Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The discontinued G515/240 and G515/510 are oil/gas-fired cast-iron sectional boiler blocks with 87 psi maximum operating pressure and 248 °F maximum supply temperature. The /240 uses 7 sections with 685.8-818.9 MBH nominal output, 2,800 lb net weight and 68.2 gal water; the /510 uses 12 sections with 1,555.9-1,740.2 MBH, 4,542 lb and 115.7 gal.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Buderus G515/240 | Buderus G515/510 |
|---|---|---|
| Number of boiler sections | 7 | 12 |
| Nominal output, lower value | 685.8 MBH | 1,555.9 MBH |
| Nominal output, upper value | 818.9 MBH | 1,740.2 MBH |
| Combustion output, lower value | 735.7 MBH | 1,665.8 MBH |
| Combustion output, upper value | 886.1 MBH | 1,869.2 MBH |
| Weight, net | 2,800 lb | 4,542 lb |
| Boiler water content | 68.2 US gal | 115.7 US gal |
Both sizes share the Logano G515 design: Buderus cast-iron sections with Thermostream return-water mixing, forced-draft oil, gas or combination burner, 248 °F maximum permissible supply temperature and 87 psi maximum operating pressure. Minimum flow is none, per the manual's operating conditions.
The technical data table gives each size an output range: nominal output 685.8-818.9 MBH on the /240 rising to 1,555.9-1,740.2 MBH on the /510, with combustion output 735.7-886.1 to 1,665.8-1,869.2 MBH. Section count runs 7 to 12.
Physical rows: net weight 2,800 to 4,542 lb (packaging adds 6-8%) and boiler water content 68.2 to 115.7 US gal. The G515 is discontinued and documented in the US commercial-discontinued archive with installation/service and operating manuals plus the G315/G515/G615 brochure.
Bosch Thermotechnology
The Buderus G515/240 is a discontinued commercial cast-iron boiler block with 7 sections and a nominal output range of 685.8-818.9 MBH for oil, gas or combination burners.
Bosch Thermotechnology
The Buderus G515/510 is a discontinued commercial cast-iron boiler block with 12 sections and a nominal output range of 1,555.9-1,740.2 MBH for oil, gas or combination burners.
1,555.9 to 1,740.2 MBH depending on the firing rate, with 1,665.8-1,869.2 MBH combustion output, per the installation manual technical table.
No - the manual's operating conditions table lists 'none' for minimum flow rate, crediting the Thermostream design; the specified minimum boiler operating temperature must still be reached within 10 minutes.
No - it is a boiler block for oil, gas or combination burners; approved burners are listed by Bosch Thermotechnology Corp.
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.