Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Hi Delta 652C adds 150 MBTUH of input and 126 MBTUH of output over the Hi Delta 502C on the same Hi Delta platform. The 652C adds 150 MBTUH of input over the 502C, moves the casing width from 50 in to 60-1/2 in and the flue from 6 in to 8 in.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Raypak Hi Delta 502C | Raypak Hi Delta 652C |
|---|---|---|
| Input | 500 MBH | 650 MBH |
| Output | 420 MBH | 546 MBH |
| AHRI thermal efficiency | 84 % | 84 % |
| Firing stages | 2-stage (H3) | 2-stage (H3) |
| Width (A) | 50 in | 60-1/2 in |
| Flue outlet | 6 in | 8 in |
| Weight | 545 lb | 590 lb |
The 502C is rated 500 MBTUH input and 420 MBTUH output with not printed turndown; the 652C is rated 650 MBTUH input and 546 MBTUH output with not printed turndown. Both models carry the same published efficiency figure, so capacity is the variable rather than efficiency.
The 652C adds 150 MBTUH of input over the 502C, moves the casing width from 50 in to 60-1/2 in and the flue from 6 in to 8 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 545 lb to 590 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 502C is a non-condensing copper finned-tube commercial hydronic boiler rated 500 MBTUH input and 420 MBTUH Type H output at 84% thermal efficiency, with 2-stage (H3) firing and a 6 in flue collar.
Raypak
The Raypak Hi Delta 652C is a non-condensing copper finned-tube commercial hydronic boiler rated 650 MBTUH input and 546 MBTUH Type H output at 84% thermal efficiency, with 2-stage (H3) firing and a 8 in flue collar.
The catalogue prints 420 MBTUH Type H output for the 502C and 546 MBTUH for the 652C, both at 84% thermal efficiency.
Yes — both use a 1-1/4 in NPT natural-gas connection per the 241877 submittal.
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.