Reliance tankless water heaters are high-efficiency and Energy Star gas-powered units that are designed for on-demand water heating in residential and light commercial applications. Check out the features to look for and popular models.
The Reliance manufacturer offers several sizes for you to buy, divided into three groups; standard, heaters with the low NOx gas emission and condensing, with an option for indoor and outdoor installation and use of natural gas or propane.
All the Reliance tankless models have an attractive and modern look; while its low weight construction and small size makes them perfect for installation on the wall and homes that lack in space.
Reliance tankless technology is based on Takagi technology, heating water on demand, and delivering hot water in endless supply.
All the Reliance tankless water heaters that are using conventional on-demand technology utilize one commercial-grade heat exchanger for long-lasting water heating, while the advanced electronics makes the process more accurate, reliable, and convenient. The energy factor (EF) of the standard tankless-type heaters is approximately 0.82, which is much higher than the EF found on conventional tank-type models.
So, even if you buy a non-condensing model which is cheaper than condensing, you will reduce your energy bill. Water heaters come from the 110, 310 and 510 series, and include the 15-year warranty. Indoor models offer two vent types, two-pipe and concentric system.
Models/Specs | BTU Min/ Max |
Efficiency EF |
Flow Rate Max (GPM) |
# of baths |
Remote / Controller |
TS-110-GI/E Indoor\Outdoor |
19,500 140,000 |
0.82 | 6.6 | 1-2 | Yes |
TS-310-GI/E Indoor\Outdoor |
11,000 190,000 |
0.82 | 8.0 | 2-3 | Yes |
TS-510-GI/E Indoor\Outdoor |
11,000 190,000 |
0.82 | 10.0 | 3+ | Yes |
Reliance tankless water heaters that are found in the low NOx group utilize the advanced modulating eco-friendly gas burner, designed to heat water efficiently and at the same time produce less greenhouse gases. The proper gas combustion, which is represented by the light blue and stable flame, can be seen and checked visually through the burner window located in the middle of the unit. Ultra-low NOx models are ideal for regions with strict emission rules. Customers have an option to buy an indoor or outdoor heater from 110, 310, and 510 series.
Models/Specs | BTU Min/ Max |
Efficiency EF |
Flow Rate Max (GPM) |
# of baths |
Remote / Controller |
TS-110-UI/E Indoor\Outdoor |
15,000 140,000 |
0.82 | 6.6 | 1-2 | Yes |
TS-310-UI/E Indoor\Outdoor |
15,000 190,000 |
0.82 | 8.0 | 2-3 | Yes |
TS-510-UI/E Indoor\Outdoor |
15,000 190,000 |
0.82 | 10.0 | 3+ | Yes |
Condensing units from Reliance are coming from 140, 240, 340 and 540 series using either natural gas or propane and for installation either indoor or outdoor. These are the most advanced water heaters that utilize two heat exchangers and produce hot water with the ultra-high efficiency of 0.95 for some extra savings. Another feature that makes them different from non-condensing models is the use of low-cost venting/exhaust system due to the low temperature of the products of combustion. Non-condensing models are using stainless steel vents. 540 models are coming with the recirculation pump for faster hot water delivery.
Models/Specs | BTU Min/ Max |
Efficiency EF |
Flow Rate Max (GPM) |
# of baths |
Remote / Controller |
TS-240-GIH/GEH Indoor\Outdoor |
13,000 160,000 |
0.95 | 6.6 | 1-2 | Yes |
TS-340-GIH/GEH Indoor\Outdoor |
13,000 180,000 |
0.95 | 8.0 | 2-3 | Yes |
TS-540-GIH/GEH Indoor\Outdoor |
13,000 199,000 |
0.95 | 10.0 | 3+ | Yes |
320 Indoor T-H2S-DV |
13,000 180,000 |
0.95 | 8.0 | 2-3 | Yes |
320 Outdoor T-H2S-OS |
13,000 180,000 |
0.95 | 8.0 | 2-3 | Yes |
520 Indoor T-H2-DV |
13,000 199,000 |
0.95 | 9.0 | 3+ | Yes |
520 Outdoor T-H2-OS |
13,000 199,000 |
0.95 | 9.0 | 3+ | Yes |
Reliance tankless water heaters with the small and medium capacities are coming from the 110, 310, 140, 240 and 340 series and have the water flow rate from 6.6 to 8 GPM, which provides a continuous supply of hot water to homes with one to three bathrooms. Models from 510 and 540 series have a higher water flow of 10 GPM and are recommended for homes with up to four showers (warmer regions).
The 510 and 540 models also use the Easy Link system, the communication cable, which allows connection of up to four of the same models and therefore increase the power and water flow. If none of the Reliance tankless water heaters can meet the demand for hot water of your home, an Easy Link system is the right solution. Models from 540 series can also use the Multi-link option to connect up to 20 units.
Condensing water heaters have an option to attach the recirculating pump to the pump control and work in four control modes. The benefits include faster hot water delivery, the higher recovery rate for storage tank applications, and greater energy savings.
All the units can use the temperature controller for easy temperature adjustment and diagnostics for faster troubleshooting. The temperature can be set in the range from 99 F to 167 F, or 185 F on some models, while the diagnostic feature provides an error code whenever there is a problem with the unit.
If the remote controller is not provided or connected to the heater, the temperature of the hot water can be adjusted by changing the dip switch setting on the computer board. There are four settings (from 113 F to 140 F) for 110 and 310 models and eight settings for the 510 model (from 104 F to 185 F).
A venting system is designed in a way, so the proper air supply is provided at all times without obstructions. Improperly used or damaged venting can lead to increased levels of carbon monoxide. By installing the direct vent kit, tankless water heaters will bring in all required combustible air from outside the home, while the termination is through the wall.
The air intake pipes can be made of various materials such as ABS, PVC, galvanized with a diameter of 3” while the exhaust system uses 4” Category III on non-condensing models. Pipes can run horizontally or vertically, and the maximum length is 50 ft.
Some indoor models use a dual-pipe system while other concentric venting, which makes the installation easier.
The outdoor models, which are for the outside installation only, do not use the venting pipe system and are recommended for homes located in areas with the mild temperature climates.
Related: Takagi water heaters
Choose a tankless water heater wisely. You don’t want to buy something that won’t meet the comfort level you would expect. Reliance tankless water heaters from the 110 and 140 series are the smallest, designed for use in homes with up to 2 bathrooms (warmer regions), while models from 510 and 540 are the most powerful and advanced, with the highest water flow rating, delivering enough hot water to up to 4 fixtures at the same time, or more when linked.