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MAXIM 3 Water Heaters

Available with AquaPLEX Duplex Alloy

Less than 20 ppm NOx available on most models!

MAXIM 3 heater is a three pass, vertical tube water heater with medium capacity storage and medium-to-high recovery capacity. MODBUS connectable operating control. Smaller footprint compared to boiler/sidearm tank systems.


  • 84% thermal efficiency per ANSI Z21.10.3 testing.
  • Heaters qualify for LEED certification.

Inputs / Storage

  • 125 gallon series: 399 - 500 - 750 MBtu
  • 250 gallon series: 500 - 750 - 900 - 1000 - 1500
    1800 - 2000 MBtu
  • 300 gallon series: 500 - 750 - 900 - 1000 - 1500
    1800 - 2000 MBtu

Burner / Venting

  • Natural gas or LP gas. (low NOx available in natural gas only)
  • Premix surface burners (less than 20 ppm NOx on most models)
  • Gas trains are UL compliant and include a second safety shutoff valve and gas pressure regulator.
  • Product vents negatively through type B double-wall material.
  • Factory equipped for connection to direct combustion air.

Corrosion Protection

  • AquaPLEX® duplex tank material requires no lining.
  • All tank connections are non-ferrous and removeable. Lining protection is not compromised when pipe is threaded into fittings.


  • ETL listed to US and Canadian safety standards.
  • FM compliant.
  • ASME, section IV, part HLW stamped
    and National Board Registered.
  • CSD-1 (GE-GAP) controls optional.


  • AquaPLEX tank with a 15-year warranty

Tank warranty covers leaks, production of discolored /rusty water, chloride stress corrosion cracking or defects in material or workmanship

  • One-year parts warranty
  • First-year service policy (freight and labor coverage)
  • Long-life service policy (optional)

Information provided above is summary only. Refer to written warranties and service policies for full details.