Pentair MasterTemp 400 Control Board Replacement

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oddeven21

Silver Supporter
Apr 8, 2024
12
Southern California
Hello, my heater unit is from 2016 and I've confirmed the board is most likely defective. I started researching replacements and I'm a bit confused by model numbers so I was hoping someone has dealt with this before.

I have the r13 version model 42002-0007. According to this pentair doc my board was superseded by model 461105. I've found several "42002-0007S" boards on ebay (like this one) but they look very different from my board. The 461105 boards I find online all appear to be OEM boards and are very pricey!

Will either of those board replacements work? Thanks for your time.

Here is a photo of my board
IMG_20240408_162255665_HDR.jpg
 
Welcome to TFP.

Yes, replacement genuine Pentair MasterTemp PCBs are pricey but they work.

The board you linked to on eBay is a clone third party board. Many members have had problems making non-Pentair boards work while they have worked for some. You pay your money and take your chances.

We know how genuine Pentair boards work. We cannot help with third party boards other then to suggest returning it and buying a genuine Pentair board. In every case a genuine Pentair board has worked when a clone board has not.

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com www.troublefreepool.com

All that said, would you like to tell us why you think your board needs replacement?
 
Thank you for that link, very informative article. My heater suddenly stopped working the other day, the keypad display does not light up, no error codes on the board, and nothing happens at all. I had issues with the keypad prior to this so I just immediately replaced that hoping it was the problem but still no luck.

I initially was just gonna throw $80 at a new board and hope that fixed the problem but I should probably buy the oem board and do it right. However I should also probably confirm the board is the actual problem before shelling out 100s :)

Any advice on that front? I poked around with my non-contact voltage sensor so I know power is coming into the transformer but I'm not very savvy with the multimeter beyond that. I looked over some previous posts and tried reading the wiring diagram but I was just guessing at best.
 
You cannot do much real diagnostics with a non contact voltmeter. You need to be able to check voltages or continuity with a multimeter.

Is your heater connected to automation?

Have you checked the fuse by the fireman’s switch connection?

Pentair_MasterTemp_Firemans_Switch.jpg
 
Disconnect the two yellow wire nuts at the firemans switch and the two wires that run to your EasyTouch panel.

Twist together the two wires on the heater and put a wirenut on it.

Your heater is now disconnected from the EasyTouch. Your heater is now in local control from its control panel.

Turn on your pool and press POOL ON or SPA on on the heater and see if the display lights up.
 
Our Sta-Rite 400 maxitherm propane heater has rusted a good sized hole into the top of the lower heat box by the exchanger, so we will have to replace it. (that will be a new thread coming soon.) Our first one lasted 12 years, until 2010, and then actually started on fire. That was scary. We replaced the two boards in late 2018. It sounds like it would be good for me to get the boards out and try to sell them on eBay. Or offer them here for shipping cost.
 
oddeven21 said:
Ok finally had some time to get back out there. I bypassed the automation as you described and still no power to the unit
Click to expand...

Show me a pic of what you did.

You press POOL ON or SPA ON with your pump running?

You need a multimeter to test voltages and continuity for doing further diagnostics.
 
Thanks for the help thus far and again apologies for the delayed replies. Here's a pic of the jumped fireman switch.

And yeah with the pump running I press SPA ON and POOL ON, still no lights or anything on the control board. I do have a multimeter but I'm not sure where precisely on the board I need to check for the 24v that it's supposed to be getting.

IMG_20240415_170624317.jpg
 

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See the transformer on the right side?

Follow the 24V AC output to the 4 pin connector on the board. Check for 24V AC on the two left pins of the connector.

You will see the right two pins loop to the firemans switch wires you twisted together. Check for continuity between the those two pins.

If you have 24V AC and the firemans switch has continuity at that connector then the board is powered.

Check the membrane connector J6 that the keypad is connected.

Pentair MasterTemp 24V Wiring.png
 
oddeven21 said:
Ok confirmed continuity on the fireman switch and confirmed 24v going to the board. Sounding like the board is bad then?
Click to expand...
Sounds like it. I recommend you get a genuine Pentair replacement PCB.
 
ajw22 said:
Sounds like it. I recommend you get a genuine Pentair replacement PCB.
Click to expand...
Will the working board in my Sta-Rite Max-e-therm 399,999 BTU work in this heater? It's genuine Pentair board and was installed in 2018 due to a bad board. We are replacing the heater and could extract the boards so they don't get trashed. I'd provide it for a few bucks shipping to help a fellow TFP supporter. @oddeven21
 
CFlaPool said:
Will the working board in my Sta-Rite Max-e-therm 399,999 BTU work in this heater? It's genuine Pentair board and was installed in 2018 due to a bad board. We are replacing the heater and could extract the boards so they don't get trashed. I'd provide it for a few bucks shipping to help a fellow TFP supporter. @oddeven21
Click to expand...
It should. It is worth a try.
 
So quick update, I received the board that @CFlaPool graciously sent me but unfortunately we're still stuck with the same problem. The heater display isn't lighting up and no error codes on the Fenwal. I had a pool tech friend of mine come by and he also diagnosed the issue but was basically stumped. We again confirmed the board is getting 24v and we followed the power back through the transformer and all the lines coming into the box, everything checked out. He suggested maybe the Fenwal could be bad?

Thanks for all the help thus far!
 

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