pentair 400

  1. S

    Ridiculous reading on automation temp reader

    I have a pentair mastertemp 400, and I tried to turn on my spa yesterday and got a ridiculous reading of 255 plus degrees; obviously the heater never turned on. Any ideas? I did try to search the forum for others who have come across this.
  2. F

    E05 error on Pentair master temp 400HD

    Hello, yesterday I started getting an E05 error on my Pentair master temp 400 HD. I opened the heater up and put a multimeter across the flue temperature sensor and I got 3.8 ohms. So I’m assuming that the temperature sensor is OK. The air intake is also fine and from what I can tell the water...
  3. A

    Pentair Mastertemp LCD Replacement

    Hi, Everything in my Pentair Mastertemp Heater is working properly except the LCD screen that displays the temp. I can see that the backlight is coming on but there is no display of numbers. All buttons on pad work as normal and from reading other threads I realize the LCD screen is on the...
  4. J

    Issue with my Pentair Mastertemp 400

    Hi all. I am having an issue with my pool heater and I saw similar issues in some old threads so thought I would post here. I had a pool guy change out my thermastor and then my control board in my Pentair Mastertemp 400 (about 6 years old) trying to resolve the my issue. Basically I could not...
  5. K

    My Pentair Screenlogic App Won't Control The Spa Temperature Anymore

    Hello, I found this forum from googling about my problem, and not quite finding the answer I was looking for. I'll try to do this properly, so as not to frustrate those who want to help! I have a Pentair pool/spa that was installed somewhere around 2015/2016. We bought the house in 2018, and I...
  6. A

    SWG Heater requirements

    Hi all, Looking to switch to SWG and will be replacing my 35 year old heater. (Just bought the house). Anyhow, looking at the Pentair master temp 400 and was wondering if the Salt is a reason to upgrade to the HD version (cupro nickel). It would cost $800 more net. (SoCal gas has a $400 rebate...
  7. M

    Pool/Spa Heater (cycling on and off every 45 seconds). Takes 1.5 hours to heat spa

    I am new to this site and I pay a professional pool service to take care of my pool. Our Setup PentAir Master Temp 400 - the pool was installed in Sept 2020. PentAir Water Pool and Spa Automation. Salt Water Pool. Back in Dec 2020, we set our spa (which we weren't using very often) to 101 and...
  8. J

    Pentair Heater Manifold Leak

    Hello. After the freeze in Texas I noticed water pooling under the manifold of my pentair heater while the pump is running. I found the leak (slowly drips water) on the return pipe. My guess is the freeze created a small fracture in the pipe. Any ideas how to repair this or will I need to...
  9. M

    MasterTemp 400 HD Shutting Off Rapidly

    I have a mastertemp 400 HD heater and I'm having an issue with maintaining the temp. Initially when you turn it on, it stays on and heats it up well. However once it reaches the set temp, it will shut off Rapidly instead of staying on for a few minutes to heat it back up to a degree or two over...
  10. N

    Mice in Pentair

    Hi. So my heater wasn’t working for a bit. So a YouTube video showed me how to bypass the membrane. Sure enough a $30 part saved the day. Or so I thought. After firing up for a bit - I noticed the sound of slightly restricted airflow (just sounded off and some whistling). However...
  11. N

    Pentair MiniMax Plus 400 Heater cuts On/Off

    Hello, I have a Pentair Minimax Plus 400 heater. When I turn it on to heat the pool or spa it'll turn on for about 5-10 min then shut off for 15 min or so then turn back on for another 5-10 min then shut off again and it does this over and over. When it shuts off all lights will be on except the...
  12. B

    Pentair master temp 400 afs light

    I have a Pentair Mastertemp 400 with an AFS light on. The heater turns on and runs for 10 seconds and turns off and throws the light on. Before this light came on I replaced the pressure switch, high limit switch, thermistor, manifold bypass valve, and control board due to an issue caused by the...
  13. Kihon

    Another.....Mastertemp 400 with AGS LED + Service Heater LED

    Hello TFP experts. I have Mastertemp 400 that's about 5 years old. I have attempted a a deep dive search here and found a few threads that very similar. MasterTemp 400 Heater won't stay running, but it was never confirmed if a new control board solved the problem? Mastertemp 400 - Burner...