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Comparison

Raypak Hi Delta SS HD201 vs HD251

Verdict in brief

The Raypak Hi Delta SS HD201 and Raypak Hi Delta SS HD251 are both non-condensing boilers in the Raypak Hi Delta SS line. The Raypak Hi Delta SS HD201 is rated 199 MBH input, 167 MBH output and 85% efficiency, and the Raypak Hi Delta SS HD251 is rated 250 MBH input, 210 MBH output and 85% efficiency. Raypak Hi Delta SS HD251 lists 51 MBH more input than Raypak Hi Delta SS HD201 (250 MBH against 199 MBH). Both list the same published efficiency of 85%. Raypak Hi Delta SS HD251 lists 25 lb more shipping weight than Raypak Hi Delta SS HD201 (225 lb against 200 lb).

Side by side

Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.

Comparison of Raypak Hi Delta SS HD201 and Raypak Hi Delta SS HD251
SpecificationRaypak Hi Delta SS HD201Raypak Hi Delta SS HD251
Input199 MBH250 MBH
Output167 MBH210 MBH
Weight200 lb225 lb
Height (B)12-1/2 in14-1/8 in
Width (A)25-1/16 in28-5/16 in
Venting categoryCategory ICategory I
FuelNatural gas or propaneNatural gas or propane
Thermal efficiency85 %85 %
Flue outlet5 in5 in
Maximum water flow44 GPM44 GPM
Electrical<5 A boiler draw, 120 V class<5 A boiler draw, 120 V class

What actually separates them

Published ratings: the Raypak Hi Delta SS HD201 is rated 199 MBH input, 167 MBH output and 85% efficiency; the Raypak Hi Delta SS HD251 is rated 250 MBH input, 210 MBH output and 85% efficiency. Raypak Hi Delta SS HD251 lists 51 MBH more input than Raypak Hi Delta SS HD201 (250 MBH against 199 MBH). Both list the same published efficiency of 85%.

Raypak Hi Delta SS HD251 lists 25 lb more shipping weight than Raypak Hi Delta SS HD201 (225 lb against 200 lb). The height differs: the Raypak Hi Delta SS HD201 lists 12-1/2 in, while the Raypak Hi Delta SS HD251 lists 14-1/8 in. The width differs: the Raypak Hi Delta SS HD201 lists 25-1/16 in, while the Raypak Hi Delta SS HD251 lists 28-5/16 in.

Both records print the same venting (Category I), fuel (Natural gas or propane), efficiency (85%) and flue outlet (5 in), per the cited sources.

CurrentCanadian status unknown
Input
—
Output (max)
167 MBH
AFUE
—

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.

Natural gasPropaneHeating-only
Specifications, manuals and service
CurrentCanadian status unknown
Input
—
Output (max)
210 MBH
AFUE
—

The Raypak Hi Delta SS HD251 is a compact non-condensing copper finned-tube commercial hydronic boiler rated 250 MBTUH input and 210 MBTUH output at 85% AFUE, with a 5 in flue and a 225 lb shipping weight per submittal 241922.

Natural gasPropaneHeating-only
Specifications, manuals and service

Frequently asked questions

Which of the two has the higher maximum input?

The Raypak Hi Delta SS HD251 lists 250 MBH, against 199 MBH on the Raypak Hi Delta SS HD201, per the cited documentation.

Which model is more efficient?

Both list the same efficiency of 85%.

How much heavier is the Raypak Hi Delta SS HD251?

It ships at 225 lb against 200 lb for the Raypak Hi Delta SS HD201, per the cited sources.

Not sure which one fits your home?

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.

Call 778-909-5731Request a consultation

Related

Sources and verification

Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.

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