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 GB142-45 kW was a different physical unit from the GB142-30 kW: the 45 kW moved to the longer 28 x 35.4 x 18.7 in cabinet at 143 lb with a higher 58 psi rating, firing 46,000 to 160,900 BTU/hr with 144,800 BTU/hr CSA output — roughly 50% more input than the 30 kW's 106,000 BTU/hr ceiling.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Buderus GB142-30 kW | Buderus GB142-45 kW |
|---|---|---|
| Rated thermal load, minimum (NG) | 32 MBH | 46 MBH |
| Rated thermal load, maximum (NG) | 106 MBH | 161 MBH |
| CSA output | 95 MBH | 145 MBH |
| Weight (without packaging) | 110 lb | 143 lb |
| Maximum flow temperature | 194 °F | 194 °F |
| Maximum operating overpressure of boiler | 43.5 psi | 58 psi |
| Heat exchanger heating circuit volume | 0.7 gal | 1 gal |
| Electrical power consumption, full load | 117 W | 64 W |
The GB142 line grew in two cabinet families: the 24/30 kW sizes used the 28 x 22 x 18.7 in, 110 lb unit rated 43.5 psi, while the 45/60 kW sizes used the longer 28 x 35.4 x 18.7 in (712 x 900 x 475 mm) cabinet at 143 lb and 58 psi (4 bar). The 45 kW is the first model that required the larger cabinet.
Capacity jumps with the cabinet: the 45 kW fires 46,000 to 160,900 BTU/hr natural-gas input with 144,800 BTU/hr CSA output, against the 30 kW's 31,800 to 106,000 BTU/hr and 95,400 BTU/hr CSA output. Interestingly its full-load electrical draw is lower at 64 W versus 117 W, per the IOM technical specifications.
Both are historical sizes from the discontinued GB142 family. Owners diagnosing an installed unit use the UBA 3 fault language of the 7214 9400 service instructions, and Bosch's CA FAQ still points GB142 owners to the service manual for 3L and 6A codes.
Bosch Thermotechnology
The Buderus GB142-30 kW was one of four GB142 condensing boiler sizes sold in Canada (24/30/45/60 kW). This size fired 31.8 to 106 MBH natural-gas input with 95 MBH CSA output; the model is now out of both the CA and US catalogs and is kept as a historical record with its manuals under the US discontinued-Buderus documentation library.
Bosch Thermotechnology
The Buderus GB142-45 kW was one of four GB142 condensing boiler sizes sold in Canada (24/30/45/60 kW). This size fired 46 to 160.9 MBH natural-gas input with 145 MBH CSA output; the model is now out of both the CA and US catalogs and is kept as a historical record with its manuals under the US discontinued-Buderus documentation library.
Yes — 143 lb versus 110 lb, in the longer 28 x 35.4 x 18.7 in cabinet. The 45 kW unit was also rated to a higher 58 psi maximum overpressure.
Per the IOM technical specifications the full-load electrical consumption is 64 W on the 45 kW and 117 W on the 30 kW — a published specification difference, not an error.
No — the sizes were separate physical units with different cabinets, weights and pressure ratings. Any replacement decision belongs to a licensed professional sizing a new boiler.
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 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.