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 Hi Delta SS HD201 adds 49 MBTUH of input and 41 MBTUH of output over the Hi Delta SS HD151 on the same Hi Delta SS platform. The HD201 adds 49 MBTUH of input over the HD151, stepping the flue from 4 in to 5 in at the same 85% AFUE and 44 gpm maximum flow.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Raypak Hi Delta SS HD151 | Raypak Hi Delta SS HD201 |
|---|---|---|
| Input | 150 MBH | 199 MBH |
| Output | 126 MBH | 167 MBH |
| Thermal efficiency | 85 % | 85 % |
| Flue outlet | 4 in | 5 in |
| Weight | 175 lb | 200 lb |
| Maximum water flow | 44 GPM | 44 GPM |
The HD151 is rated 150 MBTUH input and 126 MBTUH output with not printed turndown; the HD201 is rated 199 MBTUH input and 167 MBTUH output with not printed turndown. Both models carry the same published efficiency figure, so capacity is the variable rather than efficiency.
The HD201 adds 49 MBTUH of input over the HD151, stepping the flue from 4 in to 5 in at the same 85% AFUE and 44 gpm maximum flow. Both share the same 44 gpm maximum water flow, so the step up does not enlarge the pump or piping envelope. Shipping or operating weight moves from 175 lb to 200 lb, which matters for rigging and floor loading.
Both sizes are documented in the same official Raypak submittal for the Hi Delta SS 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 SS HD151 is a compact non-condensing copper finned-tube commercial hydronic boiler rated 150 MBTUH input and 126 MBTUH output at 85% AFUE, with a 4 in flue and a 175 lb shipping weight per submittal 241922.
Raypak
The Raypak Hi Delta SS HD201 is a compact non-condensing copper finned-tube commercial hydronic boiler rated 199 MBTUH input and 167 MBTUH output at 85% AFUE, with a 5 in flue and a 200 lb shipping weight per submittal 241922.
Both are 85% AFUE per submittal 241922; the HD401 is the only size rated on thermal efficiency (84%).
Raypak prints a footprint under 6.9 ft for all Hi Delta SS models.
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.