Rinnai® Tankless Water Heater — Frequently Asked Questions
1. What are the power supply requirements for the Rinnai tankless water heater?
Rinnai tankless water heaters require 120 volts AC, 60 Hz and less than 3 amps.
2. Can I install a Rinnai tankless water heater myself?
Improper installation of gas appliances, including, but not limited to Rinnai products, can be extremely hazardous to you, your family and your property. Accordingly, Rinnai recommends that all of our products be installed by a Rinnai trained and licensed contractor or approved and qualified plumber or contractor according to pertinent federal, state, and/or local regulations. Improper installation of your Rinnai product can affect the warranty provided by Rinnai.
3. How much does a Rinnai tankless water heater cost?
The suggested list price for our water heaters tends to range between $900 - $1,995 depending on the model. These prices do not include installation or venting. For a more accurate price, please contact a local Rinnai dealer.
4. Can the Rinnai tankless water heater be used on RVs and Houseboats?
Unfortunately, our units cannot be used in mobile homes, modular homes, houseboats, or RVs.
5. Can a Rinnai tankless water heater be used to heat a pool or spa?
Rinnai tankless water heaters cannot be used for heating pools or spas. The chemicals used would damage the unit.
6. What is the life expectancy of Rinnai tankless water heater?
The life expectancy of a Rinnai is up to 20 years. Actual performance life will vary depending on water quality, usage rates, environmental conditions, and required maintenance scheduling.
7. What is temperature rise?
The maximum flow rate that our tankless water heaters can produce depends on temperature rise. Temperature rise is the difference between the set temperature of the unit and the temperature of the incoming ground water. For instance, if you set the temperature of the unit to 120 degrees F and the incoming ground water temperature is 60 degrees F, this is a 60 degree temperature rise. The lower the set temperature, and the higher the incoming ground water temperature, the more hot water flow the unit can produce and vice versa. If sized correctly for your application, the unit(s) should not have a problem producing enough flow for your hot water needs.
8. Can a Rinnai external tankless water heater be used in cold climates?
Yes, the Rinnai unit provides freeze protection for the unit down to -30 degrees F, as long as you have both power and gas to the appliance. The pipes feeding the unit MUST be heat traced and insulated to provide freeze protection to them. Rinnai strongly recommends the installation of an optional drain down system on units installed outside in cold climates. This system, if installed, will allow all water inside the unit to drain out if there’s a power and/or gas outage or a component failure in the product. See the owner’s manual for optional drain down system piping.
9. What types of fuel do Rinnai tankless water heaters use?
Rinnai tankless water heaters operate using natural gas or propane gas and have an electronic ignition.
10. Do Rinnai tankless water heaters have a UL Rating?
Rinnai tankless water heaters are not UL certified, but are certified by CSA International to ANSI Z21.10.3 Standard Gas Water Heaters, Volume III, Storage Water Heaters with Input Ratings Above 75,000 Btu/h. However, the following internal electrical components are UL certified:
1. Transformer E (UL 1411)
2. Relay (UL 41515)
3. Wire & Conduit (UL 1430)
11. Does Rinnai manufacture an electric tankless water heater?
We do not make an electric model. This is for two reasons, first the power requirements of electric units large enough to provide hot water for a typical household are prohibitive. For example a unit that can provide 3 gallons per minute with an 80 degree Fahrenheit temperature rise would require about a 150 amp 230VAC circuit. This is about 8 times the power required for a 3 ton central air conditioning system.
Second, the relative operating cost of electric tankless is MUCH high than natural gas. Based on national averages electricity costs almost twice as much per BTU as natural gas. Even with propane gas, tankless is considerably less expensive to operate than electric.
12. Does Rinnai offer a battery backup system?
We do not offer a battery backup system (UPS - Uninterrupted Power Supply) for our products. Please check with your local retail store for a UPS that may be suitable for your needs.
13. Can a Rinnai tankless water heater be installed in a mobile home?
We have specific units available that are certified to be installed in Mobile and Modular Homes. These units are part of our “VB” series, and include certain qualifying V53e models, too.
14. What is a cold water sandwich effect?
The term “cold water sandwich effect” is a term that is used to describe the introduction of cold water into the hot water supply line during frequent on/off operation of an instantaneous water heater. The cold water sandwich effect, when present, appears as a momentary drop in hot water temperature as it is discharged from a hot water supply outlet (i.e. shower, tub, or faucet). This phenomenon is present in the operation of all instantaneous, tankless style, water heaters, but is minimized with the high tech design of Rinnai water heaters.
The technology built into the Rinnai water heaters is designed to minimize the cold water sandwich effect. Rinnai water heaters are microprocessor controlled and when water flow through them ceases, they remain in a “ready to fire state” for approximately 1 minute. If water flow through a Rinnai water heater begins within the first minute following water flow stoppage, the water heater will fire back up within 1 to 2 seconds. This minimizes the cold water sandwich effect that would otherwise be experienced with a low tech tankless water heater. It should be noted that the cold water sandwich effect cannot be removed completely from tankless style water heaters. The safety standards developed to insure the safe operation of water heaters require a delay in the ignition sequence of all gas water heaters.
While the cold water sandwich effect cannot be completely eliminated from standard plumbing systems, it can be eliminated from plumbing systems that have a supply and return hot water circulating system. Rinnai has developed 2 methods to eliminate the cold water sandwich effect in residential hot water circulating systems.
The first (and preferred) method to remove the cold water sandwich from circulating systems utilizes a small electric tank water heater (powered up) that is used with a dual purpose. The small water heater acts as a mixing tank to eliminate the cold water sandwich effect from the Rinnai water heater and it uses its electric heating element to offset the heat losses from the hot water circulating system.
The second method to remove the cold water sandwich from circulating systems utilizes a small 2 to 6 gallon storage tank installed on the hot water outlet of the Rinnai water heater. This tank acts as a mixing tank to blend the cold water sandwich with hot water and eliminating its effect at fixtures.
15. What size gas line does a Rinnai tankless water heater require?
The gas connection on the unit is 3/4 inch MNPT but that does not mean that is the size your gas line should be. The gas supply should be sized to handle the total load of all appliances at your location. The Rinnai tankless water heater will add up to 199,000 BTU’s per heater installed at the location. Gas line sizing should be performed by the professionals installing your appliances. There is no way Rinnai can size your gas supply lines without detailed drawings showing the meter, regulators, sizes of these fixtures, and length of pipe from the meter to each appliance, and the BTU value of each appliance. Rinnai recommends that you contact your gas provider for accurate sizing.
16. Can a Rinnai tankless water heater be converted to a different gas type?
Rinnai offers a limited Field Conversion Program. Conversion kits from Natural Gas to Propane or Propane to Natural Gas are available for most models. Please have your installer/service provider call 1-800-621-9419 to find out if your model qualifies and to obtain a detailed step by step conversion instruction kit. These kits are available directly from Rinnai, and will be shipped only after the installer/service provider has contacted Rinnai’s technical support services and spoken to one of our technical specialists to ensure the installer/service provider performing the conversion is qualified to do so. The Field Conversion Program is available for product which has been installed and where gas type availability has changed. It will not be approved for use in conversion of non-sold inventory or mobile homes.
Top 5 Reasons to go Tankless
Already Own a Tankless Water Heater?
The life expectancy of a Rinnai is up to 20 years.*
Rinnai recommends periodic maintenance to keep your water heater running smoothly. We recommend having your unit serviced every 18-24 months.
Tankless Concepts' trained technicians will: check gas pressures; inspect flue system and burner; clean fan motor and in-coming water filter; check condensation system; check flow rate and temperature; and check error codes.
*Actual performance life will vary depending on water quality, usage rates, environmental conditions, and required maintenance scheduling.
1. Why does the fan continue to run after I turn off the hot water tap?
The fan is designed to continue running for a short time after the flow of water stops. This is to ensure constant water temperatures during rapid starting and stopping, as well as exhausting any residual gas flue products from the unit.
2. Why is white smoke coming out of the exhaust?
During cold weather when the exhaust temperature is much hotter than the outside air, the exhaust fumes condense producing water vapor.
3. Why don’t I have any hot water when I open the tap?
Make sure there is gas, water and electricity to the Rinnai water heater (power turned on and the gas is turned on).
4. Does a Rinnai tankless water heater have a standing pilot?
No, it has a direct spark electronic ignition.
5. Why does it take so long to get hot water?
The wait time to get hot water is primarily a function of the distance between the water heater and the point of use. The Rinnai is producing hot water within a few seconds of first water flow from a cold start. However you must purge all the cold water out of the pipe between the Rinnai and your point of use. For example if your kitchen sink is 50 feet and the water flow rate is 1 gallon per minute than it will take 90 seconds for hot water to reach your sink.
Having to wait for hot water after you open the tap is a pain. It also wastes water and energy. There are several ways to lessen this problem. First you should consider the placement of your water heater. Because of their small size Rinnai units can be placed in locations that you could never place a tank. If you can place your Rinnai close to your primary points of use such as your kitchen or master bath you will have the best of all alternatives.
If this is not possible you have 3 choices to eliminate the wait time or waste of waiting for hot water:
1. You could use a re-circulating line that keeps hot water following through a loop in your water system and then through your Rinnai. This is a poor choice for two reasons. First it wastes a lot of energy (probably at least $100 / year). Second, it will shorten the life of your Rinnai and reduce your warranty.
2. You could add a small electric hot water tank (only a few gallons) to the hot water side of your Rinnai and run a re-circulating loop through it. The Rinnai will still heat all the water and you will not shorten the life of your Rinnai or impact its warranty but you will still waste energy. You could lessen the energy waste by running the pump on a timer.
3. You could add a cold water line re-circulating system to your common points of use. This is a system that will circulate water from your Rinnai to a point of use by utilizing your cold water line as a return. This does not shorten the wait period for hot water but it does eliminate water waste and will not increase your energy cost like standard re-circulating systems.
6. What is the minimum water flow required to operate a Rinnai tankless water heater?
Please keep in mind that the Rinnai tankless water heater needs to see over 0.6 gallons per minute of water flow through the hot side to ignite and to stay in operation. If the flow rate falls below this level, the unit will turn off because it senses that hot water is no longer needed. There are several possible solutions to minimum flow rate issues: lowering the temperature on the unit to a more comfortable temperature to avoid cutting in too much cold water, cleaning the inlet water filter on the cold water inlet of the unit (sediment build up in filter can decrease flow into the unit), cleaning or removing the aerators from showerheads or fixtures, or replacing low flow showerheads or fixtures.
If you believe that this is not the issue, I recommend that you contact your original installer or plumber to service the unit. Please make sure that once you have a service technician on site that they call into our Technical Support Line at 1-800-621-9419 ext. 4491 MON-FRI 8AM-8PM EST for troubleshooting assistance and to prevent repeat service visits.
7. What type of periodic maintenance does Rinnai tankless water heater require?
Here are two pieces of periodic maintenance that you or your service technician can perform to keep your Rinnai tankless water heater running smoothly:
In-line screen filter should be checked periodically for debris: (Period between filter checks will be dependent on water quality). Ensure incoming water is turned off. The filter is located on inlet fixture below cabinet. Unscrew plug to remove. Expect some water drain off. Filter is a cylindrical screen.
Also, flush the unit periodically (Period between flushes will be dependent on water quality). This process will keep the unit free of scale and lime.
Tankless Water Heater Error Codes