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TK-4-IN Takagi Tankless Indoor Water Heater (Natural Gas)
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MANUALS (4)
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Product Highlights
Description
The Takagi brand has been discontinued by the manufacturer as of December 31, 2025. Suggested replacement units will be available on our website and replacement parts will continue to be available as supplies last. If you'd like any further assistance, please contact our customer service team.
Think Green, Save Green. Rebate and incentive programs provide cash-back to consumers for the purchase of appliances that meet certain energy efficiency standards. Most states are offering rebates in the $50 to $250 range. You can search for rebates in your area from here.
Note: Isolation valves are not included but are recommended for installation.
TK-REO2 Remote Control is included: TK-REO2 Remote Control
Released in 2010, the T-K4 improves upon many of the features from the T-K3. The T-K4 is one of Takagi's smaller tankless water heaters. At 13.8 inches wide and weighing only 38 pounds, its ultra-compact design allows it to be mounted on a wall.
Takagi's newest tankless water heater also features an energy factor of 0.82, so it is extremely efficient and environmentally friendly. Since tankless water heaters only burn gas when hot water is needed, installing this unit can help homeowners save up to 45% on their monthly gas bills.
Specifications:
- Capacity: 2 to 3 Bathrooms
- Flow Rate: Maximum 8.0 GPM
- Gas Inputs: 11,000 to 190,000 BTU per hour
- Energy Factor Rating: 0.82
- Inlet Gas Pressure: Min: 5.0" W.C. / Max 10.5" W.C.
- Dimensions: 20.3" H x 13.8" W x 8.5" D
- Direct Vent Capability
- Electric Ignition
Specs
| Application: | 2-3 Showers |
|---|---|
| Product Type: | Tankless Heater |
| Installation Type: | Indoor Only |
| Fuel Type: | Natural Gas |
| Height: | 20.3" |
| Energy Factor: | 0.82 |
| Width: | 13.8" |
| Vent Size: | 4" |
| Depth (Inches): | 8-1/2" 9-1/2" |
| Max Flow (GPM): | 8 |
| Inlet Gas Pressure: | 5.0-10.5"W.C. |
| Voltage: | 120v |
| Manifold Pressure: | 2.0-2.5"W.C. |
| Gas Input: | 11000-190000 BTU/h |
| Energy Star Rated: | No |
| Water Connection: | 3/4" |
| Venting Requirement: | Category III Stainless Steel |
| Gas Connection: | 3/4" |
| Vent Type: | Direct Vent Convertible |
| Temperature Range (F): | 99°F - 167°F |
| BTU (Max): | 190000 |
| BTU (Min): | 11000 |
| PSI Range: | 15-150 psi |
| Height (Inches): | 20.25" |
| Weight (lbs): | 38 lbs |
| Width (Inches): | 13-3/4" |
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Product Reviews
Yes!
nice unit for propane
Great heater
Quick shipping, excellent packaging
I will buy this same product again
Works GREAT and Quick delivery
Great heater and awesome service!
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Great product, but do your research
This is my second TK-4-IN.
Takagi has been great to us.
Product Q&A
31 QuestionsQ: do these require single wall or double wall pipe for venting?
Asked by capone 11 years ago
Add your answer
Verified Reply- Supplyhouse StaffUnfortunately this is not a simple answer, as venting is governed by local codes. Please have the installer confirm what is required by code.
Q: i have a tankless water heater now but it does not require any elec does this one
Asked by happy 11 years ago
Add your answer
Verified Reply- SupplyHouse StaffYes, this tankless water heater requires a properly grounded 120 Volt AC power connection to operate.
Q: Does the unit need to be nearest the sinks, shower and washing machine for proper operation while simultaneous being able to provide enough hot water for the radiant floor heat ? Will a zone valve with thermostat need to be added in order to effect floor heating separately ? In other words how is the radiant floor heat separated from the domestic hot water so that when using domestic water your not heating up the house ? Additionally the residence is only 500 square foot micro home... Will this unit be to large or do I need the Jr model ?
Asked by Jimbo 11 years ago
Add your answer
Verified Reply- Supplyhouse Staffdepends on your system and water usage, yes plus a mixing valve, see the Link below. http://s3.supplyhouse.com/manuals/1289421060124/41440_PROD_FILE.pdf
Q: Can this unit be vented with PVC?
Asked by Mike 11 years ago
Add your answer
Verified Reply- Supplyhouse Staffno, it can not
Q: DOES THE UNIT HAVE IT.S OWN PUMP
Asked by RON 12 years ago
Add your answer
Verified Reply- SupplyHouse StaffNo, the unit does not include a circulator.
Q: I bought a Takagi TK4in lp and the supply and delivery plumbing is 3/4 inch but my hot water feed lines to the showers is 1/2. Will it work?
Asked by joe 12 years ago
Add your answer
Verified Reply- Supplyhouse Staffyes it will, you will to reduce after the connection off the unit, it will effect the flow rate.
Q: I plan to replace my 50 gallon natural gas water heater with a tankless when it dies. Is it OK to use the existing exhaust vent through the roof? This would be best since I have just had new shingles installed and the roof is good for the next 20 years. Also: Is and exterior intake vent required for these water heaters?
Asked by Sterling 12 years ago
Add your answer
Verified Reply- SupplyHouse StaffMost likely no, the TK-4 requires category III stainless steel venting, and it is unlikely that your current venting is made of this material.
Q: Will any of the Takagi units work for an in floor radiant heat system for 1400 sq ft home? Home is in Albuquerque, New Mexico -5000 ft altitude.
Asked by Shaleen 14 years ago
Add your answer
Verified Reply- PexSupply StaffAny of the Takagi units (even the T-KJr.) should be fine for a house that size. Just make sure to use primary/secondary piping and make the proper dipswitch adjustments for high-altitude installations.
yes they will, I heat a 1400 sq ft house in chicago with one takagi jr.
Q: Does this unit have any problems with the "water sandwich" effect, with short bursts of cold water in the middle of hot water flow, especially in showers?
Asked by Joe 14 years ago
Add your answer
I have 3 of these heaters and have never experienced what you described. You can get some water cooling if someone else opens a hot faucet while you are showering. It does not go cold just not as hot.
Not at all. this is the 4th tankless water heater I have owned and by far the best. The temp is super consistent and the delivery is much quicker than the Bosch I owned previously. It has never failed to light, not once. Would recommend without reservation!
I have never had any issues with the water sandwich effect.
No not at all I have installed 4 this year no complaints Sent from my iPhone
No! This is not problem with the unit I have. This can happen if you have poor water pressure at times of showering.
no unit always has hot water
Q: I am purchasing the TK-4 IN Propane, and am wanting to know more about the venting system. I am looking at using the Z-Vent self sealing bent parts from your site. I see the direct vent conversion part, am I right in assuming that when you chose to use it then you add the "2nd" pipe (thus a 3nd opening) and another hole for intake? If I use the sealed Z-Vent parts, and do not 'convert it", then I wont need a second opening or pipe?
Asked by blmranch 14 years ago
Add your answer
Yes. Just direct vent the exhaust ( 1 ) penetration 99.9 % of installs will do it. Sent from my iPhone
Hello bimranch, I have install four TK-4 heaters. You need to use stainless pipe for the 4" discharge. This is required by manufactor. Z-vent is the brand I have used and the product is easy to install. On the intake side, the conversation kit covers the front intake and provide a 3" intake on the top of the unit. This piping does not have to be stainless steel pipe. If you do not use the conversion kit the unit takes air from the front of the unit and know other piping is required. Hope this helps, jim
Direct vent should be used when you do not have enough fresh air (like a trailer) or in a dust room like a work shop. just stick with the Z-vent and you will be fine.
it only takes two pipes( one for intake ,one for exhaust) unless you use the concentric(sic) pipe then it uses one pipe for both intake and venting. i was able to download the installation manual . it shows all installation methods. ( if you do not use the direct vent conversion there is only the one exhaust pipe and intake air is drawn from the mechanical room.