Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
Boilers.ca is a brand of ROMA Heating & Cooling · Licensed gas contractor LGA0202903
Comparison
Verdict in brief
The MVB H7-754A adds 250 MBTUH of input and 210 MBTUH of output over the MVB H7-504A on the same MVB Category I & III platform. The 504A and 754A share 2 in water connections, a 1 in gas connection and 100 gpm maximum flow, so the 250 MBTUH step needs no piping change; the flue grows from 8 in to 10 in.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Raypak MVB H7-504A | Raypak MVB H7-754A |
|---|---|---|
| Input | 500 MBH | 750 MBH |
| Output | 420 MBH | 630 MBH |
| AHRI thermal efficiency | 84 % | 84 % |
| Turndown | 1.7:1 | 1.7:1 |
| Water connection | 2" NPT | 2" NPT |
| Flue outlet | 8 in | 10 in |
| Weight | 600 lb | 670 lb |
The H7-504A is rated 500 MBTUH input and 420 MBTUH output with 1.7:1 turndown; the H7-754A is rated 750 MBTUH input and 630 MBTUH output with 1.7:1 turndown. Both models carry the same published efficiency figure, so capacity is the variable rather than efficiency.
The 504A and 754A share 2 in water connections, a 1 in gas connection and 100 gpm maximum flow, so the 250 MBTUH step needs no piping change; the flue grows from 8 in to 10 in. Both share the same 100 gpm maximum water flow, so the step up does not enlarge the pump or piping envelope. Shipping or operating weight moves from 600 lb to 670 lb, which matters for rigging and floor loading.
Both sizes are documented in the same official Raypak submittal for the MVB Category I & III 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 MVB H7-504A is a non-condensing modulating vertical commercial hydronic boiler rated 500 MBTUH input and 420 MBTUH output at 84% thermal efficiency, with Category I & III venting and a 8 in flue.
Raypak
The Raypak MVB H7-754A is a non-condensing modulating vertical commercial hydronic boiler rated 750 MBTUH input and 630 MBTUH output at 84% thermal efficiency, with Category I & III venting and a 10 in flue.
No — these are the non-condensing members of the MVB platform, rated 84% thermal efficiency and vented as Category I or III.
The product page model data prints 1.7:1 turndown for both the 504A and 754A.
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.