Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Crown Boiler Co. · Series
The Cayman (CWI) is Crown's legacy cast-iron, natural-draft gas water boiler with an integrated tankless domestic water coil: nine sizes CWI103 through CWI380 (103–379 MBH input, net ratings 75–269 MBH) at 83.1–83.2% AFUE (the three largest print 81.4% thermal efficiency and are natural gas only), documented on the frozen crownboiler.com legacy pages and the hosted CWI manual.
Series facts
The specification table prints 83.1–83.2% AFUE on CWI103–CWI276; CWI311–CWI380 print 81.4% as thermal efficiency (footnote 2).
The Cayman (CWI Series) is Crown's legacy low-pressure cast-iron gas hot water boiler, listed in the frozen crownboiler.com 'Residential Gas' navigation and absent from the current Velocity Boiler Works menu. The CWI installation manual describes a Category I, draft-diverter-equipped appliance that must be vented by natural draft into a lined masonry or listed metal chimney, usable on forced or gravity hot water systems, with an integrated tankless heater for domestic hot water on CWI103–CWI276 (the tankless heater is optional equipment on CWI311–CWI380).
The specification table (Table 1) covers nine models: CWI103, CWI138, CWI172, CWI207, CWI241, CWI276, CWI311, CWI346 and CWI380. Inputs run 103 to 379 MBH over 4–12 cast-iron sections, heating capacities 86–309 MBH, AHRI net ratings 75–269 MBH (1.15 allowance), AFUE 83.1–83.2% on the six smaller models and 81.4% thermal efficiency on the three largest (natural gas only). Tankless heater ratings run 2.50 to 5.25 GPM (based on 40°F inlet water, 140°F outlet water and 190°F boiler water, 5-minute intermittent draws), and the table also prints per-model boiler dimensions and water volumes (10.0–27.6 gallons).
Because the tankless coil shares the boiler body, Boilers.ca records the models as water boilers with an integrated domestic coil (they are not combi boilers in the burner/DHW sense). The Cayman is legacy — productStatus 'discontinued' — and Boilers.ca documents all nine CWI models at model level from the hosted manual. No official Canadian-sales statement was found, so canadianStatus stays 'unknown'; gas, combustion and venting work belongs with a licensed contractor.
Highlights
Models
One canonical page per model with input, output and efficiency kept separate.
Crown Boiler Co.
The Crown Cayman CWI103 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 103 MBH input over 4 sections with 86 MBH heating capacity and a 75 MBH AHRI net rating at 83.1% AFUE.
Crown Boiler Co.
The Crown Cayman CWI138 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 138 MBH input over 5 sections with 115 MBH heating capacity and a 100 MBH AHRI net rating at 83.1% AFUE.
Crown Boiler Co.
The Crown Cayman CWI172 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 172 MBH input over 6 sections with 144 MBH heating capacity and a 125 MBH AHRI net rating at 83.2% AFUE.
Crown Boiler Co.
The Crown Cayman CWI207 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 207 MBH input over 7 sections with 173 MBH heating capacity and a 150 MBH AHRI net rating at 83.2% AFUE.
Crown Boiler Co.
The Crown Cayman CWI241 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 241 MBH input over 8 sections with 201 MBH heating capacity and a 175 MBH AHRI net rating at 83.2% AFUE.
Crown Boiler Co.
The Crown Cayman CWI276 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 276 MBH input over 9 sections with 230 MBH heating capacity and a 200 MBH AHRI net rating at 83.2% AFUE.
Crown Boiler Co.
The Crown Cayman CWI311 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 310 MBH input over 10 sections with 252 MBH heating capacity and a 219 MBH AHRI net rating at 81.4% thermal efficiency.
Crown Boiler Co.
The Crown Cayman CWI346 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 345 MBH input over 11 sections with 281 MBH heating capacity and a 244 MBH AHRI net rating at 81.4% thermal efficiency.
Crown Boiler Co.
The Crown Cayman CWI380 is a legacy cast-iron gas water boiler with an integrated tankless domestic coil: 379 MBH input over 12 sections with 309 MBH heating capacity and a 269 MBH AHRI net rating at 81.4% thermal efficiency.
| Specification | Crown Cayman CWI103 | Crown Cayman CWI138 | Crown Cayman CWI172 | Crown Cayman CWI207 | Crown Cayman CWI241 | Crown Cayman CWI276 | Crown Cayman CWI311 | Crown Cayman CWI346 | Crown Cayman CWI380 |
|---|---|---|---|---|---|---|---|---|---|
| input-min | — | — | — | — | — | — | — | — | — |
| Input | 103 MBH | 138 MBH | 172 MBH | 207 MBH | 241 MBH | 276 MBH | 310 MBH | 345 MBH | 379 MBH |
| output-max | — | — | — | — | — | — | — | — | — |
| Efficiency (AFUE) | 83.1 % | 83.1 % | 83.2 % | 83.2 % | 83.2 % | 83.2 % | — | — | — |
| turndown | — | — | — | — | — | — | — | — | — |
| vent-max-3 | — | — | — | — | — | — | — | — | — |
| vent-max-2 | — | — | — | — | — | — | — | — | — |
| weight | — | — | — | — | — | — | — | — | — |
Read the full comparison: Crown Cayman CWI103 vs CWI138 →
Read the full comparison: Crown Cayman CWI138 vs CWI172 →
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 Crown Boiler Co. boilers
No — the Cayman appears only in the frozen crownboiler.com legacy navigation and is absent from the current Velocity Boiler Works product menu, so Boilers.ca records productStatus 'discontinued'.
It is a cast-iron water boiler with an integrated tankless domestic hot water coil in the boiler body — not a burner-modulating combi. CWI103–CWI276 include the tankless heater; it is optional on CWI311–CWI380 per the manual.
No — the specification table restricts CWI311–CWI380 to natural gas only (not available for use with LP gas); CWI103–CWI276 are natural or LP gas.
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.