Jandy JXI 400ZN low voltage on E and F transformer 240v input

[osopolar3j]

Jandy JXI went dark. I have replaced the transformer and the Power Distribution Board (PDB). The input power to the PDB is a solid 240+ VAC. The output from the PDB to the 204v side of the input for the transformer is only 37 VAC.

This is supposed to be around 240v to power the transformer. I have checked everything I can think of - the grounding is good. Even swapped out another PDB in case the one I received was bad. No fix.

Heater is still dark.

Anyone find this issue where the output voltage from the E and F on the wiring diagram is too low (37 VAC) when it should be 240+ VAC?

 

[ajw22]

Welcome to TFP.

@setsailsoon got into the internals of his Jandy heater and may have some thoughts.

 

[setsailsoon]

Jandy JXI went dark. I have replaced the transformer and the Power Distribution Board (PDB). The input power to the PDB is a solid 240+ VAC. The output from the PDB to the 204v side of the input for the transformer is only 37 VAC.

This is supposed to be around 240v to power the transformer. I have checked everything I can think of - the grounding is good. Even swapped out another PDB in case the one I received was bad. No fix.

Heater is still dark.

Anyone find this issue where the output voltage from the E and F on the wiring diagram is too low (37 VAC) when it should be 240+ VAC?

Welcome to TFP. As Allen mentions I've been through the guts of this one in way more detail than I ever wanted to. First thing I'd ask is to check that the small plugin board to change voltage is inserted for 240 or is it accidentally set for 120 vac?

Chris

 

[osopolar3j]

Welcome to TFP. As Allen mentions I've been through the guts of this one in way more detail than I ever wanted to. First thing I'd ask is to check that the small plugin board to change voltage is inserted for 240 or is it accidentally set for 120 vac?

Chris

It is set for 240. Check.

I was able to validate that I can get the correct voltage from the D E F leads going to the transformer. The transformer is not putting out 24 VAC.

I have ordered another one. Even though the I just replaced it - the new one does not seem to be working at all.

Con’t really go further in testing until I can get 24 VAC on the power and ground out of the transformer.

Old transformer has very low voltage out and fluctuates from 20VAC to .1 VAC. Does not hold voltage.

Hoping the new transformer was bad.

 

[setsailsoon]

Not likely the new one is bad. What voltage are you getting on the primary leads to the transformer? Is it constant or fluctuating?

 

[setsailsoon]

Can you post a photo of the power distribution board and the transformer wiring? As I recall the transformer had a floating ground and the primary should have 240 constant when the board is set to 240 v. Sounds like something is not wired correctly. Double check the power connection and the wire connections to the pdb. When you say the power is a solid 240 what does this mean? Have you checked to see if the voltage on the input is constant? Reason I ask is that I was stumped for weeks on this and it turned out to be the problem. Reading was constant but supply wire was leaking tiny amounts of current to ground through tiny pin holes in the insulation to the bare ground wire. Not likely your problem since mine was caused by a direct lightning strike. Learning to me was don't assume anything. A good wire twist connection directly to the main power from the breaker isn't verified power unless you watch a voltage measurement.

By the way, sorry for the delay. Owner build and consulting gig had me overloaded (no pun).

Chris

 

[osopolar3j]

Can you post a photo of the power distribution board and the transformer wiring? As I recall the transformer had a floating ground and the primary should have 240 constant when the board is set to 240 v. Sounds like something is not wired correctly. Double check the power connection and the wire connections to the pdb. When you say the power is a solid 240 what does this mean? Have you checked to see if the voltage on the input is constant? Reason I ask is that I was stumped for weeks on this and it turned out to be the problem. Reading was constant but supply wire was leaking tiny amounts of current to ground through tiny pin holes in the insulation to the bare ground wire. Not likely your problem since mine was caused by a direct lightning strike. Learning to me was don't assume anything. A good wire twist connection directly to the main power from the breaker isn't verified power unless you watch a voltage measurement.

By the way, sorry for the delay. Owner build and consulting gig had me overloaded (no pun).

Chris

It is the main board. Blew the transformer. Replaced the main board and it is working now with a temp board while I procure the correct board with the Jandy flow control.

Thanks for the help.

 

[setsailsoon]

It is the main board. Blew the transformer. Replaced the main board and it is working now with a temp board while I procure the correct board with the Jandy flow control.

Thanks for the help.

Glad you figured it out. That's a little strange though. The MB is powered by 24 vac but I believe signals from it could have caused your symptoms indirectly. Any evidence of black marks on the board or anything else that would have indicated it got hot? Photo's would still be helpful. It's helpful for future problems to get as much info from you on this as we can. We all learn together here.

Thanks.

Chris