By Sta-Rite



Part # SR333LP

Alternate Part #'s 33677, PENSR333LP, STA-15-503

Product Description

Sta-Rite Max-E-Therm Pool and Spa Heaters are certified for outdoor or indoor installation. Features include an LCD temperature readout with dual thermostat controls, temperature safety lockout, and 6 position control panel. PMG burner technology requires no outdoor draft hood. Proven Dura-Glas Resin provides rust-proof construction.


  • Rust-Proof Enclosure - Unlike conventional metal enclosures, the Max-E-Therm is made of Dura-Glas® - a sleek, lightweight and rustproof material that withstands heat and the elements.
  • Exact Temperature Controls - Weatherproof temperature controls that can be set to your specifications.   Pivoting UV-resistant plastic visor covers the Digital Display.   Accommodates temperatures for both a pool and a spa running off of the same heater, in Fahrenheit (°F) or Celsius (°C).
  • Energy Efficient - PMG combustion technology improves Efficiency and reduces operating costs.  Also provides faster heat ups.  The three sizes available are 83% efficient or higher.
  • Safety - Internal safety feature sets maximum temperature levels.  Full diagnostic lights for troubleshooting problems.  The diagnostic indicator lights tell you whether to service the heater or the pump/filter system.
  • Environment Friendly - Exceeds all air pollution standards.  Electronic ignition enables you to never worry about a pilot light blowing out or leaking gas.
  • Proven Sta-Rite Technology - The Max-E-Therm Heater is the newest member in our family of advanced technology pool and spa products.  Our quality pumps and filters have been used for years to enhance the enjoyment of pools and spas nation wide.
  • Warranty - 2 years parts & labor

Product Specifications

333,000 BTU
Heat Exchanger:
Special Feature:
Low NOx Emission

?     Asked on 5/14/2015by Inyo Visitor

Have a 20,000 gallon pool. Will the this heater be enough or should I get the 400,000 BTU. Don't really care if the 333,000 takes a little longer to heat up the pool

A  Answered on 5/15/2015 by InyoPools Product Specialist Patrick P.

The 333,000 would be more than sufficient for a 20,000 gallon pool.

?     Asked on 1/20/2016by Joseoh

How many volts?

A  Answered on 1/21/2016 by InyoPools Product Specialist Lennox H.

Hi Joseoh, The Max-E-Therm Heater's w/ Electronic Ignition can be connected to 120 or 240 Volt, 60 Hz., Single Phase power.

?     Asked on 5/31/2016by Bob

Is this LP version of the Max-E-Therm Model 333 adequate for a 24,000 gal pool?

A  Answered on 6/1/2016 by InyoPools Product Specialist Lennox H.

Hi Bob, This unit does use propane gas and is adequate for a 24,000 with a surface area of 500-700 sq.ft.

?     Asked on 4/19/2018by viruchy

My heater motherboard is defective and it won't turn on the heater. Can we just replace the motherboard? Do you carry motherboards for this heater?

A  Answered on 4/19/2018 by InyoPools Product Specialist Lennox H.

Hi, Viruchy.  Yes, the Control Board Kit Basic - 42002-0007S is available. 

?     Asked on 9/7/2018by andy

GM, Can the 333k btu unit be changed over to a NG unit at a later date replacing an inexpensive part or must we buy another unit? We currently use propane but just got our house switched to NG and were thinking of running the pipe to the heater within a year or two.

A  Answered on 9/7/2018 by InyoPools Product Specialist Lennox H.

Hi, Andy. This unit can be converted to Natural Gas using the Propane to NG Conversion Kit - 77707-1421