Pentair MasterTemp 300 - no power, no display

[JPCunningham129]

Hi,
I have a Pentair MasterTemp 300 that suddenly stopped working. It worked fine about a month ago, but now it has no indication of life. I checked the fuse, and it appears to be fine and i tested with a multimeter continuity test. Unsure of where to go from here.

 

[ajw22]

Is the Mastertemp connected to automation?

 

[JPCunningham129]

Sorry, just filled out my sig...Yes it is connected to Aqualink RS. I press the 'heater' button as normal. I hear the click on the controller click, but nothing on the heater. No display or anything.

 

[ajw22]

You say you checked the fuse so you should have seen where the 2 wire fireman’s switch is connected. Disconnect the two wires and jumper the connection in the heater. That puts the heater on local control.

If the heater control panel turns on then your problem is in the Aqualink.

If the heater does not turn on then we will discuss how you dig into it.

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com

 

[JPCunningham129]

Sorry for the delay. I used the Fireman Switch, and it is still dead. Please see pictures to verify I jumped it properly.

Before:





After:

 

[ajw22]

That confirms the problem is in the heater.

If you are comfortable working with high voltages I would use the multimeter and starting with the CB powering the heater check for voltage coming into the heater 12 pin receptacle. Confirm the correct voltage receptacle is installed and secure.

You can see on the diagram below the high voltage goes directly to the transformer that lowers it to 24V AC, Check for the 24V AC at the transformer and at the 24V AC plug into the main board.

If you have 24V AC to the PCB then the heater display should light up.



@swamprat69

 

[JPCunningham129]

ok, so if i am understanding correctly. check the power (top right in the diagram that says 24vac, should be the transformer) and also check 24vac in the middle top of the 'operating control' on the diagram.. is that correct?

 

[ajw22]

ok, so if i am understanding correctly. check the power (top right in the diagram that says 24vac, should be the transformer) and also check 24vac in the middle top of the 'operating control' on the diagram.. is that correct?

Yup.

 

[JPCunningham129]

I think we have a culprit. I tried to test power to the control board and got nothing. i went to the transformer, i tested the 3 wired connection (i believe it to be coming off the power whip) and got power. I connected that back to the transformer, and tested the 2 wire connector coming off the top of the transformer, and it seems to be dead. Not a smart man, but would that mean the transformer is not good?

 

[ajw22]

Yellow/Blue wire connector should have 24V AC. Looks like you found it. That transformer looks grungy.

Pentair MasterTemp transformer P/N is 42007-0107. P/N 42007-0107s is for units made after 2003.

 

[JPCunningham129]

Thank you. I will respond once I replace the part. Appreciate your assistance.

 

[JPCunningham129]

Thanks Allen!

Appreciate your help. I replaced the transformer and it looks like it now has power and is firing up properly. I just need to go back and take the jumper off.

Thanks again!