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 RTGH-CS11i and RTGH-CSR11i are the same Rheem commercial condensing tankless water heater at identical ratings — 11,000–199,900 BTU/h, 11.2 GPM, 0.96 UEF. The only difference is the CSR's built-in recirculation pump, which adds 8.4 lb (86 lb vs 77.6 lb).
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Rheem RTGH-CS11i | Rheem RTGH-CSR11i |
|---|---|---|
| Input, maximum | 199,900 BTU/h | 199,900 BTU/h |
| Input, minimum | 11,000 BTU/h | 11,000 BTU/h |
| Uniform Energy Factor (UEF) | 0.96 UEF | 0.96 UEF |
| Flow at 35°F rise | 11.2 GPM | 11.2 GPM |
| Recirculation | No built-in recirculation pump | Built-in recirculation pump |
| Weight | 77.6 lb | 86 lb |
| Warranty | 8-year limited heat exchanger / 5-year limited parts / 1-year limited labor | 8-year limited heat exchanger / 5-year limited parts / 1-year limited labor |
Both models are documented in the same official brochure table and share the same platform: 199,900 BTU/h maximum input, 11,000 BTU/h minimum, 0.96 UEF, ENERGY STAR, 28-9/16 × 17-5/16 × 13-11/16 in cabinet, 2"/3" venting, manifold capability up to 32 units, and an 8-year heat-exchanger / 5-year parts / 1-year labor warranty.
The difference is domestic-hot-water delivery. The RTGH-CSR11i carries a built-in recirculation pump, with a maximum recirculation loop of 400 ft on 3/4" pipe or 100 ft on 1/2" pipe, so hot water arrives at the tap without a long wait. The RTGH-CS11i has no factory pump and weighs 77.6 lb against the CSR's 86 lb.
Neither is a boiler. For a commercial building, the choice is whether recirculated hot water is worth the pump and loop design; the heating capacity, gas supply, venting and manifold plan are identical between the two.
Rheem / Ruud (commercial)
The Rheem RTGH-CS11i is the base version of the IKONIC Commercial Condensing Tankless water heater — a commercial DHW-only appliance rated 11,000–199,900 BTU/h, 11.2 GPM and 0.96 UEF, not a boiler.
Rheem / Ruud (commercial)
The Rheem RTGH-CSR11i is the recirculation version of the IKONIC Commercial Condensing Tankless water heater — a commercial DHW-only appliance rated 11,000–199,900 BTU/h, 11.2 GPM and 0.96 UEF, not a boiler.
Yes. Both are rated 11,000–199,900 BTU/h, 11.2 GPM at a 35°F rise and 0.96 UEF; the difference is the recirculation pump.
The CSR weighs 86 lb against 77.6 lb for the CS, and it supports a recirculation loop up to 400 ft on 3/4" pipe or 100 ft on 1/2" pipe.
The base model has no factory pump; a recirculation loop can be added in the field, or the CSR model specified from the start. Design of the loop belongs with a licensed contractor.
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.