Burnham · SteamMax & Independence (gas steam)

Burnham Independence IN6I

The Burnham Independence IN6I is a current gas-fired cast-iron steam boiler: 175 MBH maximum input for 144 MBH heating capacity and a 108 MBH net AHRI steam rating (450 sq ft) at 82.1% AFUE, requiring a 6 in. x 15 ft (5 in. alternate) chimney and shipping at about 555 lb.

CurrentCanadian status unknown

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Key figures

Max input: 175 MBH
Max CSA output: —
AFUE: 82.1 %
Min input: —

Natural gasPropaneHeating-onlyresidential

Input is gas energy consumed; output is heat delivered. Never size from input alone.

Burnham Independence IN6I in practice

The Independence IN6I is one of the 10 sizes U.S. Boiler Company documents for the Independence gas-fired cast-iron steam line. Its official submittal row prints 175 MBH maximum input, 144 MBH heating capacity and a 108 MBH net AHRI steam rating covering 450 sq ft (1.333 piping and pickup allowance), at 82.1% AFUE, with a 6 in. x 15 ft (5 in. alternate) minimum chimney and a 555 lb approximate shipping weight.

The line is built with cast-iron push nipples, Honeywell operating controls, a vent damper and a rugged steel base under an insulated powder-coated steel jacket; the Independence PV variants are specifically configured as direct-vent products for homes with a damaged or irreparable chimney. The maximum working pressure is 15 PSI steam, and the product page prints a limited 10-year heat exchanger warranty plus a one-year manufacturer's parts warranty.

LP gas is available on the IN3–IN9 sizes per the submittal footnote and product page. No official Canadian-sales statement was found, so canadianStatus stays 'unknown', and gas, combustion and steam work belongs with a licensed contractor.

Best suited to

Steam systems needing about 450 sq ft of connected radiation
Residential steam replacements on a chimney-vented system
Installations comparing chimney-vented and Independence PV direct-vent configurations

Applicability and support

Model number: IN6I
Canadian availability: unknown
Production status: current
ROMA supplies: Confirmed at consultation
ROMA services: Confirmed at consultation
Warranty: Series terms

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.

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Specifications

Published specifications

Values as published by Burnham. Units are shown with every value; notes flag conflicting sources or missing figures.

Burnham Independence IN6I specifications
Specification	Value	Note
Input
Maximum input	175 MBH	Maximum input per the official Independence submittal/PDS ratings table (sea level to 2,000 ft; reduce 4% per 1,000 ft above sea level in the U.S.).
Output
Heating capacity	144 MBH	Heating capacity per the official Independence submittal ratings table.
Net AHRI steam rating	108 MBH	Net steam rating 108 MBH covering 450 sq ft, based on a piping and pickup allowance of 1.333 per the submittal.
Efficiency
Efficiency (AFUE)	82.1 %	AFUE per the official Independence submittal ratings table (up to 82%).
Venting and air
Minimum chimney requirement	6 in. x 15 ft (5 in. alternate)	Round chimney diameter x height measured from the top of the draft hood to the top of the chimney, per the submittal (15 ft minimum).
Physical and connections
Approximate shipping weight	555 lb	Approximate shipping weight per the official submittal.
Maximum working pressure	15 PSI steam	As printed on the official Independence submittal.
Operating limits and other
Fuel	Natural gas or LP gas (on select chimney-vented models)	Per the submittal footnote and product page: LP is available on the IN3–IN9 sizes.
Construction	Cast-iron sections with push nipples, Honeywell operating controls, vent damper and insulated steel jacket	Per the official Independence product page; the PV variants are configured as direct-vent products for homes with a damaged or irreparable chimney.
Warranty	Limited 10-year heat exchanger warranty plus a one-year manufacturer's parts warranty	As printed on the official Independence product page.

Manuals

Alerts documented for this model

None documented yet.

Services

Related parts & service

Frequently asked questions

What are the Independence IN6I's ratings?

175 MBH maximum input, 144 MBH heating capacity and a 108 MBH net AHRI steam rating (450 sq ft) at 82.1% AFUE per the official submittal.

What chimney does the IN6I need?

A 6 in. x 15 ft (5 in. alternate) round chimney, measured from the top of the draft hood to the top of the chimney (15 ft minimum) per the official submittal.

Can the IN6I run on propane?

Yes — LP gas is available on the IN3–IN9 sizes per the submittal footnote and product page.

Questions about the Burnham Independence IN6I?

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.

Call 778-909-5731 Request service

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Sources and verification

U.S. Boiler Company — Independence / Independence PV Gas Fired Cast Iron Steam Boilers (IN6I) · accessed September 9, 2026
Independence Product Data Sheet · accessed September 9, 2026
Independence Series Submittal Form · accessed September 9, 2026

Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.