Pentair Mastertemp 400 No Power/Heater will not fire

[NorthernFloridaMike]

No power on LCD
Proper line voltage
Proper 120V/12 pin installed
No voltage on on secondary side of transformer
Proper line voltage between L1 & L2
120V at transformer primary pins
Tested transformer continuity with ohm meter, resistance on low side, no continuity between white and black leads on high side
Replaced transformer and still no voltage on secondary side of transformer and now no continuity between white and black leads on high side

Any suggestions or ideas on what is wrong or I am doing wrong?
Thanks

 

[JamesW]

Pictures?

 

[ajw22]

Welcome to TFP.

How old is your heater?

Is the heater firemans switch connected to automation?

At what point did you check the 24V output of the transformer? At the J7 plug?

Pentair MasterTemp Heaters - Further Reading

www.troublefreepool.com

Heater Control with Automation - Further Reading

www.troublefreepool.com

 

[JamesW]

If you have a new transformer with a good 120 volt input, it makes no sense that you are not getting the proper output.

So, it seems like you are probably doing something wrong.

Try disconnecting the 24 volts from the board before testing in case the lines are shorting causing the voltage to read zero.

 

[JamesW]

You should get 24 VAC from the two yellow lines from the transformer to the two left pins on the J7 connector.

Maybe the board is shorted.

Try disconnecting the J7 terminal and measure for 24 VAC.

The transformer get wired differently when the voltage is 120 vs. 240.

For 120, the windings are in parallel and for 240, the windings are in series.

Remove the 120 volt selector plug and check it for defects.

Can you show how you are testing the transformer input?

 

[ajw22]

You should get 24 VAC from the two yellow lines from the transformer to the two left pins on the J7 connector.

Maybe the board is shorted.

Try disconnecting the J7 terminal and measure for 24 VAC.

The transformer get wired differently when the voltage id 120 vs. 240.

For 120, the windings are in parallel and for 240, the windings are in series.

Remove the 120 volt selector plug and check it for defects.

Can you show how you are testing the transformer input?


View attachment 468100

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View attachment 468102

James, the OP probably has the older non-connected heater and you posted the electrical diagram for the latest model connected heater. There are substantial differences in the circuits and board.

That is why I asked how old the heater was so we can discuss the appropriate circuit diagram.

 

[JamesW]

James, the OP probably has the older non-connected heater and you posted the electrical diagram for the latest model connected heater. There are substantial differences in the circuits and board.

That is why I asked how old the heater was so we can discuss the appropriate circuit diagram.

It's the same wiring for the transformer either way.

https://images.inyopools.com/cloud/documents/pentair-heater-mastertemp.pdf

472592 Rev. A (04/04/06)

 

[JamesW]

 

[JamesW]

On the primary side, you have 2 sets of windings.

White is common, black is 120 and orange is 240.

For 240, you use both sets of windings in series.

 

[NorthernFloridaMike]

I have the 42001-0107 transformer pictured above on a heater that is year old.

There is no low voltage output between the yellow and blue wires and no continuity between the white and black wires on the transformer. There is 120V going into the transformer.

 

[NorthernFloridaMike]

A couple more questions answered:
- Fireman's switch is connected to automation
- Tested transformer at output, and J7 terminal with it disconnected (no voltage)
- J9 terminal on board looks burnt

 

[ajw22]

Do you have a five button or six button keypad?

 

[ajw22]

A couple more questions answered:
- Fireman's switch is connected to automation
- Tested transformer at output, and J7 terminal with it disconnected (no voltage)
- J9 terminal on board looks burnt

You have the new "connected heater" and should refer to the wiring diagram from @JamesW in post #5.

While trying to fix the heater you should disconnect the firemans switch and jumper together the connection in the heater.

I suspect your board is bad and you had some power surge run through the 24V circuit to blow out the transformer and board. You may also have a blown Fenwal box.

 

[NorthernFloridaMike]

Six button

 

[JamesW]

There is no low voltage output between the yellow and blue wires and no continuity between the white and black wires on the transformer. There is 120V going into the transformer.

Seems like a bad transformer.

Is there any continuity between any combination of wires?

J9 terminal on board looks burnt

20. Connect one end of the flame cable (Red/Black wires) to Control Board and the other end to the upper left side of the ICM. (Fig 24)

J9 is the Diagnostic connection/flame cable.

The diagnostic indicator used to be a red LED light, but it is a terminal connection on the new Fenwal to allow the Fenwal to communicate the same information.

The communication should be through the RS485.

If it is burnt, then you probably need a new board.

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/parts-sheets/heaters/pentair_heater_rs485_combo_conversion_replacement%20_kit.pdf

 

[ajw22]

What automation system do you have?

 

[JamesW]

There is 120V going into the transformer.

On which wires?

 

[JamesW]

I have the 42001-0107 transformer pictured above on a heater that is year old.

Is it still under warranty?

 

[NorthernFloridaMike]

On which wires?

On black and white lines primary lines into transformer; no output on the secondary side

 

[NorthernFloridaMike]

Is it still under warranty?

Pool installer is non-responsive so I was trying to troubleshoot/repair myself if possible