Pentair Minimax NT 400


In The Industry
Aug 17, 2020
Winter Haven Florida
Working on a Minimax NT 400, consistently getting an E05 error, The machine goes through it's normal cycle when you select spa or pool on the heating function, the temperature range is set to the maximum 103 on either mode , lights and heats as it should then turns off in just a few seconds, sometimes it goes through 3 cycles then sets off the error shuts down and other times it keeps lighting and turning on and off as if it reaches temperature. I have replaced the igniter, and the complete ignition module on this unit, also the flame sensor, I replaced the Thermistor even though the one in place seemed to read accurately. I have checked the wiring and connectors to make sure they are clean and have been making contact. can anyone help with this issue, I know this is an old unit, however it is very clean or I wouldn't be even working on it.

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Hello and welcome to TFP! :wave: Sorry no one has replied to your heater issue. Not sure if this is still an issue for you by now. Me personally, I'm no help here in hot Texas. :) We have many heater users, so hopefully someone will reply. In addition, I'll tag @Pool Clown for assistance. Thanks for using TFP and posting on the forum.
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