T-K4 - 190,000 BTU Natural Gas Outdoor Non-Condensing


T-K4-OS-N (Outdoor)

The compact T-K4 is a fully modulating, gas fired, tankless water heater perfect for residential applications. The T-K4 can produce enough hot water for up to three bathrooms in warmer climates.

Number of showers this unit can handle, depending on ground water temperature.

Warmer Climates

Cooler Climates


The T-K4 supplies hot water to domestic hot water systems (directly or indirectly) which can be used with storage tanks, recirculation systems, hydronic heating systems, radiant floor systems, and/or domestic & heating applications.

  • 15-year limited heat exchanger, 5 yrs limited parts Residential use
  • Includes a remote control as a standard feature
  • Safety features include freeze, overheat, surge protection, and troubleshooting diagnostic codes

Tk 4 No -e

Tech Specs

Emissions: Low NOx
Maximum BTUs: 190,000
Minimum BTUs: 0
Water Connection Location: Bottom
Water Connection: 3/4"
Flow Rate: 8.00
Heat Exchanger: Copper
Voltage: AC 120V
UEF: 0.80
ENERGY STAR® Qualified: No
LEED Rating: 0.0
Remote Control: Yes
Technology: Non-Condensing
Multilink: No

Dimensions & Venting

Height: 20.25"
Width: 13.75"
Depth: 9.50"
Product Weight: 43 lbs.
Vent Type: Direct Vent
Vent Size: 4"


This model is intended for Outdoor installation, no venting is required.

Please check the Product Manual for information on proper installation.


Recess Box

The 9007674005 Recess Box completely houses the tankless hot water unit and allows it to be completely recessed into a wall for a smooth, almost seamless look. It is just over 14 inches wide so it easily fits in-between the studs.

For Use with the following models:

T-KJr2-OS, T-KJr2U-OS, T-K4-OS, T-K4U-OS, T-D2-OS, T-D2U-OS

Pipe Cover

The 9007670005 Pipe Cover protects the plumbing pipes to the water heater from unexpected adjustments. This pipe cover is fixed to the bottom of the water heater, which hides the plumbing and improves the visual aspects of the whole installation for the water heater.

For Use with the following models:

T-KJr2U-IN, T-KJr2U-OS, T-K4-IN, T-K4-OS, T-K4U-IN, T-K4U-OS, T-D2-IN, T-D2-OS, T-D2U-IN, T-D2U-OS

Remote Temperature Controller

The 9007666005 Remote Temperature Controller (TK-RE02) allows the output temperature to be adjusted beyond the factory settings, and works as a diagnostic tool for error codes.
(Not compatible with the Ultra-Low NOx models)

For Use with the following models:

T-KJr2-IN, T-KJr2-OS,  T-K4-IN, T-K4-OS

Lead Free Isolation Valves & Pressure Relief Valve

The 9007604005 Lead Free Isolation Valves & Pressure Relief Valves are used to isolate a unit for service. The Pressure Relief Valve is to help protect the unit and release if the pressure in the tankless water heater or hot water system exceeds 150 psi and up to 200,000 BTUs. For 3/4" water lines. (1953 Compliant)

For Use with the following models:

TK-110C-NI, TK-310C-NI, TK-510C-NI, T-KJr2/U, T-K4/U, T-D2/U, T-H3M, T-H3J, T-H3S, T-H3


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