pentair 400

Hello Everyone, Hopefully, someone knows a bit about Pentair Mastertemp 400 units. I bought a house a couple of years ago so not sure how long the heater has been here. When I start it up, it will heat for a couple of minutes, then shut down saying "Service Heater." I decided to do some...

Looking for guidance and advice for an issue I’m having with my Pentair Mastertemp 400 gas heater. We keep the heater at 68 through winter and raise the temp when we want to use it as a “hot pool”. Turned the temp to 80 two days ago to get it closer to our desired temp for Christmas Eve. On...

Hi everyone. I cant seem to find a 2024 fix for this issue. Here is a bit of what happened to me when i bought my home. First pool and just dont know much but i learn pretty quick from what ive read here. Im just stumped now. Dont know where the issue is now. Bought the house heater didn't...

Hello, Thanks in advance for the help and comments. I have a Pentair 400 Mastertemp and I am currently getting a AFS error. I have checked the other threads on here regarding this issue and haven't pinpointed the issue that I am having. - I have checked the airflow sensor and that seems to be...

Hello, I have a Pentair Mastertemp 400 (almost 6 years old). I have been getting as service heater light (solid red light on the Fenwal Ignition Controller module - Control Fault). The heater will run normally about 50% of the time that we use it. On the occasions that the service heater light...

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.

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...