190,000 BTU tankless gas water heater for homes with up to 3 bathrooms.
The ATI-310U for indoor installation is A. O. Smith's most popular and versatile tankless model. It features a maximum flow rate of 8 GPM, providing enough hot water for three showers in warm climates, or up to two showers in colder climates at the same time.
New, Improved Features
• Heat-resistant copper heat exchanger tubing
• Thicker heat exchanger drum
• Includes a pump control port
• Easy-Link System for up to 4 units
Specification highlights
• Set up for natural gas from factory, but field convertible from NG to LP with included gas conversion kit
• 190,000 BTUs
• Maximum flow rate of 8.0 GPM
• Non-condensing technology
• Ultra-Low NOx emissions (natural gas only). Complies with SCAQMD Rule 1146.2 for NOx emissions requirement of 14 ng/J or 20 ppm
• Complies with lead-free standards
• Built-in freeze protection
• Indoor models include factory-installed 120V power cord with plug
• Overheat cutoff fuse
• Inlet and outlet thermistors for constant temperature monitoring
• Can be used for radiant/hydronic/space heating as well as the usual running hot water (domestic hot water/DHW). See page 36 of the installation manual (download below).
Optional Accessories
• Horizontal, through-wall or vertical stainless steel venting kit
• Recess Box (for outdoor models)
• Pipe Cover
• Isolation Valve Kit
• Backflow Preventer
• Concentric Termination Kits
Certifications
Specifications
| Emission |
Ultra-Low NOx |
| Maximum BTUs |
190,000 |
Minimum BTUs
|
15,000 |
| Limited Heat Exchanger Warranty |
15 Years for residential installation
5 Years for commercial installation |
| Limited Parts Warranty |
5 Years |
| Water and Gas Connection Location |
Bottom |
| Water and Gas Connection Size |
3/4" male NPT |
| Heat Exchanger |
HRS35 Copper Alloy |
| Secondary Heat Exchanger |
Stainless Steel |
| Electrical power |
120V 60 Hz |
| Uniform Energy Factor (UEF) |
0.82 |
| ENERGY STAR qualified |
Yes |
| NSF Certification |
NSF/ANSI Standard 5 |
| CSA Certification |
Yes |
| CEC Compliant |
Yes |
| Technology |
Non-Condensing |
| Fresh air intake vent diameter |
3" |
| Exhaust vent diameter, material |
4", Category III Stainless Steel |
| Venting length |
60’ Max Length, 6 Elbows max
(90° elbows = 5’ equivalent length)
|
| Venting direction |
Horizontal or vertical
|
| Minimum water heating flow rate |
0.5 GPM initially, 0.4 GPM thereafter
|
|
|
| Type |
Space Saving |
| Height |
20.5" |
| Width |
13.75" |
| Depth |
9.5" for outdoor model
10.0" for indoor model |
| Product Weight |
39lbs/17.7kg |
| Shipping Weight |
44lbs |
|
Documentation
• Ultra-Low NOx Manual
• Spec Sheet
Frequently Asked Question ("FAQ")
Q1: What are the differences between the ATI-310-N (ATI-310-I-N) and the ATI-310U-N (ATI-310U-I-N)?
A1.1: The ATI-310U-N adds a 3" flue opening for fresh air for combustion intake. The ATI-310-N took in fresh air from the grill at the bottom front of the heater.
1.2. The ATI-310-U complies with Ultra Low NOx standards.
1.3. The water connections at the bottom of the heater are in different locations. The gas connection remains at the far right side.
