The Rheem GT199XN Natural Gas Outdoor tankless hot water heater is our heavy duty unit meant for homes or businesses with more than 3 bathrooms, large-volume demands for hot water, or hot water circulating systems, you should choose the GT-199 heavy-duty series water heater.

Tankless gas commercial water heaters by Rheem-Ruud are designed to fill the need wherever hot water is required. Typical installations include: restaurants, hotels, laundry mats and multiple family housing.

Extensive manifold capability up to 20 of the commercial tankless units can be linked in a manifold configuration to meet the hot water needs of larger commercial applications. Energy saving design fully modulating burners are designed to use only as much gas as needed to satisfy the hot water demand. Space saving design compact dimensions simplify installations and fit tight spaces where larger water heaters may not. Remote control digital display thermostat displays temperature, verifies operation and shows maintenance and error codes for easy service. Exclusive combustion monitoring device monitors the combustion process and turns off the fuel supply if incomplete or inadequate combustion is detected. Exclusive film wrap overheat limiter instantly detects any overheating in the heat exchanger and shuts down the unit if unsafe temperature is detected. Built-in electric power burner provides installation flexibility, allowing for horizontal or vertical vent terminations up to 47-1/2 feet (indoor model).

Efficiency these models have been tested according to DOE test procedures, and exceed the thermal efficiency and standby loss requirements of ASHRAE Standard 90.1b-2001 (Part of the Federally mandated Energy Policy Act (EPact)). Also exceeds energy efficiency codes of all states including California Energy Commission (CEC).Safety and construction these products are design certified by CSA:

Please Note: ***If the water heater is installed anywhere other than a single family dwelling, such as a commercial application, or in any system in which the water is recirculated, the applicable warranty periods will be limited to three (3) years.

Temperature Increase / Gallons Per Minute

• 140ºF Rise at 2.4 gpm
• 130ºF Rise at 2.6 gpm
• 120ºF Rise at 2.8 gpm
• 110ºF Rise at 3.0 gpm
• 100ºF Rise at 3.3 gpm
• 90ºF Rise at 3.7 gpm
• 80ºF Rise at 4.1 gpm
• 77ºF Rise at 4.3 gpm
• 70ºF Rise at 4.7 gpm
• 60ºF Rise at 5.5 gpm
• 50ºF Rise at 6.6 gpm
• 45ºF Rise at 7.4 gpm
• 35ºF Rise at 8.5 gpm

Warning: This water heater is not suitable for use in manufactured (mobile) homes!

Height: 25 3/8"

Width: 14 7/8"

Depth: 11 1/8"

Primary Specifications

• Model: GT199XN
• 7.4 gpm at a 45ºF temperature rise (up to 8.5 gpm at 35ºF)
• Compact, space and energy saving design
• Built-in electric blower
• Temp Range: 100º - 180ºF
• Guardian OFW(TM) overheat film wrap
• Electronic ignition increases efficiency (no standing pilot light)
• Warranty: 3-year limited warranty on parts (10 years on heat exchanger.)
• Rheem GT199XN Heavy Duty Tankless Water Heater - Outdoor, Natural Gas
• Digital display shows temperature setting and maintenance codes
• Environmentally friendly Low NOx burner meets SCAQMD rule 1146 requirements
• Outdoor model (GT-199X) features freeze protection to -30ºF
• Includes Remote Control
• EZ-Link(TM) cable connects two like units to operate as one, doubling capacity
• Weight: 55 pounds
• Dimensions: 25 3/8"h x 14 7/8"w x 11 1/8"d

Technical Specifications:

• Outdoor Natural Gas
• 3/4" Water Connections
• 3/4" Gas Connection
• D.O.E. Annual Operating Cost- $167 Nat / $246 LP
• Temp Range: 100° - 180°F
• 19,000 - 199,000 BTU's is the
• 7.4 GPM Gas Water Heater
• 10-Year Limited Warranty on Heat Exchanger
• 3-Year Limited Warranty on Parts 
• Continuous hot water
• Energy saving design
• Compact, space saving design
• Intelligent electronic controls and sensors
• Self diagnostic program
• Digital display shows temperature setting and maintenance codes
• Exclusive sensing burner technology
• Exclusive film wrap overheat limiter
• Built-in electric blower
• Low NOx emissions meet SCAQMD rule 1146 requirements
• Remote Control is Included
• EZ-Link™ cable connects two like units to operate as one, doubling capacity – now available for high demand applications (cable not included)
• Dimensions: 25 3/8"H x 14 7/8"W x 11 1/8"D
• Weight: 55 lbs.
• Outdoor model (GT-199X) features freeze protection to -30°F
• Inlet Gas Pressure must not exceed 10.5” W.C. for natural gas (14” W.C. for LP propane)
• Unit does not include a pressure relief valve or the wiring to connect the remote thermostat
• Low NOx emissions meet SCAQMD rule 1146 requirements
• A remote control thermostat is included with all models (100 F - 140 F setpoint range) Requires 18 AWG, 2 conductor thermostat wire for remote control connection. Wire not included.

Minimum clearances for installation

• top 12"
• front 12"
• side 1/2"
• bottom 12"
• back 0"

Energy Requirements

• Ignition: Electric (120 V) - Outdoor units must be hardwired to a circuit breaker
• Power - 19,000 - 199,900
• Energy Factor: .82

***Our Recommended Accessories:

• BrassCraft 36" Long Stainless Steel Gas Connector w/ Pro Coating - Every gas water heater requires a gas connector and this model is our recommended top pick. We highly recommend this particular model for saving you time and money!  Also available in different lengths if required - simply call us toll free at 888-793-2665.
• Rheem Tankless Water Heater High Altitude Chip - Required if heater will be used above 3200 ft.
• RTG20040 - This cable connects two Rheem tankless gas water heaters to operate together as one unit for high demand applications.
• Rheem Recess Box For Outdoor Rheem Tankless Water Heaters - Provides extra protection for outdoor tankless models.
• Sioux Chief Gas Tankless Water Heater Connector Set - Required to connect all gas tankless water heaters to the corresponding water and gas lines. Includes pressure relief valve.
• Aqua Pure Hot Water Filter System - Recommended to prevent scale build up in all tankless water heaters.

You may download a product owner's manual below:

• Download Product Specification Sheet (PDF)

• Download Product Owner's Manual (PDF)

• Get Adobe Acrobat Reader

**Please note, Adobe Acrobat Reader is required to view pdf files

Model: AP430 AquaPure AP430 Hot Water System Protector In Stock: Usually Ships Same Business Day	$75.00 Add
Model: AP431 AquaPure AP431 Hot Water System Cartridge In Stock: Usually Ships Same Business Day	$39.00 Add
Model: GCNTKIT Gas Tankless Water Heater Connector Set - Value Kit In Stock: Usually Ships Same Business Day	$139.00 Add
Model: 6900101 Sioux Chief Gas Tankless Water Heater Connector Kit In Stock: Usually Ships Same Business Day	$89.95 Add

Temporarily Backordered

This item ships UPS or FedEx ground. Delivery times related to these ship methods are usually between 2 and 5 business days once the product leaves the warehouse. We will email you tracking information once the product leaves our warehouse. UPS or FedEx ground deliveries do not require a signature and may be left at the ship to location. All deliveries will occur Monday through Friday.

UPS or FedEx ground deliveries do not include a guaranteed delivery date. Should you require a specific delivery date or expedited shipping please add the item to the shopping cart and view the shipping options drop down box. If the product is eligible for expedited shipping the shipping options and pricing will be listed. Please contact our customer service department with any questions related to shipping. (800) 297-6076, M-F, 8am to 5pm CST.