Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The XFIIRE H7-400B adds 99 MBTUH of input and 94 MBTUH of output over the XFIIRE H7-300B on the same XFIIRE platform. The 300B is the only XFIIRE rated 96.5% — the 400B steps to 96% — while both share 2 in water connections, 4 in flue and air, and identical 411 lb shipping weight.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Raypak XFIIRE H7-300B | Raypak XFIIRE H7-400B |
|---|---|---|
| Input | 300 MBH | 399 MBH |
| Output | 289 MBH | 383 MBH |
| AHRI thermal efficiency | 96.5 % | 96 % |
| Turndown | 7:1 | 7:1 |
| Water connection | 2" NPT | 2" NPT |
| Flue outlet | 4 in | 4 in |
| Weight | 411 lb | 411 lb |
The H7-300B is rated 300 MBTUH input and 289 MBTUH output with 7:1 turndown; the H7-400B is rated 399 MBTUH input and 383 MBTUH output with 7:1 turndown. H7-300B is rated 96.5% and H7-400B 96% in the same efficiency column, so the larger size does not give up rated efficiency.
The 300B is the only XFIIRE rated 96.5% — the 400B steps to 96% — while both share 2 in water connections, 4 in flue and air, and identical 411 lb shipping weight. Maximum water flow rises from 38 gpm to 50 gpm, which is the main plant-side difference between the two sizes. Shipping or operating weight moves from 411 lb to 411 lb, which matters for rigging and floor loading.
Both sizes are documented in the same official Raypak submittal for the XFIIRE family, so the decision is a heat-loss and plant-layout question rather than a documentation difference: size to the calculated design-day load, then check flow, connection and venting dimensions against the submittal for the exact model.
Raypak
The Raypak XFIIRE H7-300B is a condensing commercial hydronic boiler rated 300 MBTUH input and 289 MBTUH output at 96.5% AHRI thermal efficiency, with 7:1 turndown, Category IV venting and 38 gpm maximum flow per submittal 241854.
Raypak
The Raypak XFIIRE H7-400B is a condensing commercial hydronic boiler rated 399 MBTUH input and 383 MBTUH output at 96% AHRI thermal efficiency, with 7:1 turndown, Category IV venting and 50 gpm maximum flow per submittal 241854.
The H7-300B at 96.5% AHRI thermal efficiency; the remaining sizes are rated 96% in the product page model data and submittal 241854.
Yes — the submittal prints the same dimensions (36.83 in by 45.34 in) and the same 411 lb shipping weight for both.
A consultation includes a heat-loss review so the size is right the first time.
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.