Pentair Mastertemp 250 24 VAC short keeps blowing fuse

[ajw22]

@ajw22 yes the fuse blew with just j7 connected

In post #3 you said...

The fuse doesn’t blow with J7 on.

Confirm which is correct as your posts are conflicting and confusing.

 

[Darkmanh]

@ajw22 the fuse doesn’t blow with just J7 connected to my original board but there's nothing on the display and the heater doesn’t start. When I plug in the new board just to J7 the fuse blows.

 

[ajw22]

@ajw22 the fuse doesn’t blow with just J7 connected to my original board but there's nothing on the display and the heater doesn’t start.

Which board do you want to work with?

It will not display or start with just J7 connected. Now what happens if you add one connector at a time?

When I plug in the new board just to J7 the fuse blows.

That indicates the board is bad.

I am suspicious of parts like that bought from unknown dealers on Amazon.

If you want to replace the board you should get the latest one. The new Control Board Kit 461105 comes with "6 button" membrane keypad. When replacing a control board on an older heater that has a 5 button keypad, you will also need to update the heater to have the 6 button keypad.

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com

 

[Darkmanh]

Which board do you want to work with?

It will not display or start with just J7 connected. Now what happens if you add one connector at a time?



That indicates the board is bad.

I am suspicious of parts like that bought from unknown dealers on Amazon.

If you want to replace the board you should get the latest one. The new Control Board Kit 461105 comes with "6 button" membrane keypad. When replacing a control board on an older heater that has a 5 button keypad, you will also need to update the heater to have the 6 button keypad.

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com

At this point I don’t know if the old board is bad. The last test I did with the original board I was able to connect all the connectors and membrane pad and the fuse didn’t blow. However, the heater was not displaying anything and none of the LEDs worked. I tried removing the membrane pad and jump the connectors to turn on the heater and nothing happens so I believe that indicates the board is bad according to the troubleshooting guide. But now these boards I ordered are blowing the fuse so I guess the only option is to return them and try to order the new control board kit you suggest. I don’t have any automation on my pool. Would that kit work with my heater?

 

[ajw22]

At this point I don’t know if the old board is bad. The last test I did with the original board I was able to connect all the connectors and membrane pad and the fuse didn’t blow. However, the heater was not displaying anything and none of the LEDs worked.

That is usually a symptom of one of the 24V safety sensors being open.

I tried removing the membrane pad and jump the connectors to turn on the heater and nothing happens so I believe that indicates the board is bad according to the troubleshooting guide.

I don't know what guide you are following.

But now these boards I ordered are blowing the fuse so I guess the only option is to return them and try to order the new control board kit you suggest. I don’t have any automation on my pool. Would that kit work with my heater?

Yes it should. Did you read Pentair MasterTemp Heaters - Further Reading

 

[Darkmanh]

 

[Darkmanh]

@ajw22 the troubleshooting guide from the manual is what I followed. So you mentioned a 24v safety sensor which I had no idea about. How does that work?
I ordered more fuses because I depleted the 10 I had so I’m planning on testing the original board again. I will return the board I ordered which blows fuses and if the original board doesn’t blow the fuse I guess I would need to reset the 24v safety sensor? How do I do that?

Thank you very much!

 

[Darkmanh]

@ajw22 this morning I reinstalled the original board and new fuse. I followed the step by step process of plugging in each J connector and checking the fuse. I was able to plug in all the connectors and the fuse is still good. I check voltages to the FS and they’re 24VAC but the display on the board is blank and none of the leds turn on. I connected the membrane and nothing happens when I push the buttons. If I disconnect the membrane ribbon cable at J6 and jump the 5th and 6th pins as suggested in the troubleshooting guide, noting happens. So I guess after all I still have a bad board. Do you have any suggestions to make sure the board needs to be replaced?
Thank you!

 

[ajw22]

@ajw22 this morning I reinstalled the original board and new fuse. I followed the step by step process of plugging in each J connector and checking the fuse. I was able to plug in all the connectors and the fuse is still good. I check voltages to the FS and they’re 24VAC but the display on the board is blank and none of the leds turn on. I connected the membrane and nothing happens when I push the buttons. If I disconnect the membrane ribbon cable at J6 and jump the 5th and 6th pins as suggested in the troubleshooting guide, noting happens. So I guess after all I still have a bad board. Do you have any suggestions to make sure the board needs to be replaced?
Thank you!

Dunno. If you are confident you have everything hooked up correctly then get a new Pentair board from a reliable dealer.

 

[Darkmanh]

@ajw22 I’ve checked again that all connections are correct and that the voltages are correct. Also, I’ve received the updated board and 6 button membrane with FC connector. I will be installing them today and post the results.

Thank you!

 

[ajw22]

@ajw22 I’ve checked again that all connections are correct and that the voltages are correct. Also, I’ve received the updated board and 6 button membrane with FC connector. I will be installing them today and post the results.

Thank you!

Looking forward to hearing what happens with the new board.

 

[Darkmanh]

@ajw22 I installed the new board and 6 button pad and it worked like a charm
Thank you so much for your help.