Jandy JXI400n Heater Not Working

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charlesas23

New member
Apr 17, 2021
4
Oregon
I have this Jandy JXI400N heater. I bout this house, had a pool guy come out, did a startup inspection and everything checked out. During the startup, some of the pvc pipes were disconnected, probably do to winterization prep. Upon system startup we had some leaks and all the equipment got wet. Once everything was buttoned up, all systems, including the heater, worked. About an hour after the pool guy left, the heater stopped working. Now I get the “Fault Check IGN Steps”
Here’s what I did so far:
-took off heater panels and cleaned out/vacuum the inside
-replace and cleaned (wire brush, etc.) up anything that looked corroded.
-the air/gas mix fan turns on when I turn the unit on to heat.
-the unit clicks three times upon startup, 1 minute apart, just like the forums say.
-with all the external gas flow Valves open, the NG doesn’t flow for whatever reason.

So the questions I have are as such:
1-Does it make sense to check to see if the igniter is not functioning? This unit does not have a site glass. So can I take the igniter out and see if it starts to warmup? Can I attach a voltmeter and take some reading to confirm the igniter is working or not?
2-Is there a possibility that the gas control ON/OFF switch is faulty? If so, how do I check that?

Please help! I have attached the manual’s info for this fault. Thanks.
 

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ajw22 said:
Welcome to TFP.

Check the LED on the Fenwal for blinking.

The water getting on your heater may have caused a flame sensing problem with the grounds.

Heater Flame Sensing - Further Reading

www.troublefreepool.com www.troublefreepool.com

@setsailsoon has experience with water soaked Jandy heaters.

@swamprat69 is always helpful.
Click to expand...
@ajw22 thank you for your greetings and suggestions. I will have to reach out to your recommended user here @setsailsoon . I had a pool repair guy come out today who thought it was going to be the ignition coil, but it was not. He was not happy that I was so inquisitive and had some experience with how things work.

POOL GUY VISIT WORK
Diagnosis-He started narrowing it down and suggested that it may be the heat control unit because he wasn’t getting 24V to the gas valve during the start up cycle.

-He then checked to see if gas was coming to the unit, so he opened up one of the junctions and flow was not a problem.

-Then he said that since the fan turned on, pressure sensor worked, the ignition coil worked, that it was likely that the gas valve wasn’t getting power to open the gas valve. This was “confirmed” by his volt test for the leads going to the gas valve.

-This is where he noted it was likely the Heater Control Unit, since the other startup items appeared to be working properly.

-Me being inquisitive, I asked if he thought we needed to replace it and I wrote down the model. Apparently he didn’t like that I started looking up the item online. He then told me that if he knew that I was intending to have him just diagnose the problem and I would replace it myself, that he would have never made the service call. I never said to him that was I was thinking of doing, but he was already mad at this point, collected his service fee and left.

What I did after he left
-During the startup cycle, I checked the voltage going to the gas valve and when the heater clicked, I got a 1 second burst of 24V going from the heater control unit to the gas valve.

-Nearly instantaneously, the voltage basically dropped to 0. That would happen two more times as the startup cycle conducted its typical 3 attempts to startup.

-The first time I tried to troubleshoot this problem I noticed that the plate that covers the gas valve ON/OFF switch was a bit rusty.

HERES WHAT COMES TO MIND FOR ME
#1-I am not getting the gas valve to open on the unit
#2-possible problem with the switch/gas valve unit
#3-possible issues with the heating control unit
#4-(most likely) I am missing something because I don’t understand how the heater works.

***BIGGEST ISSUE SO FAR
Knowledgeable Jandy repair technicians are no where to be found here. This guy was “supposedly” one of the only ones who is familiar with Jandy equipment in the great Portland area.

ANY HELP IS GREATLY APPRECIATED HERE

Thanks,
Charles
 
When you say all of the equipment got wet, did any of the electronics get wet (power interface, user interface, Fenwal ignition control or gas valve itself? If so how wet? It looks like you pulled your troubleshooting attachment from the "installation and operation manual" so I assume that you have that. This seems to be the listed fenwal ignition control for your heater Jandy R0456900 Laars LXi Heater Ignition Control If needed we can go over the "sequence of operation" so that you can check it with a multimeter on start up. Trial for ignition (24v power to gas valve) as listed on the fenwal should be 7 sec. , not 1 sec.. If you get no ignition in three tries the red led on the fenwal should flash three times.
 
If you get the gas valve to open initially it indicates you would have passed all of the safety tests. I've never seen the 1 second duration as Swamp indicates I've only seen 7 seconds or none. Could be a connection at any of the sensors that wiggles to a "no go" state. This would stop the ignition process. How many red flashes on the Fenwal after shut down?

Chris
 
That's why I was asking if any components got wet and how wet and for photos. If charlesas23 is actually only getting 24V to the gas valve for 1 second it would seem to indicate a problem with poor gas valve relay contacts in the Fenwal which may or may not have been caused by a problem with the gas valve itself. As a test, I would recommend removing the brown wire(s) from the gas valve (thereby removing the load) and measuring voltage between the removed brown wire(s) and the yellow wire(s) remaining on the gas valve during a try for heat. If you then get 24V for seven seconds with no load you can pretty much pinpoint it to poor relay contacts under load. You may still have a problem with the gas valve. You could check that by creating a direct 24V circuit to the gas valve that is fused for the gas valve amp draw, If the fuse blows when connected to the gas valve it would show that you have a problem with the gas valve also. It is very dicey trying to reuse either electronic components or gas valves that have been exposed to flooding or a lot of water. Safety first!
 
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charlesas23 said:
@ajw22 thank you for your greetings and suggestions. I will have to reach out to your recommended user here @setsailsoon . I had a pool repair guy come out today who thought it was going to be the ignition coil, but it was not. He was not happy that I was so inquisitive and had some experience with how things work.

POOL GUY VISIT WORK
Diagnosis-He started narrowing it down and suggested that it may be the heat control unit because he wasn’t getting 24V to the gas valve during the start up cycle.

-He then checked to see if gas was coming to the unit, so he opened up one of the junctions and flow was not a problem.

-Then he said that since the fan turned on, pressure sensor worked, the ignition coil worked, that it was likely that the gas valve wasn’t getting power to open the gas valve. This was “confirmed” by his volt test for the leads going to the gas valve.

-This is where he noted it was likely the Heater Control Unit, since the other startup items appeared to be working properly.

-Me being inquisitive, I asked if he thought we needed to replace it and I wrote down the model. Apparently he didn’t like that I started looking up the item online. He then told me that if he knew that I was intending to have him just diagnose the problem and I would replace it myself, that he would have never made the service call. I never said to him that was I was thinking of doing, but he was already mad at this point, collected his service fee and left.

What I did after he left
-During the startup cycle, I checked the voltage going to the gas valve and when the heater clicked, I got a 1 second burst of 24V going from the heater control unit to the gas valve.

-Nearly instantaneously, the voltage basically dropped to 0. That would happen two more times as the startup cycle conducted its typical 3 attempts to startup.

-The first time I tried to troubleshoot this problem I noticed that the plate that covers the gas valve ON/OFF switch was a bit rusty.

HERES WHAT COMES TO MIND FOR ME
#1-I am not getting the gas valve to open on the unit
#2-possible problem with the switch/gas valve unit
#3-possible issues with the heating control unit
#4-(most likely) I am missing something because I don’t understand how the heater works.

***BIGGEST ISSUE SO FAR
Knowledgeable Jandy repair technicians are no where to be found here. This guy was “supposedly” one of the only ones who is familiar with Jandy equipment in the great Portland area.

ANY HELP IS GREATLY APPRECIATED HERE

Thanks,
Charles
Click to expand...
I'm having exactly problem that you are describe on my LXi heater. The front header was cracked in the last Winter storm in Texas; I have the bypass installed on the heater while ordering a new part. Once the header replaced, the heater was turned on and working fine for about 1 hour and stop with the IGN control Fault. I just let it reset and tried another day; it did started up fine and died out after 1 hour for about 10 more times. However, it won't start up now; it go through the whole ignition process, the gas valve is clicked opened, the burner does make some startup noise but died out right away. I also checked and found the 24VAC at the brown wire for only about 1sec.

Have you able to make anymore progress on your heater? Thanks
 

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