T-K4-OS Outdoor Tankless Water Heater
by Takagi

Add a tankless water heater to your home and enjoy never running out of hot water, always knowing that there will be enough hot water for every shower, bath, or other use. These units are designed for outdoor installation, but will still take up far less space without that bulky holding tank, and is powerful enough for up to three bathrooms. Let PlumbingSupply.com® be your source for Takagi products.
We also offer many more tankless water heaters by Takagi: T-KJr2-IN - T-KJr2-OS - T-K4-IN - T-D2-IN - T-D2-OS

Takagi T-K4-OS - Tankless Gas Water Heater for Outdoor Installations

image of T-K4-OS outdoor tankless water heater

Takagi's T-K4-OS is a small, yet powerful tankless water heater which is designed to handle heavy residential use (or light commercial needs), and be installed outside mounted on an exterior wall. As it is installed outside, you will see a huge savings on the costs for the stainless steel venting required for any indoor heaters. This water heater is only 20.5" x 13.8" x 8.5", so it will save space for those looking to maximize storage space in your home and garage.

Takagi is the leader in tankless water heaters and the T-K4 can significantly reduce your heating bills, again saving you money. It will take the place of your common 50 to 80 gallon, old tank-style, water heater - simplifying your maintenance. There's no pilot light to waste gas and the heater itself turns on (by electronic ignition) only when it senses a very low .75GPM (gallons per minute), so this will prevent hot water loss from leaky fixtures and faucets, but will be enough so you can get hot water to your bathroom sink for hand washing.

The bottom line is that the Takagi T-K4-OS can save costs and labor on install, free up space, reduce your monthly bills, and make your life more efficient. Of course with newer technology there is a need to learn it as well. Tankless water heaters will not stop heating the water until the flow stops. So if you decide to take an hour-long shower, you can, but keep in mind that you are no longer saving money on your energy bills, or water costs. Teaching your family how tankless water heaters work is key.

The Takagi T-K4-OS includes the TK-RE02 Temperature Remote Controller, which allows the default factory setting of 122°F output temperature from the water heater to be adjusted within the range of 99°F to 167°F, and it also works as a diagnostic tool that will give a concise error code whenever there is a problem with the unit.

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Takagi T-K4-OS Outdoor Tankless Water Heater with Remote Controller
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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. "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. "I've heard that some Takagi tankless water heaters cannot be installed in a few areas. Is that true?"
A. Yes, there are some counties that do not allow for the installation of a few Takagi tankless water heaters. For this reason, the person purchasing one of the following models is responsible for checking with their local code authorities prior to ordering: T-M32-NG, T-D2-IN-NG, T-D2-OS-NG, T-K4-IN-NG, T-K4-OS-NG, T-KJr-IN-NG, T-KJr-OS-NG. Here's a list (not complete) of some California counties that do not allow these water heaters to be installed: Sacramento, Yolo, Sonoma, San Joaquin, Napa, Marin, Solano, Contra Costa, San Francisco, San Mateo, Alameda, and Santa Clara. Again, this list is not complete, so it's up to the purchaser to check with local code authorities prior to ordering.

Q. "Why can't I install the T-K4-OS myself?"
A. Improper installation of the T-K4-OS 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 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.

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. "It sometimes drops below freezing where I live. Can I still install a Takagi tankless water heater outside?"
A. Takagi gas tankless water heaters are designed to be installed outdoors only in mild temperate climates. The factory-installed freeze protection device is rated for temperatures down to 5°F in a wind-free environment, so wind-chill factors must be taken into account when choosing whether or not to install a Takagi tankless water heater outdoors. If you are unsure if temperatures at your planned installation would work for an outdoor tankless water heater, we strongly recommend consulting with a trusted local professional.

Q. "What do I need to install these Takagi tankless water heaters outdoors?"
A. Outdoor-only Takagi tankless water heaters, such as the T-D2-OS or the T-K4-OS, require no additional venting components. Units that can be installed either indoors or outdoors, are designed to need only the addition of an outdoor vent cap or properly vented recess box in order to function in an outdoor installation. Please note that Takagi tankless water heaters, like most brands of water heaters, are designed to be installed outdoors only in mild temperate climates. As always, please consult with your installer or another trusted professional before installation.

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


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