Jandy JXI won't ignite

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gnr5

Well-known member
May 28, 2019
221
Miami, FL
Hello there! I have a Jandy JXI that was working up until a few weeks ago. I'm replacing the igniter but didn't notice anything wrong with it.
When the heater comes on, I hear the click, and like the flames are trying to come on but then it stops. Then it tries again for 2 more times and then get 3 flashing red lights. While I wait for the replacement, anything else I could check?

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Do you smell gas out of the exhaust when it tries to ignite?

Do you hear any whosh of it lighting?
 
If you get a puff of heat from the exhaust, then you may have a flame sensing problem. Heater Flame Sensing describes what may be happening and ways to fix it.

@setsailsoon dived into that problem with his JXI heater. He documented it in...

Help Jandy JXI 260N Frustration!

You would think I was on a phone texting with autocorrect
www.troublefreepool.com www.troublefreepool.com
 
gnr5 said:
Stupid question, and I know I got a lot to read, is the igniter different than the flame sensor?
Click to expand...

The flame is sensed through the ignitor to ground. You need to make sure that all the grounding connections, screws ,wires and wiring terminals are clean in order to get a good flame signal.

The ignition control is at first providing 120v to the ignitor and after a specified time for ignition dropping out the 120v to the ignitor and looking for proof of flame through a different circuit.
 

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Yes, correct, propane, still have the same 500 gallon tank and got the correct regulator. The heater was working since 2021-ish when I posted that.

Its dark out but I did manage to check the ground connections and found these two pretty dirty. The one on the board is clean

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Heater Flame Sensing - Further Reading

www.troublefreepool.com www.troublefreepool.com



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Ignition Control Kit

Ignition Control: Provides energy for ignition, monitors fl ame quality and controls the gas valve. Uponcall for heat, the blower is activated to purge the combustion chamber. Electrical power is then applied to thehot surface igniter. When ignition temperature is attained, the gas valve opens and ignition occurs. If stablefl ame is detected the igniter will power down. If stable fl ame is not detected the control system will close thevalve to prevent further gas release. If a total of 3 ignition attempts fail an ignition fault is displayed.

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The Fenwal has two test points for flame current FC+ and FC-. Flame current is the current that passes through the flame from sensor to ground.

The best way to measure the flame sense current is with a true RMS meter. Measure the current with a good true rms meter that can measure dc current in the microamp range.

To measure flame current, connect a True RMS or analog DC micro-ammeter to the FC+ and FC- terminals. Readings should be 1.0 µA DC or higher. If the meter reads negative or below "0" on scale, meter leads are reversed. Reconnect leads with proper polarity.

If you don't have a RMS meter you can just test for voltage between FC+ and FC- terminals to confirm if you have flame sense. Each micro-amp of flame current produces 1.0 VDC. For example, 2.6 VDC equates to 2.6 µA. Voltage is an indirect indication but easier to do with typical DIY equipment. But it's still very difficult to measure unless you make up some pin wires to clip your voltmeter to. Or you can order some insulated micro clips for the test.

The reading should be 3-8 volts and this corresponds to the millionth's of an amp signal your flame sense signal should reading. If you try to check this be very careful since you can easily short the 24 vac circuit which can blow the transformer before the 2 amp fuse blows.

When not operating, the flame current should read 0 volts dc and 0 microamps dc. DC amps and voltage should be zero when there is no flame.[6]
 

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After the ignition cycles and try's 2 more times with light flashing 3 times means the Fenwal is not detecting current leakage to ground. The amount of leakage is micro amps and difficult to measure. Here's what seems to be the culprit in order frequency that I've seen posted here and other sites:
  • Corrosion - you can verify this by running a separate new wire from the flame detection probe to a ground that's known to be good near the burner. Pentair actually makes a kit for this purpose that can be used on any heater. They all use almost identical flame detection control. The wire will have to connect in a place that gets extremely hot so it needs to have that silicone high temp insulation. This is what's supplied in the Pentair kit.
  • Power supply wire insulation integrity. If there is any leakage from the hot wires to ground coming in to your unit this will interfere with the flame detection signal and cause the Fenwal to flash 3 times. This is almost impossible to test since only tiny amount of leakage makes the flame detection system inoperable. You may think this isn't likely but in my case a lightning strike caused tiny, pin tip-sized dots along the supply wire insulation. Before you give up run a jumper wire outside the conduit, disconnect the original wire and connect the jumper. If this works remove the original power supply wires and replace with new conductors. To my amazement this worked and solved the problem for me. I spent weeks trouble-shooting and devising bizarre ways to test every component in the system and every component eventually proved good. Before I gave up and just bought a new unit I figured the power supply was the only thing I didn't prove had no leakage to ground. It did have the correct voltage. We sold the house but the original heater that I replaced the power wire on is still working.
  • Low gas pressure is causing a weak flame that isn't strong enough to cause ionized gas particles to produce micro current to ground. This is almost always caused by a valve that's been accidentally closed and/or out of propane.
  • The fenwal and gas valves are incredibly reliable so they rarely fail, especially when you are getting 3 red light flashes. This means all the safety devices are working to get you though the heavily protected, complex ignition sequence that gets you to the step where the gas valve opens. The Fenwal is also working to get this far in the sequence. They are also very expensive. The control board can also fail and it's expensive too. If it fails there's normally some burnt spots you can see. This happened on mine after the lightning strike but the unit still wouldn't work until I replaced the power wires.
Good luck and I hope this is helpful.

Chris
 
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gnr5 said:
Before I buy the pentair kit, would it hurt to try cleaning the corrosion off from my ground wires I have. You can see in the picture it is corroded.
Click to expand...
Not at all! You can also just try an ordinary wire to see if this fixes the problem. Just don't leave it in there as the insulation will deteriorate quickly.
 
Also another easy thing to do is to remove and replace all the wire connections on the Fenwal. It only takes a tiny amount of corrosion to interfere especially on the ground connector. The nice thing about this flame detection technique is it's incredibly safe. It's also very susceptible to corrosion related failures and a few other quirky things that cause false ignition faults.
 

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