Rinnai Demand Duo R Hybrid Water Heater, 199,000 BTU, 119 Gal, Natural Gas

The Rinnai CHS199100RECIN is an indoor Demand Duo R-Series hybrid that joins a non-condensing 199,000 BTU tankless engine, a 119-gallon tank and an integrated recovery pump. It targets restaurants, multifamily housing, fitness centers and light commercial tank change-outs on natural gas.

Firing rate modulates between 11,900 and 199,000 BTU/h, and the storage tank evens out sudden draws, so the burner cycles less and standby heat loss stays below that of an atmospheric tank. First-hour delivery reaches about 276 gallons at a 100°F rise, with a 0.81 UEF rating. The heat exchanger is copper; the tank is enamel lined, foam insulated and fitted with two magnesium anodes. Built-in safety covers flame failure, overheating, a blocked flue and freezing.

For retrofits, a 36 in. swivel gas flex and the electrical junction box come pre-installed, and in many change-outs the unit can tie into a 6 in. B-vent connector already on site (check the manual for venting). As a non-condensing design it produces no condensate to drain. The built-in controller operates the recovery pump, so no separate aquastat is required; set temperature runs from 120 to 180°F in 5°F increments, and Wi-Fi is an option for monitoring.

Highlights

• 199,000 BTU tankless engine, 11,900-199,000 BTU/h modulation

• 119 gal enamel-lined tank with dual magnesium anodes

• About 276 gal first-hour delivery at a 100°F rise

• 0.81 UEF, Low NOx (SCAQMD), AHRI and ANSI Z21.10.3 / CSA 4.3

• Can adapt to an existing 6 in. B-vent connector

• Thermostat range 120-180°F in 5°F steps

Specifications

In the box

• Integrated recovery pump and controller

• 36 in. pre-installed swivel gas flex

• Pre-installed electrical junction box

• Pressure-relief valve

• Brass drain valve

Good to know

• Gas-fired appliance: it must be installed, vented and commissioned by a qualified installer in line with local codes and the manufacturer's installation manual.