Pentair mastertemp 400 heater transformer repair

Heater would not turn on. Video shows and explains how to complete transformer replacement.

[@jordanonofer3886]

Thanks for sharing. I'm having issues this year also. First was stack flu sensor a few weeks ago. Did that myself. It worked. Yesterday I lost power at some point during it running. Fuse was good. Still put new one in anyhow for the cost. Was gonna stop there and call repair guy. But your vid definitely showed me I can handle the transformer on my own also. Thanks for making the video. I hope it works lol. Very very good job on the video also. Thanks again

[@giantessmaria]

thanks my friend.... the joy of this heater is its so easy to work on.... i replaced my board and membrane pad twice already, no prob... its not cheap, but much better than paying a repairman.

[@MrBrianJoseph]

I’m in the pool business for years now and just wanted to say good job your video was thorough and correct

[@chrisll707]

Big Thank You!!! Exactly what I needed to see

[@FLYBOY123456789]

OUTDAMNSTANDING Gilbert...same problem with mine...thank you sir for an excellent video. Clean tight house...love it.

[@gilbertrivera8369]

Thanks for the feedback. Happy I was able to help out and help save time, money, frustration, etc.

[@jesusvalenzuela5601]

Thanks, I needed that info. Be safe.

[@AquaTech225]

Mastetemp 250 an 400 an the Sta-Rite Max-E-Therm all operate the same way. I’m a service tech for pentair. All of the parts for these heaters are interchangeable and operate the same way, an the same order of operations. The only difference’s in the sizes will be gas orifice size, and if it’s natural gas or propane. Also the blower intake Orifice. So that’s 3 items but if your heater has ran before. That’s not parts you’ll ever be changing. But thermal regulator Thermistor High limit AGS sensor Water pressure switch Gas valve Motherboard/pcb Ignition module Wiring harness Fuse All of them items are going to be interchangeable.

[@rbobey1]

Very helpful Thanks

[@michaelchonos4280]

Looks like you did a great job on that Pentair master temp 400 come fix mine I’ll pay you

[@zsharp1772]

Thanks for the video. Question for ya… when you hold down the heater off button until it displays program settings AD1 or AD0 and SF1 or SF0 … what do those settings do?

[@rickdavis2205]

Gilbert, can you tell me how you determined it was the transformer and not the circuit board? My Pentair master 400 has no display. I have power to the unit.

[@gilbertrivera8369]

I wish I would have included in the video how I narrowed down my problem to the transformer. Basically you use a voltmeter to measure if current is going to the transformer and whether any current is leaving the transformer. If current is going to the transformer, but nothing measured leaving the transformer, this is usually a sure sign that the issue lies with the transformer. Hopefully this helps.

[@paulabrilla5531]

Hi, I have the same problem except that I see the PS LED at the back of the panel. The heater would at least try to start. It will try to fire up to call for heat and it will be OK for few seconds and then the PS LED would light up. I replaced the Pressure Switch about a month ago and it worked for the 3 times I used the heater and now, it won't even try to startup. No sound whatsoever. The Service System lights up right away together with the PS LED.

[@gilbertrivera8369]

Good luck. Calling Pentair tech-support was also helpful in regard to trying to troubleshoot your problem and rule out different solutions. This way you’re not chasing parts.

[@StanleyASmith-im8bi]

Thanks!! Gilbert i think i have the same problem.

[@gilbertrivera8369]

I wish I would have included in the video how I narrowed down my problem to the transformer. Basically you use a voltmeter to measure if current is going to the transformer and whether any current is leaving the transformer. If current is going to the transformer, but nothing measured leaving the transformer, this is usually a sure sign that the issue lies with the transformer. Hopefully this helps.

[@StanleyASmith-im8bi]

@@gilbertrivera8369 Cool, I will check it out Thanks!

[@audio1484]

Hi Gilbet great video how did you know that the transformer or that specific part was bad? Can you test the transformer?

[@gilbertrivera8369]

I was not able to test the transformer itself. However I concluded that the transformer was bad because I was able to read current leading to the transformer, yet no current leaving the transformer. I wish I would have included this in the video. See my comments in my reply to Stanley Smith. I go into a little bit more detail on how to test it. Hopefully this helps.

[@damondelgado4603]

Test for 14 volts at the memory board on the J7 connector. The first three yellow wires should read 14 volts. If your getting 240 volts(120 if wired that way) by the firemans switch and no power at the board, then its the transformer.

[@eodman111]

Mine just went out. It heated for awhile and stopped dead.. the front panel is non op with the pool on and spa on buttons are lit.. I'm going start trouble shooting soon.

[@damondelgado4603]

Sounds like a stuck button maybe

[@the.trollgubbe2642]

How did you figure out it was the transformer. I have the same unit

[@gilbertrivera8369]

Pentair customer technical support, actually helped walk me through troubleshooting different components of the heater. Ultimately I determined that there was current going to the transformer but there was not any current leaving the transformer.

[@freedomaugust9078]

What causes the transformer to go bad?

[@gilbertrivera8369]

It could be a few different things. For me, I think it was a power surge in our area.

[@freedomaugust9078]

I changed a transformer in a heater and it only lasted for a bout n hour before it went bad.

[@jodycushing6996]

I just had a guy come out and he didn't test anything just said it was the heat exchanger and that it would cost $800? Said nothing about a transformer or fuse. Now I wait to see if my home owners ins will cover it but I don't think he is correct.

[@gilbertrivera8369]

Always a good idea to get a second opinion………without sharing what the first guy claimed was the problem.