Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
Boilers.ca is a brand of ROMA Heating & Cooling · Licensed gas contractor LGA0202903
U.S. Boiler Company · Series
The ES2 is U.S. Boiler Company's cast-iron, chimney-vented gas water boiler at 85% AFUE, sold in seven sizes ES23 through ES29 covering 70–280 MBH input and 59–238 MBH DOE heating capacity with the IQ Control System, integrated draft diverter and outdoor-reset-ready IQ Option Panel.
Series facts
All seven ES2 rows print 85.0% AFUE in the ES2 Product Data Sheet ratings table.
The ES2 is U.S. Boiler Company's 85% AFUE cast-iron gas water boiler, listed under Gas-Fired Water Boilers on the official site and described there as an optimal replacement boiler for homes with existing chimneys. The product page positions it around an American-made cast-iron heat exchanger on a well-insulated heavy-duty steel base, industry-standard tapping locations, the IQ Boiler Control System, natural or LP gas operation and a lifetime limited warranty, with an optional energy-saving control package the page states can achieve a 15–20% reduction in fuel consumption 'according to most studies'.
The ES2 Product Data Sheet (Form HYDL09081) prints the complete ratings table: ES23 (70 MBH input, 59 MBH DOE heating capacity, 51 MBH net AHRI water, 4" vent, 254 lb), ES24 (105/89/77 MBH, 5", 301 lb), ES25 (140/119/103 MBH, 6", 353 lb), ES26 (175/149/130 MBH, 6", 405 lb), ES27 (210/178/155 MBH, 7", 464 lb), ES28 (245/208/181 MBH, 7", 514 lb) and ES29 (280/238/207 MBH, 8", 564 lb). All seven rows print 85.0% AFUE; ratings are certified to 2,000 feet and decrease three percent per 1,000 feet above that, with altitude kits required above 5,400 feet. Net AHRI water ratings use a 1.15 piping and pickup allowance, all boilers ship with a 30 PSI relief valve, and MAWP is 50 PSI.
Standard equipment includes the Intelligent Hydronic Control with a three-digit readout for status settings and errors, the IQ Option Panel accepting plug-and-play IQ Option Cards (outdoor reset with DHW priority, auto or manual reset low water cutoff, auto auxiliary high limit), a step-opening redundant gas valve, stainless-steel flue baffles, spark ignition with retry, a circulator, cast-iron section assembly, a resettable blocked vent switch and a boiler drain valve. Supply and return connections are 1-1/4" with water content from 2 to 8 gallons. Boilers.ca documents all seven sizes at model level from the data sheet and links the published I&O manual; no official Canadian-sales statement was found, so canadianStatus stays 'unknown'.
Highlights
Lifetime limited warranty per the ES2 Product Data Sheet standard equipment list.
Models
One canonical page per model with input, output and efficiency kept separate.
U.S. Boiler Company
The U.S. Boiler Company ES2 ES23 is the smallest ES2 size with 2 gallons of boiler water: 70 MBH input with 59 MBH DOE heating capacity and a 51 MBH net AHRI water rating at 85.0% AFUE, chimney vented in 4" on the IQ Control System.
U.S. Boiler Company
The U.S. Boiler Company ES2 ES24 is the second size, stepping up to a 5-inch vent: 105 MBH input with 89 MBH DOE heating capacity and a 77 MBH net AHRI water rating at 85.0% AFUE, chimney vented in 5" on the IQ Control System.
U.S. Boiler Company
The U.S. Boiler Company ES2 ES25 is the mid-size ES2 with a 6-inch vent: 140 MBH input with 119 MBH DOE heating capacity and a 103 MBH net AHRI water rating at 85.0% AFUE, chimney vented in 6" on the IQ Control System.
U.S. Boiler Company
The U.S. Boiler Company ES2 ES26 is the fourth size, sharing the 6-inch vent with the ES25: 175 MBH input with 149 MBH DOE heating capacity and a 130 MBH net AHRI water rating at 85.0% AFUE, chimney vented in 6" on the IQ Control System.
U.S. Boiler Company
The U.S. Boiler Company ES2 ES27 is the first size with a 3/4-inch gas valve and 7-inch vent: 210 MBH input with 178 MBH DOE heating capacity and a 155 MBH net AHRI water rating at 85.0% AFUE, chimney vented in 7" on the IQ Control System.
U.S. Boiler Company
The U.S. Boiler Company ES2 ES28 is the second-largest ES2 size: 245 MBH input with 208 MBH DOE heating capacity and a 181 MBH net AHRI water rating at 85.0% AFUE, chimney vented in 7" on the IQ Control System.
U.S. Boiler Company
The U.S. Boiler Company ES2 ES29 is the largest ES2 size with an 8-inch vent and 8 gallons of water: 280 MBH input with 238 MBH DOE heating capacity and a 207 MBH net AHRI water rating at 85.0% AFUE, chimney vented in 8" on the IQ Control System.
| Specification | U.S. Boiler Company ES2 ES23 | U.S. Boiler Company ES2 ES24 | U.S. Boiler Company ES2 ES25 | U.S. Boiler Company ES2 ES26 | U.S. Boiler Company ES2 ES27 | U.S. Boiler Company ES2 ES28 | U.S. Boiler Company ES2 ES29 |
|---|---|---|---|---|---|---|---|
| input-min | — | — | — | — | — | — | — |
| Input | 70 MBH | 105 MBH | 140 MBH | 175 MBH | 210 MBH | 245 MBH | 280 MBH |
| output-max | — | — | — | — | — | — | — |
| Efficiency (AFUE) | 85 % | 85 % | 85 % | 85 % | 85 % | 85 % | 85 % |
| turndown | — | — | — | — | — | — | — |
| vent-max-3 | — | — | — | — | — | — | — |
| vent-max-2 | — | — | — | — | — | — | — |
| Approx. shipping weight | 254 lb | 301 lb | 353 lb | 405 lb | 464 lb | 514 lb | 564 lb |
Read the full comparison: U.S. Boiler Company ES2 ES23 vs ES25 →
Read the full comparison: U.S. Boiler Company ES2 ES23 vs ES24 →
Read the full comparison: U.S. Boiler Company ES2 ES24 vs ES25 →
Read the full comparison: U.S. Boiler Company ES2 ES25 vs ES26 →
Error codes and alerts
No alerts documented for this series yet.
Manuals
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Services for U.S. Boiler Company boilers
No explicit Canadian-sales statement was found on usboiler.net when reviewed on September 9, 2026, so canadianStatus is recorded 'unknown'. The site's Rebates and Offers – Canada page is the only Canada-specific page found; confirm supply through a licensed distributor.
Seven sizes: ES23 through ES29, covering 70, 105, 140, 175, 210, 245 and 280 MBH input with DOE heating capacities of 59 to 238 MBH at 85.0% AFUE per the ES2 Product Data Sheet.
Yes — the ES2 is a chimney-vented (natural-draft) boiler with an integrated draft diverter, damper and connector, and the ratings table assigns a 4" to 8" vent by size. Homes without a chimney are the use case for the sibling power-vented PVG line.
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.