Product overview
MRCOOL 199,000 BTU Natural Gas Tankless Water Heater
The MRCOOL MHWH199NCNU delivers continuous, on-demand hot water for whole-home use in a compact indoor design. Its lead-free stainless steel heat exchanger, premixed low-NOx burner, variable-speed fan, touchscreen controls, self-adapting temperature regulation, and built-in freeze protection are engineered for efficient, dependable performance.
Key features
- 199,000 BTU/h maximum input for high-demand residential hot water
- Supplies up to four bathrooms and multiple appliances, depending on inlet-water temperature and simultaneous demand
- Up to 11.1 GPM at a 34°F temperature rise and 8.5 GPM at a 45°F rise
- 0.95 Uniform Energy Factor (UEF) and ENERGY STAR certified
- Lead-free primary and secondary stainless steel heat exchanger
- Electronic thermostatic PCB and EDM BLDC variable-speed fan
- Premixed anti-flashback burner with reduced NOx emissions
- Large touchscreen display for operation, diagnostics, and maintenance
- Category IV power direct venting using 2-inch, 3-inch, or concentric venting
Hot water performance
| Temperature rise | Flow rate |
|---|---|
| 34°F | 11.1 GPM |
| 45°F | 8.5 GPM |
| 67°F | 5.7 GPM |
Actual flow varies with inlet-water temperature, set temperature, gas supply, water pressure, and simultaneous demand.
Specifications
| Brand | MRCOOL |
|---|---|
| Model / MPN | MHWH199NCNU |
| UPC | 810035930346 |
| Fuel type | Natural Gas |
| Installation | Indoor, wall mounted; qualified professional required |
| Maximum input | 199,000 BTU/h (58.3 kW) |
| Minimum input | 20,000 BTU/h (5.9 kW) |
| Uniform Energy Factor | 0.95 |
| Heat exchanger | Lead-free primary and secondary stainless steel |
| Temperature setting range | 95°F–140°F |
| Factory temperature setting | 120°F |
| Minimum actuation flow | 0.5 GPM |
| Inlet gas pressure | 3.5–10.5 in. WC |
| Manifold pressure | -0.9 in. WC |
| Water pressure | 15–150 PSI |
| Gas connection | 3/4-inch NPT |
| Water connections | 3/4-inch NPT inlet and outlet |
| Condensate drain | 1/2-inch NPT |
| Venting | 2-inch or 3-inch, or concentric PVC, CPVC, or approved polypropylene |
| Venting type | Category IV power direct vent |
| Ignition | Direct electric ignition |
| Power supply | 120V AC, 60 Hz |
| Power consumption | 150 W, plus 114 W while the freeze-protection module operates |
| Maximum current | 1.3 A |
| Wi-Fi / app compatibility | No |
| Certifications | CSA listed/certified; ENERGY STAR certified |
| Color | White |
| Product dimensions | 26.8 H × 17.3 W × 10.6 D in. (connectors excluded) |
| Net weight | 66.1 lb |
| Shipping dimensions | 33.22 H × 20.27 W × 13.74 D in. |
| Shipping weight | 74 lb |
| Proposition 65 warning | Yes |
What’s included
- MRCOOL MHWH199NCNU natural gas tankless water heater
- Gas shutoff valve
- Upper and lower wall-mount brackets and mounting screw kit
- Two bird screens and 3-inch flue-flow limiting ring
- Inlet valve assembly, O-rings, igniter gasket, sandpaper, and fixing kit
- Installation and operation documentation
Required installation items such as the pressure-relief valve, service valves, flush kit, venting, and job-site materials are not stated as supplied in the current manual. Confirm the complete installation package with your licensed installer.
Warranty
Manufacturer coverage includes a 15-year limited heat-exchanger warranty, 5-year parts warranty, and 5-year limited labor warranty for the original end user, subject to the purchase, installation, registration, and other terms in the warranty certificate.
Product documents
- Installation & Operation Manual — English (PDF)
- Installation Manual — French (PDF)
- Product Brochure & Specification Sheet (PDF)
- Limited Warranty (PDF)
- ENERGY STAR Product Data (PDF)
Professional installation is required. Confirm local gas, venting, electrical, condensate, plumbing, and code requirements before purchase. This appliance is factory configured for natural gas and must not be field converted. The current manufacturer manual and warranty terms control if specifications change.
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