I didn’t think nothing of it, and went along my cleaning. How do I reset the igniter? After a while, the heater is not getting hot. It’s main job is to keep the heat source from hurting the heater. Try checking indoor controller. After install of new control panel heater kicked on and worked perfectly. Some of the digits on the digital display do not work so i can not read an error code if there is one. My heater starts then shuts off within 20 seconds. Do you hear any noise coming from your pool heater like a “click” or a “thunk” or is it just dead? It will run for a minute. The Pentair MasterTemp pool heater adopted the sealed combustion chamber with controlled exhaust design. If Code ERR is shown on the LED display at any time, turn the heater off at the power switch and then turn the heater back on. View online or download Pentair MASTERTEMP 300 HD Installation And User Manual Yes . I fixed it today, a mouse had chewed through the air tubing coming off the fan causing the problem! When the DDTC detects an error, the display will show Exx,  where Exx is the error code of the DDTC fault. And the problem still persist. Any ideas of what could be wrong? I see a thread on there similar to this question, you may have already posted. Specific details are described on the warranty registration card which is included with the product. Don't miss out on exclusive deals and discounts! I can’t find this problem in any of the manuals or code guides. Replace if necessary. There are three ignition modules available for the Pentair Minimax NT: 472150, 472447, 472449. great article. It fires up and starts heating and about a minute later shuts down and go's to service heater light. it was showing a Err Eo4 message. Trys to ignite, with a slight whining noise. It means the temp is too “LO” for the heater to operate. Specific details are described on the warranty registration card which is included with the product. The last part of the E05 section of the article states this: Control board- You may want to check the lights on the back of the control board. I tried a new thermistor and that didn’t cure the problem. I cannot see any air flow switch on my system it is NT 300 STD N. IS there some kind of diagram that would show me where to look? Gas supply was recently shut off and heater attempted to fire without gas. Why pay someone to do something you could have easily done yourself? the heater simply does not fire and not error messages. The heating light is an indication that your unit successfully fired the main burners and will stay on until the water reaches its desired temperature. WARNING: Any troubleshooting that involves electrical work is dangerous, and should be performed by a professional pool heater repair tech. Shut it off went back several hours later and it is now doing the same exact thing… Flashing “OFF” and not kicking on. if that doesn’t help, then you may need to have a technician come out to inspect the unit. But for a last ditch effort try TroubleFree Pool’s forum, they usually have a fix. Code, Part 1 (Canada). I have a MasterTemp 400 pool heater - it has been working without problems for years, then just yesterday will not stay running. Hopefully, they can help you keep your heater running. No service light every came on….??? Any reason why this happens? Try this manual page 33, Pentair MiniMax NT Troubleshooting Manual. I have a MiniMax Nt 400dv. I have a Pentair NT. My first guess would be an airflow issue :). Typically, this is caused by a bad igniter, but not always. If something should go wrong, the lights will aid in troubleshooting the problem. Pool and spa heater pentair max-e-therm series (56 pages) Swimming Pool Heater Pentair MiniMax NT LN Operation & Installation Manual. I took a chance and purchased this board. This is an excerpt from the Pentair Minimax Manual service light section. Still, with all the information available, sometimes it can convolute the information and cause even more confusion. It still does the same thing. The only lights on the display that are lit are Power, Pressure and temp, the heating light doesn’t light up. I assujme this should not be happening. With that in mind, we  gathered as much information and  attempted to include all the different reasons why an error code may present itself. When I turn on the heater the blower turns on, there’s a click after a minute but then the air blowing never gets warm. Upon detection of excessive heat within the inner front panel, the fuse will open the safety circuit causing the shutdown of the heater. A good rule is, when in doubt- give Pentair’s technical support a call. It seems many of the problems I see can be traced back to electrical connections to the various sensors or circuit boards. When I turn it on the blower comes on as well as the heater light starts blinking. Good morning, AquaComfort Pool Heat Pump Service & Support, AquaComfort Vintage Classic Series (2003-2010), Pool Heater Sizing | Pool Heat Pump Sizing | Savings Calculator, Pool Heat Pump Repair | Pool Heater Repair, Energy Saving Tips For Your Swimming Pool, Measure water temperature with a thermometer to rule out a faulty temperature sensor, Hire professional pool heat pump repair tech to inspect control board, thermistor, and unit, See HIGH WATER TEMP troubleshooting steps, Check that pool pump is sending water to heater, Ensure that pool pump is receiving enough water, Check that your pool system’s multiport valves are on the correct settings, Have pool heater repair tech check for bad pressure switch (or check it yourself), Seek pool heater repair tech to troubleshoot the water thermistor, Seek pool heater repair tech to troubleshoot the defrost thermistor, Check that transformer supply voltage is within 208 – 260 volts, Check that transformer output is between 24 – 28 volts, Replace transformer is voltage is below those ranges, Check that heat pump supply voltage is between 208 -260 volts, Ensure that pool pump is sending water to your pool heater, Check for any blockage in baskets and filters that are affecting water flow, Have pool heater tech inspect higher-pressure switch, The unit may have a refrigerant leak. The tech I spoke to sad, you main have a display issue, along with a deeper issue preventing your heater from turning on. Minimax NT Pressure Switch – Plastic Body – 470190Z. Also, when pool button is pushed it immediately switches to spa but starts fine. I have a pentair minimax 400. It seems like a catch-22 to me, though. WARNING RISK OF ELECTRICAL SHOCK OR ELECTROCUTION. But the water coming out of the jets in the Jacuzzi never gets hot??