Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Hi Delta 402C adds 99 MBTUH of input and 83 MBTUH of output over the Hi Delta 302C on the same Hi Delta platform. The 302C and 402C are the two smallest 2-stage H3 sizes; the 402C adds 99 MBTUH of input and 83 MBTUH of output at the same 3/4 in gas connection, stepping the flue from 5 in to 6 in.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Raypak Hi Delta 302C | Raypak Hi Delta 402C |
|---|---|---|
| Input | 300 MBH | 399 MBH |
| Output | 252 MBH | 335 MBH |
| AHRI thermal efficiency | 84 % | 84 % |
| Firing stages | 2-stage (H3) | 2-stage (H3) |
| Width (A) | 36 in | 43 in |
| Flue outlet | 5 in | 6 in |
| Weight | 380 lb | 445 lb |
The 302C is rated 300 MBTUH input and 252 MBTUH output with not printed turndown; the 402C is rated 399 MBTUH input and 335 MBTUH output with not printed turndown. Both models carry the same published efficiency figure, so capacity is the variable rather than efficiency.
The 302C and 402C are the two smallest 2-stage H3 sizes; the 402C adds 99 MBTUH of input and 83 MBTUH of output at the same 3/4 in gas connection, stepping the flue from 5 in to 6 in. Both share the same 90 gpm maximum water flow, so the step up does not enlarge the pump or piping envelope. Shipping or operating weight moves from 380 lb to 445 lb, which matters for rigging and floor loading.
Both sizes are documented in the same official Raypak submittal for the Hi Delta 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 Hi Delta 302C is a non-condensing copper finned-tube commercial hydronic boiler rated 300 MBTUH input and 252 MBTUH Type H output at 84% thermal efficiency, with 2-stage (H3) firing and a 5 in flue collar.
Raypak
The Raypak Hi Delta 402C is a non-condensing copper finned-tube commercial hydronic boiler rated 399 MBTUH input and 335 MBTUH Type H output at 84% thermal efficiency, with 2-stage (H3) firing and a 6 in flue collar.
Both are 2-stage (H3) firing per the Hi Delta submittals; the MVB is Raypak's modulating vertical platform.
Yes — the submittals print natural-gas and propane ratings 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.