by Mark Garcia January 08, 2019
Pentair pool heaters come from the legacy of the Purex-Triton Minimax heater, when Pentair purchased the Purex company. In 2004, Pentair acquired the Sta-Rite company and it's Max-E-Therm heater technology. The Pentair MasterTemp pool heater adopted the sealed combustion chamber with controlled exhaust design.
The MiniMax pool heater design is no longer being made by Pentair, but parts will continue to be manufactured for years to come, so fear not if you have a Pentair Minimax, which shares a common gas pool heater design with other brands like Hayward and Raypak.
Today's post is specifically about the not-so-new style of pool heater design, used in the Pentair MasterTemp and Sta-Rite Max-E-Therm heaters.
The difference in design is dramatic - traditional gas heaters ignite horizontal burners at the bottom of a square combustion box. The air space above the burners heats up, which heats the copper finned tubes laying on the top of the combustion box. The water circulating through the copper heat exchanger tubes absorbs the heat, and exits the heater a few degrees warmer than when it entered.
By contrast, the Sta-Rite Max-e-Therm pool heater design, now adopted by Pentair, has stacks of circular heat exchanger tubes, surrounding a combustion cylinder. Gas and air are mixed and ignite in the cylinder, which warms the tubes that are wrapped around the central burner chamber. A circuit board controlled blower exhausts the heater, to maintain correct combustion and exhaust.
Troubleshooting the stacked exchanger type of heater is not much different than other electronic or digital pool heaters. The controls and circuit boards for the Max-E-Therm and the MasterTemp are fairly identical. Even the new MasterTemp aboveground pool heater has the same design, and the same troubleshooting procedure. The error codes below can get you started with understanding what your heater is trying to tell you.
Our Pentair Matertemp Troubleshooting Guide starts with the error codes shared by both models, and follows into a 6 page flowchart to step by step troubleshoot a Pentair or Sta-Rite pool heater, and get it firing again fast!
|PENTAIR MASTERTEMP ERROR CODES|
|AGS||AUTOMATIC GAS SHUTOFF|
|HLS||HIGH LIMIT SWITCH|
|AFS||AIR FLOW SWITCH|
|SFS||STACK FLUE SENSOR|
|E02||HIGH LIMIT SENSOR|
|E03||THERMAL FUSE ERROR|
|E05||STACK FLUE SENSOR|
The burners on this type of MasterTemp/Max-e-Therm heater are quite unique from previous generation pool heaters. Older style heaters use a low horizontal manifold supplying dozens of individual burners across the bottom of the burner tray, shown at left.
The Burner System of the MasterTemp/Max-e-Therm heaters is one single burner, called the Flame Holder, shown right. The burner is located in the center of the combustion chamber, wrapped by the circular copper heat exchanger tubes. The single glowing burner is aided by the blower fan, which regulates the correct amount of exhaust and is plays a large role in correct combustion.
The biggest fear about the heat exchanger is that corrosion can occur to the relatively soft copper finned tubes, causing them to develop pinhole leaks. Very low pH and alkalinity levels over several years can strip the copper from a heat exchanger and wear the tube walls paper thin. Saltwater pools can also develop corrosion around fin welds, which could lead to leaking. Cupro Nickel heat exchangers can be used for much greater resistance to the effects of salt water corrosion.
Leaking heat exchangers are often confused with sweating or condensating heat exchangers. A second major problem with heat exchangers is scaling water conditions and poor combustion could lead to build-up of lime scale inside the copper tubes, which renders the heat exchanger useless and requires a replacement.
Just another way that Sta-Rite built a radically different heater. A completely redesigned pool heater that allows the Pentair MasterTemp and Sta-Rite Max-e-Therm heaters to be over 50% smaller in size and footprint.
I sincerely hope that this post has helped you solve your pool heater problem!
Thanks for Reading!