# Rinnai tankless water heater



## RLKMarble (May 27, 2009)

So i have a homeowner who wants to upgrade to a tankless water heater. My plumber wants to use a rinnai which i have never heard of. Any thoughts or comments on tankless (durability etc) and/or the rinnai brand?


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## akerplmbr (Dec 22, 2009)

They are top of line,thats all i use,most with 20 year manufacturer warranty. Just be sure you know the size you will need for the size of home its going to be installed in,,,ex.# of baths,etc. i always recommend gas units.


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## HomeElements (Nov 9, 2009)

Not sure about that particular brand, I have a gas tankless water heater in my home and I can say I'll never have another traditional tank system again. Alot more economical and endless hot water. Do not have to worry about a tank bursting, saves room and as I understand some insurance carriers offer insentives for using the tankless system.


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## vinpadalino (Dec 17, 2009)

akerplmbr said:


> They are top of line,thats all i use,most with 20 year manufacturer warranty. Just be sure you know the size you will need for the size of home its going to be installed in,,,ex.# of baths,etc. i always recommend gas units.


I still haven't installed one yet. I'm worried about them braking down. I don't have any parts on my van or even know were to start on those guys. What usually goes wrong with them?


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## bconley (Mar 8, 2009)

Make sure your plumber is well versed in the installation, there is a lot to know for them to work properly in some applications.
Sometimes you will need multiple units and or recirc pumps and larger gas service for performance equivalent to a tank heater


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## tcleve4911 (Mar 26, 2006)

akerplmbr said:


> They are top of line,thats all i use,most with 20 year manufacturer warranty. Just be sure you know the size you will need for the size of home its going to be installed in,,,ex.# of baths,etc. i always recommend gas units.


Ditto on the Rinnai. Best you can buy. Follow the manufactures directions.:thumbsup:


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## MLondon4 (Apr 30, 2009)

*Rinnai works fine but you need to inform the client*

I installed Rinnai in my own home about 3 years ago. The largest btu they had for home use. Two-story house with 4 bathrooms plus kitchen.

Installation requires 3/4 inch cold water supply to unit, plus 1/2 inch hot water to each sink and tub plus 1/2 inch cold to each. No hot water needed to toilets or outside hose bibs. Installation requires 3/4 inch gas line to heater. (If you are installing electric heater, then no vent needed.)
Heater can be placed on outside of house with no vent required, but if gas unit is installed indoors, then you need a proper vent.

Homeowner expectations: Instant hot water, hot service will never turn cold.

Homeowner reality: If you do not install a constant circulation pump, then the system must purge all the cold water in the line before hot water can reach the tub or sink. The time required changes depending on distance from heater, and volume of cold water coming out of the subject faucet. 
Without a constant circulation pump, the gas savings are greatest, but the loss of cold water each time the hot line needs to be purged is a wasted resource.
OK, so what happens if you install a constant circulation pump? The heat in the lines is constantly being lost to the surrounding air, so the heater must come on to supply heat to keep the water in the lines hot whether the homeowner is using hot water or not. This use of gas goes on night and day. In my opinion ( I have not tested since I do not have the pump.) the pump ends up using some amount of gas sort of like the old water tank system needed to keep the water hot. The benefit is that there is no need to purge cold water out of the hot water lines. So there is a need to decide whether to pay for extra gas with no waiting time, or to pay for extra water and wait a minute or two for the hot to arrive.

All the following info assumes that there is not a circulating pump installed.
If the hot water at the sink or tub is turned on with a trickle or low flow, the heater will not come on. It will flow cold water until the demand is strong enough to cause the flow sensor in the heater to turn on the heat. The heater needs to sense a strong flow from the hot water faucet to turn itself on. So the homeowner needs to turn the hot on strong and then wait for hot water to arrive.

Taking a shower - this is the biggest cause of frustration. If the hot is too hot, the person is tempted to turn down the hot water demand. Bad idea, because the water heater senses the reduced demand and shuts off the heat. This allows cold water to flow thru the lines until the heat comes back on. So the bather is trying to adjust the water temp while in the shower, and suddenly a minute or so of cold water comes thru the hot water supply. The proper way to adjust for too hot water in the shower is to turn up the cold water, but not to turn down the hot water.
So long as there is constant demand for hot water, the heater will keep supplying hot water. Two or more showers at the same time is no problem for the capacity.

There is a remote water temperature control that allows the homeowner to set the maximum water temperature. I have set mine at 106 degrees. That is not hot enough to scald a person in the shower with only the hot turned on. However it is too hot for comfort, so a little cold is needed to reach a comfortable shower temp.

Maybe the circulation pump would solve the shower problem. Not certain, though.

In three years, I have had no problem with Rinnai and no need for maintenance. That is no guarantee that I will not find a buildup of minerals in the lines. But the function of the equipment has been just fine.


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## Winchester (Jun 29, 2008)

If possible, I think it's best to consider more than one smaller unit as close as possible to the services to reduce the "purge"


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## SC sawdaddy (Oct 15, 2008)

I've heard of a Rinnai although I don't know much about them. My first scheduled job next year is to have a Bosch tankless installed in a previous customers house. I have always thought a lot of Bosch tools but I didn't know they even made tankless water heaters.


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## Teetorbilt (Feb 12, 2004)

This is personal. Times are slow so I finally get to do some stuff around the house.

The gas co. recommended this brand. I don't have gas so I need a 250 tank in the ground. $3,500 for all. I'm really trying to work out the long term benefits and haven't had time to crunch the numbers.

I also saw someplace that there are problems in low-flow situations without a circulation pump. I know that my pipes aren't insulated. I deal more with getting rid of heat (A/C).

Most of the year there are just two old folks here. Where would my approximate break even year fall? My basic figures come out well after I'm dead. I'm 58.


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## 747 (Jan 21, 2005)

Tell them to save the receipt. They can definately get a tax credit on this year income tax. Also check locally there might be a rebate from utility company.


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## 747 (Jan 21, 2005)

Teetorbilt said:


> This is personal. Times are slow so I finally get to do some stuff around the house.
> 
> The gas co. recommended this brand. I don't have gas so I need a 250 tank in the ground. $3,500 for all. I'm really trying to work out the long term benefits and haven't had time to crunch the numbers.
> 
> ...


I feel bad for you that times are slow. I hope things get better in jensen beach isn't it?


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## bconley (Mar 8, 2009)

MLondon4 said:


> I installed Rinnai in my own home about 3 years ago. The largest btu they had for home use. Two-story house with 4 bathrooms plus kitchen.
> 
> Installation requires 3/4 inch cold water supply to unit, plus 1/2 inch hot water to each sink and tub plus 1/2 inch cold to each. No hot water needed to toilets or outside hose bibs. Installation requires 3/4 inch gas line to heater. (If you are installing electric heater, then no vent needed.)
> Heater can be placed on outside of house with no vent required, but if gas unit is installed indoors, then you need a proper vent.
> ...


I had one plumber in house I built about 5 yrs. ago install a system that used a small electric HWT with a recirc pump the idea was for the hot water in the tank absorb the purge while the tank-less unit replenished the small tank. 
The recirc pump would would pump hot water in a loop through the tank and to all the hot taps.
There was a check valve between the HWT on both sides as I remember.
Does this make sense to any of you plumbers?


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## JamesNLA (Jun 2, 2006)

You were doing so good until the halfway point. Come on, aren't there any other tile guys, drywallers / painters or foundation guys that know all about these things? Too bad this particular part of this forum is beyond help.....Good luck hackers :laughing:




MLondon4 said:


> I installed Rinnai in my own home about 3 years ago. The largest btu they had for home use. Two-story house with 4 bathrooms plus kitchen.
> 
> Installation requires 3/4 inch cold water supply to unit, plus 1/2 inch hot water to each sink and tub plus 1/2 inch cold to each. No hot water needed to toilets or outside hose bibs. Installation requires 3/4 inch gas line to heater. (If you are installing electric heater, then no vent needed.)
> Heater can be placed on outside of house with no vent required, but if gas unit is installed indoors, then you need a proper vent.
> ...


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## Tinstaafl (Jan 6, 2008)

JamesNLA said:


> Too bad this particular part of this forum is beyond help.....Good luck hackers :laughing:


So you're what, a plumber who's an expert at forum triage? :laughing:

No forum, or forum section, is ever beyond help. However, those who choose to wisecrack instead of helping can certainly make it appear that way.


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## JTW (Jan 22, 2009)

Bosch is actually a large manufacturer in this market. I have a friend that works for them. I was considering going tankless, the biggest issue she made me aware of is that in the Northern climates where the ground water is much colder these units do not perform as well as they do in moderate climates that have warmer ambient ground water temps. She told me that by far they have more warranty issues from northern climates, apparently the units are working much harder to warm the colder water.... Needless to say I have not bought one as a result. I will be waiting untill I upgrade the boiler and evaluate the available options at that point.


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## jeffreyplumber (Jan 11, 2010)

I like all the work installing these systems. Consumer reports claims an anual savings of about 70 bucks on energy (gas tank vs gas tankless) 5 or 6 bucks a month. I just love all these green people doing the right thing! Personaly I think its a total waste of money. I dont try to talk any body out of it. Its great ! I get to run a new gas line new vent through roof. I want to start a maintnance program of flushing out the Heat exchanger of scale build up, from hard water, About 60 to 75 bucks for a quick service call Keep em Coming!!


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## crcu (Jan 14, 2010)

Hello everyone
I am starting a small preservation business in md; and comments or concerns that might help


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## radimeto (Jan 14, 2010)

RLKMarble said:


> So i have a homeowner who wants to upgrade to a tankless water heater. My plumber wants to use a rinnai which i have never heard of. Any thoughts or comments on tankless (durability etc) and/or the rinnai brand?


Its good brand,but if the house have a recirculation line use NAVIEN
thay have 15 years warranty and thay have build flood sensor inside the unit


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