Burnham ES2 ES24
The Burnham ES2 ES24 steps the cast-iron ES2 line to a fixed 105 MBH input: 89 MBH DOE heating capacity and a 77 MBH net AHRI rating at 85% AFUE, with a 5" draft hood for Category I chimney venting.
Key figures
- Max input
- 105 MBH
- Max CSA output
- —
- AFUE
- 85 %
- Min input
- —
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Burnham ES2 ES24 in practice
The ES24 is the second ES2 size at a fixed 105 MBH input, printing 89 MBH DOE heating capacity and a 77 MBH net AHRI water rating at 85% AFUE (ES2 I&O ratings table, Doc 103780-11). Like every ES2 it is a NON-condensing cast-iron boiler with a natural-draft draft hood — 5" on this size — vented Category I into an existing lined chimney as a chimney-replacement design.
It ships at 304 lb (231 lb empty), connects on 1-1/4" NPT supply/return with 1/2" NPT gas, and carries the IQ Boiler Control System with optional outdoor-reset and LWCO cards on natural or LP gas. The 50 psi MAWP rating ships with a 30 psi relief valve; supply water runs 130–220°F with a 110°F minimum return. A heat-loss calculation decides whether the load needs this size rather than the ES23; installation belongs with a licensed contractor.
Best suited to
- Homes whose chimney-vented load sits between the ES23 and ES25 sizes
- Replacements reusing an existing lined chimney with a 5" draft-hood connection
- Fixed-input cast-iron projects that do not need modulation
Applicability and support
- Model number
- ES24
- 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.
Specifications
Published specifications
Values as published by Burnham. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input | 105 MBH | Fixed input (no modulation) per the ES2 ratings table (Doc 103780-11); ratings apply to elevations up to 2,000 ft. |
| Output | ||
| DOE heating capacity | 89 MBH | Per the ES2 ratings table. |
| Net AHRI water rating | 77 MBH | Net AHRI water rating based on a piping and pickup allowance of 1.15, per the ES2 ratings table. |
| Efficiency | ||
| Efficiency (AFUE) | 85 % | 85% AFUE — a NON-condensing rating; the ES2 is a natural-draft cast-iron boiler, not a condensing design. |
| Domestic hot water | ||
| Domestic hot water | Heating-only boiler — domestic hot water comes from a separate indirect tank or water heater | |
| Venting and air | ||
| Venting | Category I natural draft — draft hood into an existing lined chimney (Type B/L gas vent); 5" draft hood | Non-condensing, natural-draft design: NOT a direct-vent or condensing boiler. Draft hood sizes per the ES2 I&O manual specifications. |
| Physical and connections | ||
| Shipping weight | 304 lb | Shipping weight 304 lb; empty (uncrated) boiler weight 231 lb, per the ES2 I&O manual weights and volume table. |
| Supply/return connections | 1-1/4" NPT | Supply and return both 1-1/4" NPT; relief valve 3/4" and drain 3/4" per the ES2 I&O manual. |
| Gas connection | 1/2" NPT | 1/2" NPT gas connection (ES23–ES26); ES27–ES29 use 3/4" NPT. |
| Electrical | ||
| Electrical | 120 VAC, 60 Hz, 1-phase, 15 A | Per the ES2 I&O manual specifications. |
| Operating limits and other | ||
| Maximum allowable working pressure (MAWP) | 50 psi | 50 psi MAWP; the boiler ships from the factory with a 30 psi safety relief valve. |
| Control | IQ Boiler Control System | IQ control with optional outdoor-reset and LWCO IQ option cards; the control flashes 'Err' + number for faults. |
Frequently asked questions
What are the ES24's ratings?
105 MBH fixed input, 89 MBH DOE heating capacity, a 77 MBH net AHRI water rating and 85% AFUE per the ES2 ratings table.
What vent size does the ES24 use?
A 5" draft hood for Category I natural-draft venting into an existing lined chimney.
Is the ES24 available on propane?
Yes — the ES2 runs on natural or LP gas per the official product page.
Questions about the Burnham ES2 ES24?
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
- U.S. Boiler Company — ES2 High Efficiency Gas-Fired Water Boiler product page · accessed September 8, 2026
- U.S. Boiler Company — Technical Literature (Alpine/ES2 I&O manual listings) · accessed September 8, 2026
- ES2 Gas Boiler — Installation, Operating & Service Instructions, Doc 103780-11 (PDF) · 103780-11 · accessed September 8, 2026
Facts checked September 8, 2026. Last updated September 8, 2026. Technical reviewer: not yet assigned.