Features & Benefits

  • The tighter the commercial retrofit, the more you will appreciate how the Universal’s compact size and multiple water connections simplify low NOx installations.
  • Choose from 80% thermal efficiency models that range from 125,000-399,900 BTU/h and have maximum temperature setting of 180 degrees Fahrenheit.

Space Saver Design

  • The short heights and narrow jacket diameters, plus the top, front and rear water inlets/outlets offer the ultimate in installation flexibility.

System Sentinel™ LED Diagnostic System

  • Our exclusive diagnostic system, with glowing LED lights, verifies system operation sequence by sequence. 

Patented Technology

  • Universal’s proprietary steel formulation, patented multi-flue design, combined with two coats of porcelain enamel, results in a superior heat exchanger design.

Low NOx Burner

  • The power assist burner design incorporates stainless steel multi-port burner tubes for long term low NOx performance, less than 40 ng/J.
  • A sight glass allows for burner observation.
  • A blower guard provides protection against potential post-installation damage.
  • The entire design is removable and it is highly resistant to the effects of negative air pressure common in modern commercial buildings.

Low Profile Automatic Flue Damper

  • Low profile damper minimizes overall product height.
  • Heavy duty vent hood supports are designed to withstand the rigors of installation.

Full-port, Full-flow Drain Valve

  • Factory installed brass drain valve allows for faster draining and servicing.

Direct Spark-to-Pilot Ignition System

  • Energy saving ignition that ignites pilot only when there is a call for heat.

Altitude Certifications

  • Universal low NOx is certified up to 2,000 feet.
  • High altitude certification for models GN76-200 and GN91-200 is 5,000 feet; and model GN100-200(A) is 8,000 feet.

Patented Anode Rods

  • Anode design utilizes multiple magnesium rods to ensure corrosion resistance for a long tank life.


  • 3-Year limited tank warranty


  • 35 to 100-Gallon Capacities
  • 125,000-399,900 BTU/h
  • Natural Gas Top-Front-Rear Inlet/Outlet Water Connections

Energy Guide Details


  • HLW on selected models
  • US CSA (Star)
  • AHRI B&W


Universal Low NOx


  • 3-Year limited tank

KwikComfort® Financing can help make your purchase even easier.
Ruud makes it easy to find a financing option that works for you! With many options and benefits available, KwikComfort Financing is the best way to get the home comfort you need without the wait.

  • Applications made easyWe'll help you avoid lengthy contracts, headaches and hassles.
  • Kwik credit decisionsYou'll get an answer to your application within minutes.
  • Fast credit for the futureFinance your Ruud equipment and anything you want to add later.
  • Reduced interest/fixed paymentsGet low interest and fixed monthly payments until the purchase is paid.
  • Minimum monthly paymentTake advantage of convenient monthly payments that fit your budget.
  • Deferred interest/no interestEnjoy interest-free payments as long as the balance is paid by the due date.