Tip & How-To about Heating & Cooling

Tankless Hot Water Heaters When is The Time and the Place to Use Them

In the past few years the tankless hot water heater has become much more popular. Should this type of water heater be used all the time for every job or is there some places that they just are not the right tool for the job?

Your water heater is something that you depend on everyday to give you a constant supply of hot water for the many things that you do. If you are building a new home or are just looking to replace an existing hot water tank then you need to look at all the possibilities to make a good decision about what your nest appliance should be.

Tankless or instant water heaters are a great way to make hot water. They will provide you with a constant somewhat limited supply of hot water. This means that the flow of the water is limited. Because of the way they heat the water instantly the volume of water running through the heater has to be controlled to get the temperature rise that you desire. The tankless water heater does not store any hot water. When it detects a flow of water in the water pipe the heater turns on and then it shut off when the flow stops. This feature will save energy if you only use water intermittently.

The downside of this type of water heater is seen if you need large flows of water at one time. The amount of fire that is needed to heat large volumes of water quickly is very high and it kills the efficiency that you expect from the unit. Also if you are continually using water then the instant water heater is not the way to go. Because the heater makes hot water so fast a high BTU flame is needed and the instant efficiency is not very good. The savings of this type of heater comes from it not storing water and keeping it hot from long periods of time till it is needed.

So if you are just using hot water a couple of times a day and most of the time the heater is just sitting there waiting for you the instant water heater may save you money. If you are using water a lot of the time or are using large volumes of water quickly then it probably will not be the appliance that you want. Also remember to check on the pricing of these tankless hot water heaters. They are very expensive to buy and install, often costing twice what a normal tank type heater would cost. Check to see if your pay back will be enough to cover the difference in the cost. In many situations the savings will be enough to justify the extra cost. And many times the savings will not be there. You need to research your options and make an informed decision.

Tankless hot water heaters are not well suited for every situation, but in many cases they are a very good money saving option.

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Have been running extremely hard water thru our Noritz NR98-DVC for a couple of years. Unit is not functioning properly. What, if any, damage could result from using this hard water? Could there be


Replace single-handled faucet cartridge, and see if hot flows to that faucet again.
http://waterheatertimer.org/Crossover.html

Exposing tankless to hard water causes reduced efficiency within a few months, and can cause Total failure of parts within two years.
Do not expose tankless to more than 11 grains hard water.
Here is research pdf conducted by water softener industry comparing tankless andf tank-type:
http://waterheatertimer.org/pdf/Battelle_Final_Report.pdf

To possibly solve problem temporarily, install softening system, delime tankless unit using white vinegar. Delime yearly. It is fun for whole family. And who doesn't like a project schedule.
http://waterheatertimer.org/pdf/Rheem-De-lime-tankless.pdf

To solve problem long-long term, install tank-type gas water heater from local box store for $350.

Oct 12, 2012 | Noritz NR98-DVC-NG Natural Gas Indoor...

1 Answer

Noritz NR98-DVC tankless water heater won't give hot water thru a single valve fixture. Gives us all the hot water we want on a double handled fixture. Any suggestions on what to do?


Replace single-handled faucet cartridge, and see if hot flows to that faucet again.
http://waterheatertimer.org/Crossover.html

Exposing tankless to hard water causes reduced efficiency within a few months, and can cause Total failure of parts within two years.
Do not expose tankless to more than 11 grains hard water.
Here is research pdf conducted by water softener industry comparing tankless andf tank-type:
http://waterheatertimer.org/pdf/Battelle_Final_Report.pdf

To solve problem long-long term, install tank-type gas water heater from local box store for $350.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Oct 12, 2012 | Noritz NR98-DVC-NG 100W Freeze Tankless...

1 Answer

bOUGHT THE UNIT IN JULY 2009 WORKED FINE UP UNTIL THREE DAYS AGO WHEN I RUN THE HOT WATER IT RUNS FOR A FEW MINUTES THEN SHUTS OFF.


1) Rheem offers on-line chat, which you rarely see for typical tank-type water heater
http://www.rheem.com/products/tankless_water_heaters/customer_support/
http://www.rheem.com/hrc.aspx

2) Call local service technician, and put that person in your rolodex-wallet for future help.
Ask technician for tips and tricks for keeping unit working and needed maintenance.
They will gladly offer a yearly service.

3) Read manual several times to get accustom to yearly maintenance required for tankless water heaters. Tankless water heaters are maintenance heavy. All costs are energy.

4) Read manual several times and notice word troubleshoot appears many times.
Since tankless are complicated machines, many internal and external factors can affect operation, especially as unit ages.

5) Look at label on unit to identify exact product number. Identify same/similar product at Rheem, and become familiar with Rheem website
http://www.rheem.com/products/tankless_water_heaters/

6) Read other question/answers at fixya about Rheem tankless to become familiar with the tankless era
http://www.fixya.com/tags/rtg_74pvn

7) Install DIY tank-type gas water heater and avoid the whole headache
http://waterheatertimer.org/How-to-install-gas-water-heater.html

8) Add a comment for more free help.
Also take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

Mar 14, 2011 | Rheem EcoSense by 4.2 GPM Tankless Water...

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