TK-510U-I Indoor Tankless Water Heaters
by Takagi

If you want a tankless water heater for your light commercial use, or want something a little more robust for your home, you've found it! The Takagi TK-510U-I Indoor Tankless Water Heater is powerful enough for up to three bathrooms, and can also handle the use in a salon or even a restaurant, making this a versatile unit that will fit in a compact space.
We also offer many more tankless water heaters by Takagi:
TK-110U-I (indoor) - TK-110U-E (outdoor) - TK-310U-I (indoor) - TK-310U-E (outdoor) - TK-510U-E (outdoor)

Takagi TK-510U-I - Tankless Gas Water Heater for Indoor Installations

image of TK-510U-I indoor tankless water heater
  • Factory set for Natural gas and comes with an LPG conversion kit for conversion in the field
  • 19,500 up to 199,000 BTU input
  • Tankless technology provides hot water when you need it - does not waste energy heating water when you don't need it
  • This compact but powerful indoor installation unit is ideal for homes with three bathrooms, as well as light commercial use such as restaurants or salons
  • This unit heats water flows ranging from 0.50 to 10 gallons per minute, and can be linked to up to 4 other TK-510U-I units to provide up to 40 gallons per minute, depending on temperature rise
  • Includes Built-In Temperature Controller, which allows the default factory setting of 120°F output temperature from the water heater to be adjusted within the range of 100°F to 160°F, and it also works as a diagnostic tool that will give a concise error code whenever there is a problem with the unit
  • With compact dimensions this hot water heater can be installed nearly anywhere, often allowing for installation far closer to the main point of use than traditional tank-type heaters
  • Vent with Category III stainless steel or easily convert to direct vent to draw air from the outdoors; no air is used from the indoor installation location, making them ideal for tight spaces or where indoor air is unsuitable for combustion
  • Computer-controlled burners and electronic ignition use only the amount of gas required according to the demand, which significantly increases this unit's efficiency and can help decrease your gas bill
  • View more detailed specifications
  • View flow rate and pressure loss information
  • Looking to install this tankless water heater outdoors? Click here
Takagi TK-510U-I Indoor Tankless Gas Water Heater = Temporarily Unavailable
Factory Equipped for Natural Gas with Included Liquid Propane Conversion Kit
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Please note: Some areas do not allow installation of a few of these water heaters. Read more

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Please note: For potential safety reasons, we do not recommend using PVC to vent gas tankless water heaters. For the best results, we recommend using Category 3 stainless steel gas vent pipe for all gas tankless water heaters.



Frequently Asked Questions

Q. "What type of vent do these tankless water heaters require?"
A. These tankless water heaters require Category III stainless steel vent only.

Q. "If these units don't have a tank, how do they know when to turn on?"
A. These tankless water heaters have a flow switch built into them. When you turn on the hot side of a faucet the water begins moving. Once the water is traveling at minimum flow rate for the heater, the flow switch will turn on the gas.

Q. "Why can't I install the TK-510U-I myself?"
A. Improper installation of the TK-510U-I could create carbon monoxide gas and other dangerous gases. Installation of this unit by persons other than professionally trained technicians voids the warranty.

Q. "What's the difference between a conventional flue and a direct vent?"
A. A conventional flue is what most people are familiar with. It typically consists of a double-wall flue pipe going from the top of the heater through the roof, venting outside. The fixture draws its combustion air from the space around it (utility room, garage, hallway, etc.). A direct-vent unit vents and draws its combustion air through a specially designed pipe from the outside via an adjacent wall.

Q. "I live in an area where it freezes, what can I do to protect the heater from freezing?"
A. We recommend you use the Nova Vent 9007996005 backflow preventer kit to keep cold air from entering the vent and causing the heat exchanger to freeze.

Q. "Can I use PVC to vent this tankless water heater?"
A. No. The temperature of the exhaust is too high to safely use PVC as venting material. We never recommend PVC as venting even where the ideal exhaust temperatures would technically allow it due to a much higher incident of dangerous issues and failure associated with PVC venting on poorly-maintained gas tankless water heaters.

Q. "Your products specify the 'temp. rise' based on the GPM flow; what do you mean by this?"
A. Temperature rise is the amount the heater raises the temperature of the incoming water, based on the flow rate shown of that water.

Q. "What's the first hour rating of this water heater?"
A. Traditional tank water heaters have a first hour rating which is determined by the amount of hot water the heater can produce in an hour when starting with a full tank of hot water. As tankless water heaters do not start with a tank of hot water, they don't really have a first hour rating the same way a tank water heater does. Instead, tankless water heaters have a gallons per hour rating, which is determined by how many gallons per hour the tankless water heater can produce when raising the incoming water temperature a specified amount.

All Takagi tankless water heaters must be installed by a licensed professional.


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