The MRCOOL Tankless Water Heater heats water only when a tap opens, firing a premixed gas burner of up to 199,000 BTU/h through stainless steel heat exchangers. MRCOOL rates it at about 8.45 GPM with a 45°F temperature rise, enough for up to four bathrooms running together. It comes as separate natural gas and liquid propane models.
It suits homes replacing a storage tank that runs out during busy mornings, and frees the floor space a tank takes up because it hangs on the wall. Installation is by a licensed plumbing or gas contractor. That is the MRCOOL Tankless Water Heater.
Features
Up to 199,000 BTU/h
The burner modulates between a 20,000 BTU/h minimum and 199,000 BTU/h, matching gas input to the hot water being drawn.
Rated Flow at Real Rises
MRCOOL rates about 11.12 GPM at a 35°F rise and 8.45 GPM at a 45°F rise. Heating starts from a minimum flow of 0.5 GPM.
Stainless Steel Heat Exchangers
Primary and secondary heat exchangers in lead-free 304 stainless steel resist corrosion and recover extra heat from the exhaust.
Low-NOx Premixed Burner
A premixed burner with a variable-speed BLDC combustion fan keeps the flame stable, and the unit meets SCAQMD standards.
Self-Adjusting Temperature Control
An electronic thermostatic control board regulates gas flow to hold the set point between 95°F and 140°F. It ships set to 120°F.
Built-In Freeze Protection
A ceramic heater switches on at 41°F to protect the internal waterways, as long as the unit stays powered.
Front Display Panel
The touch display shows the set temperature, error codes and operating data that help the owner and the service technician.
Specifications
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Heating Capacity: 199,000 BTU/h
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Voltage: 120V
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Frequency: 60 Hz
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Configuration: Indoor
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Ignition: Electric Ignition
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Wi-Fi: No
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ENERGY STAR: No
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CSA Listed: Yes
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Color: White
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Dimensions: 17.33"W x 11.03"D x 26.78"H
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Weight: 68.34 lbs
Natural gas
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Model: MHWH199NCNU
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Fuel: Natural Gas
Liquid propane
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Model: MHWH199NCLU
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Fuel: Propane
What's Included
- MRCOOL tankless gas water heater (natural gas or liquid propane model, per the variant chosen)
- Upper and lower wall-mounting brackets with a wall-mounting screw kit
- Gas shut-off valve
- Inlet valve assembly
- Bird screens (2)
- Flue gas flow limiting ring (for 3" vent pipe only)
- Fixing kit with O-rings, igniter gasket and sandpaper
- User's and installation manual
Installation
Professional installation required. Gas appliances must be installed by a licensed HVAC or gas contractor, following MRCOOL's installation manual, the fuel-gas and venting codes that apply where you live, and any permit requirements. MRCOOL's limited warranty applies only to units installed that way, and it does not cover installation labor.
Wall-mounted indoors on the supplied brackets, in a fire retardant location with at least 6" of clearance at the sides, 0" at the back and 12" at the top from combustible construction. Gas, cold water inlet and hot water outlet connections are 3/4" NPT and the condensate drain is 1/2" NPT. Venting is direct vent in 2" or 3" PVC, CPVC, approved polypropylene or concentric pipe.
Natural gas models need 3.5 to 10.5 in. WC supply pressure and propane models 8 to 13 in. WC. Water pressure must stay between 15 and 150 psi. The unit plugs into a 120V, 60Hz supply, and its altitude setting is adjusted at the control panel where needed.
Resources
Shipping, Returns & Warranty
Ships to addresses in the United States only. Shipping cost is calculated at checkout.
Inspect the packaging and the product before you sign. Note any damage or shortage on the delivery receipt, then email photos to support@mycleansupplies.com within 48 hours of delivery so the freight claim can be filed. Damage reported after 48 hours can't be claimed.
MRCOOL handles returns through the store you bought from, so your return comes to us. Unopened, unused MRCOOL equipment can be returned within 21 days of delivery with a return authorization from us. You pay the return shipping, and a restocking fee of up to 20% may be deducted along with payment processing fees. Opened, installed or used equipment and special-order items can't be returned.
MRCOOL warrants the tankless water heater to the original end user for 15 years on the heat exchanger, 5 years on all parts and 5 years of limited labor, with the first year of labor the installing company's responsibility. The warranty is non-transferable and applies only to units bought from an authorized dealer and installed to all applicable codes and licensing requirements. Full terms, registration steps and exclusions are in the MRCOOL warranty document under Resources.
Warranty claims. MRCOOL handles warranty claims directly through support.mrcool.com or (270) 366-0457. Some MRCOOL warranties cover the original purchaser only. Systems that aren't DIY need a valid installation invoice to open a claim.
About MRCOOL
MRCOOL designs heating, cooling and water-heating equipment from its home base in Hickory, Kentucky. The range runs from DIY ductless mini-splits, built around MRCOOL's patented pre-charged Quick Connect line sets, through contractor-installed mini-splits, central split systems, packaged units and gas furnaces, to HeatWise water heaters and CoolBlade HVLS fans for warehouses and shops.
The MRCOOL Tankless Water Heater is the gas-fired, on-demand member of MRCOOL's water heating range, sold as separate natural gas and liquid propane models. Homes that prefer a storage tank on electric power can look at MRCOOL's HeatWise electric tank water heaters instead. The tankless unit stands on its own and does not pair with MRCOOL's heating and cooling equipment.
