I have a Jandy JXI heater, model #400. Upon going out to start it up I noticed I had no power to the User Interface Board. I then began checking for power. I had 120v to the Power Supply Board and 120v out to the transformer. I then checked power from the transformer to the fuse holder and had nothing. I ordered a new transformer and when it arrived I noticed it was for a LXI but the specs on the old and new transformers were identical so i installed it. I checked for power and now had 25v(+-)from transformer. All good except now everytime i power up my system (heater and pump on same breaker) the 2amp fuse blows. I’m guessing I’ve got a short somewhere. Where should I start looking. I called a HVAC outfit and they want $220 for the service call and $250 per hour plus parts. I think i better learn how to fix this. It doesnt look that complicated. Thanks in advance for the advice.
Jandy JXI power issues
- Thread starter olypool
- Start date
- Jul 21, 2013
- 65,443
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
You have a multimeter and know how to check continuity?
Find the wiring diagrams in the manual and see what is on the 24V circuit.
Examine all the wires for signs of rodents chewing on the wires or insulation chafing.
Disconnect all the sensors from the board and see if the fuse blows with nothing connected to the board.
You have to use a process of elimination to pinpoint the area with the short.
@swamprat69 may have ideas.
Find the wiring diagrams in the manual and see what is on the 24V circuit.
Examine all the wires for signs of rodents chewing on the wires or insulation chafing.
Disconnect all the sensors from the board and see if the fuse blows with nothing connected to the board.
You have to use a process of elimination to pinpoint the area with the short.
@swamprat69 may have ideas.
I do have a multimeter. Yesterday I found a Jandy JXI technician troubleshooting manual off of Dohenys site with detailed step by step testing instructions with target values. Thank-you for your advice. I do appreciate it.
I have done some further testing with the multimeter. I have discovered 130v coming into Ignition Control (L1-L2) and only 6volts coming from ign/120 gray and ign/fs black. This would tell me that the ignition control box is bad. If the ignition control box is bad could it be responsible for blowing the fuse? I removed the leads from the hot surface igniter (with power off), inserted a new fuse and turned power back on. The fuse blew again. I’m a little baffled and need to sort out the information I have. Anyone have an idea what’s happening here?
- Jul 21, 2013
- 65,443
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
You are looking int he wrong place for the cause of the 2A fuse blowing.
The 2A fuse protects the 24V control circuit powering the PIB and Fenwal.
You are poking around the 120V circuits that power the igniter. That is not connected with the @A fuse.
- Jul 21, 2013
- 65,443
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
swamprat69
Well-known member
Do you have an above ground pool with a 120 volt power supply to the heater? I am guessing that the fuse that you are blowing is in the 24 volt transformer secondary circuit. This would have nothing to do with the actual power circuit to the ignitor as this ignitor power circuit is initiated by a 24 volt relay in the Fenwal ignition control and the power to the ignitor only goes through the relay contacts. This should be the manual for your heater https://cdn.fluidrausa.com/-/media/...4300.pdf?rev=01b8b9d803f54b69b2729c8fb3935b16 The electrical connection diagram is on page 31 and the manual states that it should also be on the inside of the heater door. In the 24 volt circuit of the Fenwal, nothing happens until the main board sends a 24 volt hot (ungrounded) signal to the "W" or "TH" connection on the Fenwal. You can disconnect the wires at The "24 VAC" and the "W or TH" terminals on the Fenwal and if the fuse still blows the problem is not with the Fenwal or ignitor. If the fuse still blows we can continue on from that point.
- Jul 21, 2013
- 65,443
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Any of the sensors shorted to ground will blow the 2A fuse as will a short int he gas valve. I have highlighted to circuits in yellow. I would disconnect all of them from the PIB and see if the 2A fuse blows with all disconnected.
If the 2A does not blow then connect them one at a time and see if you can identify which sensor is blowing the fuse.
If the 2A does not blow then connect them one at a time and see if you can identify which sensor is blowing the fuse.
Thank you all for your input. Swamprat69, my pool is in ground and yes, the 2a fuse is directly from the 24v side of the transformer. Ajw22, Tomorrow I will follow your instructions regarding sensors. Now, swamprat69, should I disconnect the 24v and the W or TH terminals on the Fenwal before or after doing the sensor test recommended by ajw22 or does the sequence matter? Again, thanks folks. I’m learning and I really appreciate the help.
swamprat69
Well-known member
Feel free to follow Allens recommendation as it is just another way of going about the troubleshooting. I will chime in if I feel that I can be of any assistance.
Ajw22, Today I disconnected all sensors indicated in yellow and turned power back on. (Does water temp sensor have anything to do with this because I did not disconnect it?)The fuse blew. I then disconnected the board from power at the j3 connector, installed a new fuse and turned breaker power back on and the fuse did not blow. I then did the test swamprat69 recommended and the fuses also blew (with the board plugged back in). I did check power at the L1 and L2 of the Fenwal and got 129v. I then checked power at the incoming leads to the Hot Surface Ignitor and only got 20v. Not the 105-120v. I did a continuity test on the Ignitor and got 48 ohms which I believe indicates a closed circuit but I do not know for sure what the Ohm value should be. Is it possible that I have two separate issues, one being a bad board and the other being a bad Fenwal?
Will you please see my response to ajw22 regarding testing done today. Thank-you.
Is this scenario plausible; The transformer fails on the 24v side then the PIB goes and lastly the Fenwal? Possible or simply coincidental? Bad luck?
swamprat69
Well-known member
Probably not 2 seperate issues. Please show a well detailed photo of your "universal controller power interface board".