Featured Jandy JXI heater transformer issues after surge / short repair

chrisleeotten

Member
Apr 27, 2015
10
Spring, TX
Looking for some ideas on this problem I'm running into. At this point it's getting really expensive. Background. I had some sort of surge or short when it appears water from a HEAVY storm may have splashed onto both of the incoming 120va wire caps inside the heater. One of the caps was visibly wet.. I’m not sure it was the cause but it was suspect. The breaker had also flipped. The main board also had a roasted slug on it, but no burn marks. After some testing determined the Transformer and the Power Distribution Circuit Board had blown, I’ve included some pics so you can see. I was hoping that was the extent of the damage. After installing the replacements I had power, LCD, but during the startup process the igniter would not get hot. Ok, so the Fenwal Ignition Controller must also be bad. Next I picked up a “used” Fenwal Ignition Control off amazon at a nice discount. Installed that, and everything fired up and all appeared to be great and we had heat.
24hrs later, I try and fire up the heater and during its startup process the new transformer melts down and burns up with white smoke. I have a replacement transformer on the way, but I’m looking for some suggestions on what could have caused my new one to burn up. I assume either the “used” Fenwal Ignition Controller is faulty and pulling too much amperage on the transformer, or the main board is faulty. It’s really strange that it worked for 24hrs and even fired up. The fact that it did not melt down until I turned on the heat makes me suspect the used Fenwal I purchased. I guess it’s possible that all of this was caused by the roasted slug and not the water… ugh. I don’t know.


I’ve included pics of the carnage and one of the main board complete with roasted slug. I’ve also included a bonus pic of the faulty Fenwal Ignition Controller opened up so you could see. I wanted to avoid replacing the main board, but as expensive as these transformers are I think I may need to replace the Fenwal with a new one, and the main board. Basically the entire setup. Thanks for any tips!
 

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setsailsoon

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Oct 25, 2015
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Chris,

Boy, I hate to hear there's somebody that may have fried their Jandy Jxi electronics as bad as I did! Mine might still have been a little worse. I actually dumped about 2 cups water directly on the tray that holds all the boards and this was after a lightning strike surge.

Back to yours. I hate to agree but it sounds like everything got fried again. Mysterious to me is you don't mention a blown fuse. There's a 2 amp fuse that should prevent all the carnage you've incurred. Have you checked and was it possibly bypassed or something? Reason I ask is my fuse didn't blow either until after I fried two transformers I changed it out for a real 2 amp fuse. Turns out my transformers were doing a great job of protecting the fuse.

Other thing to mention is I went the eBay and Amazon route for some of the parts. Turned out to be a bad choice for me as well but at least the Amazon people did refund my money. I found parts4heating.com to be a decent discount and they are an authorized rep for Fenwal so you can get warranty replacement if the unit is bad from the factory (service tech at Fenwal told me this does occasionally happen).

Chris
 

chrisleeotten

Member
Apr 27, 2015
10
Spring, TX
Interesting you mention the fuse... Yea it appears to be fine and looks perfect. I thought the same thing, "What is the point of this fuse if it can't protect the transformer?". Did you just fully replace the entire fuse setup for a new 2amp fuse?

So those pictures of the Power Distributor Board, and Fenwal were from the first surge event. The new PDB and Fenwal still look perfect. Only the transformer cooked this time. I'm curious do you think the new Fenwal is suspect for causing the transformer to blow, or could it still be the main PIB board "that had the slug on it". I can return the Fenwal. I would really like to not spend $300 on the PIB main board but at this point it seems pretty difficult to tell what board is causing the transformer problem. The Power Distributor board still looks perfect. That Dang slug that got cooked on my PIB just makes it my second suspect. Thanks man!
 

setsailsoon

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Did you just fully replace the entire fuse setup for a new 2amp fuse?
I did end up replacing the housing because one of the connections was damaged and broke. If your fuse housing is in good shape I'd just replace the fuse with a real fuse. Get a good brand like Buss. You can probably get one at an auto parts store... get a few of them. It's easy to accidentally short to ground when you're trouble shooting. After I replaced my fuse I never had the transformer blow before the fuse was fried.

I'm curious do you think the new Fenwal is suspect for causing the transformer to blow, or could it still be the main PIB board "that had the slug on it". I can return the Fenwal.
I'm puzzled as to why the heater could run and heat and then after 24 hours it smoked your transformer. The secondary is very low amperage so for the transformer to smoke and burn it must have been the primary that failed. This would also explain why your fuse didn't blow. I would check the 24 vac circuit and the high voltage all the way through to be sure you don't have a dead short somewhere in the system before you fire it up again. Almost sounds to me that you have a high voltage wire somewhere that is shorting. Check all the HV wires carefully to see if there are any loose connections or wires with burned insulation that is shorting.

Chris
 

chrisleeotten

Member
Apr 27, 2015
10
Spring, TX
Now that you mention it. Looking at the burned transformer it does appear to be cooked from the blue wire area. I’ll check the incoming power and double check the voltage coming from the new PCB. Very strange for it to burn up only when it tried to fire up. I figured the transformer would not be getting any extra strain other than those two boards. I’ll even check the incoming power outside of the unit. The fact it worked once had me really confused as I would think if the boards were bad it never would have worked the day before.
Will report back tomorrow when I can take a look. Is it safe to send power to the heater without having the transformer installed just to check the PCB for the correct output? I would assume so. Thanks for the tips man! I’ll pick up some fuses also just in case it’s the 24va stuff causing it.
 

setsailsoon

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Will report back tomorrow when I can take a look. Is it safe to send power to the heater without having the transformer installed just to check the PCB for the correct output? I would assume so. Thanks for the tips man! I’ll pick up some fuses also just in case it’s the 24va stuff causing it.
The pcb you're talking about is the one below right? It's powered by 24 vac so you shouldn't have any power to it without the transformer. Sounds like you somehow have a dead short in the system so anything could be hot. Exercise caution when you mess with it if you have the power on.

Chris

1589856953741.png
 

chrisleeotten

Member
Apr 27, 2015
10
Spring, TX
Sorry, I was referring to the Power Distribution board. The board that sends power to the transformer. Was going to test that out without having the transformer attached. I think you may be right that it's in the 120va side of things. Considering that everything hooked up to the 120/240 side of things burned up during the fist surge, I'm wondering if my short is in the blower. After some research there is a large capacitor that can be replaced on the blower. I'm guessing that capacitor may be damaged. Didn't even think of the other things attached to this Power Distribution Board.

Power Distribution Board in pic below just for reference. That left harness is labeled Fan/Blower. Would make sense as the blower kicks on in startup and may have caused the burn down. I also have no idea if that true hahahaha.
51Sb1igrKXL._AC_.jpg
 
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setsailsoon

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It's not easy to test the capacitor and the fact the blower ran 24 hours earlier would lead me to think it's OK. You can power it up separately to verify with a jumper. But do check the capacitor and other potential places for a dead short. There must be a short somewhere.

Chris
 

chrisleeotten

Member
Apr 27, 2015
10
Spring, TX
Well.. No sign of any shorts I could find. I looked back at my old burned Power Distribution board. The line that was burned was from the black incoming 120va leading to the transformer. Soooo, if you look at what else that black incoming 120va connects to on the other side of that Power Distribution board, it's the blower. That capacitor is $20 bucks so I'm going to replace it and take that out of the equation. It physically looked ok, but was not sure how to test it with it holding power potentially. Looking at the old burned Ignition Fenwal Board. The capacitor is what burned down on the board as well. Maybe all the high voltage capacitors went down or were damaged on the surge. Will report back just in case it works to help others. Will also be getting a new fuse. Wish I could easily protect that transformer on the high side as well... hmmm

If this does not work, not sure I want to buy a new main board next. May just replace the heater.... ugh. Thanks!
 

setsailsoon

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I would power the blower directly. I was able to do that and confirm my blower, saved almost as much as the board. I believe it runs on 120v and can confirm that. I just made up a jumper to connect to an extension cord. Worked like a charm. Doesn't sound like your blower is the problem to me.
 

SDor

Well-known member
Jun 14, 2018
78
Chicagoland
Well.. No sign of any shorts I could find. I looked back at my old burned Power Distribution board. The line that was burned was from the black incoming 120va leading to the transformer. Soooo, if you look at what else that black incoming 120va connects to on the other side of that Power Distribution board, it's the blower. That capacitor is $20 bucks so I'm going to replace it and take that out of the equation. It physically looked ok, but was not sure how to test it with it holding power potentially. Looking at the old burned Ignition Fenwal Board. The capacitor is what burned down on the board as well. Maybe all the high voltage capacitors went down or were damaged on the surge. Will report back just in case it works to help others. Will also be getting a new fuse. Wish I could easily protect that transformer on the high side as well... hmmm

If this does not work, not sure I want to buy a new main board next. May just replace the heater.... ugh. Thanks!
Bad motor capacitors rarely cause surges/shorts. At least with AC motors. Not sure what the Jandy has, but welcome to the blown PDB club. I just replaced my 2nd PDB/transformer in 4 years. This time, I wasn't positive the transformer was bad, but I didn't want to risk blowing my new board to I replaced them both. I'm going to have to do some deeper investigation into the root cause because I'd rather not do this again for a while.
 

chrisleeotten

Member
Apr 27, 2015
10
Spring, TX
Sdor, on yours check the location of the two incoming 120VA wires and where those are attached to the PCB red and black. On mine they were pointed down rear the bottom vents. So a heavy rain could splash water up into the vent and possibly cross/arc those lines. Sounds like this will be a fun system for years to come haha.

Once the capacitor shows up I’ll just go ahead and install it to be sure. But I’ll do another round of investigation for shorts. I did read on AC / Furnace blowers that the capacitor could cause a transformer meltdown. But yea, may not be it at all. It’s a 370VA capacitor so fairly decent power. I was thinking even if the capacitor was damaged that the blower may still run underpowered and potentially cause problems. Thanks again guys! Learning a lot here
 

setsailsoon

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Chris,

Thinking a little more about your situation. First let me explain why I persevered with my heater. As I think you've discovered they aren't all that complex. They have a couple expensive parts like the PIB, blower, gas valve, tubes. Once I knew my gas valve, blower were good I could replace everything else and it would still be less than half the cost of a new heater. My heater was only 6 years old so I was pretty sure the tubes were fine. It was a huge struggle to prove the components and I got a LOT of help here but I finally narrowed it down the power supply and it turned out a lightning strike or my blunder dumping water on the electronics had caused tiny holes in the insulation that caused leakage to ground, It was only a tiny leak so everything ran fine except the leak was enough to interfere with the flames sense signal that is only a few millionths of an amp. Not even enough to trigger a GFI. How weird is that? I rigged up an independent power supply and the heater worked perfectly immediately. We used it all winter and still top off the solar with an hour or two make the water "wife friendly" several times per week. It never fails. They are simple units and I'm very certain yours will "give it up" sooner or later and way lower cost than a new unit. So hang in there buddy!

Here's the way I see your unit in terms of what works and what doesn't:
  • You ran the unit long enough to prove the gas valve is fine.
  • You ran also ran it long enough to prove the PIB was good at least 'till you fried the new transformer. But it is suspect since it's "downstream " of the transformer.
  • It's very hard to believe the blower would work then fry due to a transformer that's not even in the same circuit.
  • Capacitors are cheap enough that you can just replace it so I would.
  • The used Fenwal does connect to the 120v circuit. I got one that was definitely bad from an online vendor. So I would look at it very carefully. I hated opening them because you almost have to break it to get it apart. But I would in your case to inspect the board close to the 120v connection and the igniter power wire.
Are you running on 240 or 120 v? I would switch to 120 v (I did this during my trouble-shooting). This way you can get a cheap 24 vac transformer that doesn't have the middle leg on the primary. These are readily available at HD in the irrigation section or online. I'm not sure how the electrical works on that 3 leg transformer but it seems they use that middle leg to get 120v to supply the 120 v to the components that need it (blower and Fenwal). Nothing in the heater uses 240 v. Nice thing about this approach is if you blow the transformer it's $20 not $100. Then test your blower with and extension cord to 120 v supply and an adapter (very easy to make and I did this too). Once you prove these I would power up with no power to the Fenwal or the PIB. I suspect it's something else like a short that you haven't found yet. It seems your failure mechanism was water in the power connectors or on the power distribution board that may have burnt some insulation that allows an arc to ground somewhere. Those wires snake through holes to get to their destination. I'd check them very carefully to see if there's a burn mark anywhere . If you power up and it there's no pop wiggle the wires with insulated gloves on to be sure it's not a wire. If this doesn't cause the failure I'd plug in the Fenwal and restart. If that doesn't cause the failure I'd try the PIB. Worst case your still less than half the cost of a new heater. And most likely you won't replace anything expensive unless it's actually bad.

I hope this is helpful.

Chris
 

chrisleeotten

Member
Apr 27, 2015
10
Spring, TX
@setsailsoon , This is all REALLY good information. I went back and read your story and repair process. Feeling inspired, I'm on a mission now! Quick question. I'm going to run a new 120v circuit to the heater and pull new wire through and everything. Would a standard 15amp breaker work at the panel? I can't find any details on the amperage required for 120v setup. Why do they default these things to 240v, is that slightly more efficient or something? If it blows the transformer after this, I agree, it's the Fenwal or the PIB. At least the Transformers are cheap after going to 120v. Really appreciate you taking the time to help me out on this! Going to 120v was not on my list, and I'm not seeing any downside to it. Great idea

-Chris
 

SDor

Well-known member
Jun 14, 2018
78
Chicagoland
They probably default to 240 because most pool pumps run 240 and most heaters and pool pumps are on the same circuit.

Also, thanks for the tip on the pigtails. When I re-wired the new board and transformer, I did make sure they were up high in the cabinet with the wires running down from the cap to minimize the chance of water exposure, but I didn't think to look prior to the install. I *probably* wired it the same way last time, but you never know. I do stupid things sometimes.
 

ajw22

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Jul 21, 2013
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They probably default to 240 because most pool pumps run 240 and most heaters and pool pumps are on the same circuit.
Actually you should never have your pump and heater on the same circuit breaker.

But many pool electrical subpanels only have 240V to it and it does not create a need to run a 120V neutral line to the subpanel.
 

chrisleeotten

Member
Apr 27, 2015
10
Spring, TX
@ajw22 interesting. I’m not at home to check. But I know this heater is on the same circuit as my waterfall pump. Rarely would run those together “if ever” but makes me wonder how that sub panel is setup. I’ve also have not run my waterfall since has all happened. Hope that it’s still ok also. Ugh