Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The Singular 4000 and 5200 are the same 80 lb wall-hung combi cabinet at 95.0% AFUE with the same 19,900 BTU/hr minimum input and venting to 60 ft in 2" or 150 ft in 3". The 5200 raises the DHW side from 155,000 to 199,000 BTU/hr (7.7 GPM versus 6.0 GPM at a 45 °F rise) and the space-heating input from 80,000 to 140,000 BTU/hr — the 5200 is the '199K BTU' model of the pair.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Bosch Singular 4000 | Bosch Singular 5200 |
|---|---|---|
| Space-heating input, minimum | 19.9 MBH | 19.9 MBH |
| Space-heating input, maximum | 80 MBH | 140 MBH |
| DHW input, maximum | 155 MBH | 199 MBH |
| DHW flow rate at 45 °F temperature rise | 6 gpm | 7.7 gpm |
| DHW flow rate at 67 °F temperature rise | 4 gpm | 5.2 gpm |
| Efficiency (AFUE) | 95 % | 95 % |
| Weight | 80 lb | 80 lb |
| Maximum vent length, 2" | 60 ft | 60 ft |
| Maximum vent length, 3" | 150 ft | 150 ft |
Both models are physically the same appliance: an 80 lb (per the engineering submittal sheet) wall-hung combi at 18.1 x 27.6 x 11.6 in, rated 95.0% AFUE on natural gas and propane, with stainless steel primary and secondary heat exchangers, 12-30 psi hydronic pressure, 3/4" NPT gas and 1" NPT heating connections, and venting to 60 ft in 2" or 150 ft in 3".
The two published differences are the firing ranges: space-heating input rises from 19,900-80,000 BTU/hr on the 4000 to 19,900-140,000 BTU/hr on the 5200, and DHW input from 19,900-155,000 to 19,900-199,000 BTU/hr. The spec table's DHW flow figures follow: 6.0 GPM against 7.7 GPM at a 45 °F rise (4.0 against 5.2 GPM at 67 °F).
Bosch's CA product page sells the pair as the 155K BTU and 199K BTU models — DHW-input figures — and estimates the 4000 runs two to three showers while the 5200 runs three showers plus a dishwasher, depending on inlet temperature. The minimum fire is identical at 19,900 BTU/hr, so in a low-load home both track mild weather the same way; the 5200 earns its place through the heat-loss calculation and the household's hot-water demand.
Bosch Thermotechnology
The Bosch Singular 4000 is the smaller of the two Canadian Singular combis: 19,900 to 80,000 BTU/hr space-heating input with DHW input to 155,000 BTU/hr (the '155K BTU' model), 95.0% AFUE, 6.0 GPM DHW flow at a 45 °F rise and stainless steel heat exchangers.
Bosch Thermotechnology
The Bosch Singular 5200 is the larger Canadian Singular combi: 19,900 to 140,000 BTU/hr space-heating input with DHW input to 199,000 BTU/hr (the '199K BTU' model), 95.0% AFUE, 7.7 GPM DHW flow at a 45 °F rise and up to 10:1 turndown.
Yes — same 18.1 x 27.6 x 11.6 in cabinet at about 80 lb, same 95.0% AFUE rating, same venting. The models differ only in firing range and DHW delivery.
7.7 GPM at a 45 °F rise against the 4000's 6.0 GPM (5.2 versus 4.0 GPM at 67 °F), per the IOM specification table.
Size from the heat-loss calculation and hot-water draw pattern: the 4000 covers most homes under an 80 MBH heating load, while the 5200 serves larger loads and heavier simultaneous draws without a bigger cabinet.
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.