives of tankless (at least mine) are that you have to have a flow of more than a trickle to turn it on and they cost more than a cheap tank heater.

Ken