Help diagnosing Jandy LXI heater, Ignition fault error, Fenwal air flow fault with single blink red LED

[jthom86]

Hello, I hope there's a heater expert that can help me here!

I'm trying to diagnose a customer's Jandy LXI pool/spa heater. Customer says the heater doesn't work. On visual inspection, the heater is in good repair, minor wear on the outside of the unit. Wiring and plumbing are clean and leak free. The heater is wired for automation into a Hayward ecom4 and was set for remote thermostat, but for testing purposes I have disabled it and am operating it manually. On the heater, spa mode is selected and the temp is set to its max 104F.

Visual inspection of the heater from the inside is like new, with minor oxidation and some bug carcasses/leaf debris. Wiring and hoses are clean and free of damage. Board is clean and shows no damage. Gas valve has white oxidation on the outside, peculiarly more than anything else in the unit.

When starting the variable speed main pump and letting it rev up to operating RPM of around 2600, the heater kicks on. The heater blower starts up. After a few minutes, the heater shuts off with the "Ignition failure fault" error. I confirmed the gas valve on the external pipe is parallel and the knob inside the unit on the valve is set to on. I confirmed the igniter is in like new repair. The Fenwal blinks with a red LED one time, indicating an air flow fault.

I tested continuity on the air flow switch by placing probes on the leads going into the switch, then blowing into the tubes attached to it. When blowing into the tube from the burner pipe enclosure, I had continuity. When blowing into the tube from the side, there was no continuity.

I never smelled any gas in the entirety of testing. I tested with the external gas valve in both positions, and never smelled anything, however I checked the gas meter when it was in the open position and the meter was moving.

I don't know what else to test, I'm hoping one of you with more experience can help point me in the right direction.

If you need photos or additional info, let me know.

Thank you!

 

[ajw22]

Welcome to TFP.

Test if you get 24V at the gas valve. If not, the heater is never getting to open the gas valve before it throws the Air Flow Fault.

You could have a failing blower motor that is not getting up to speed and giving enough air pressure to engage the Air Flow Switch.

Check that no rodents got into the blower area and blocked air flow.

@swamprat69 may have ideas.

 

[jthom86]

You could have a failing blower motor that is not getting up to speed and giving enough air pressure to engage the Air Flow Switch.

The blower starts up fine, and I did test the air flow switch while it was running. It had enough to engage it. When testing for 24v on the gas valve, should that be constant, or only during the ignition?

 

[ajw22]

When testing for 24v on the gas valve, should that be constant, or only during the ignition?

Constant.

24V keeps the gas valve open. No volts, no gas.

 

[swamprat69]

How did you test the airflow switch? With a differential manometer? If the blower starts up, you should have 24V between "W" and "GND" on the Fenwal. If you then don't have 24V between "PS" and "GND" on the Fenwal, either the pressure switch is not closing because of insufficient airflow ( airflow can be measured with a differential manometer and checked against the listing on the airflow switch) or the airflow switch is receiving sufficient airflow and the switch is bad or there is an open circuit in the associated wiring. You should not be blowing into the airflow switch as you could damage the diaphragm by causing excessive pressure.

 

[swamprat69]

You said that you get a 1 blink fault code at the Fenwal. That is an airflow fault code and you would not start the ignition sequence by putting 24V to "PS" on the Fenwal and powering the ignitor for the 40 sec warmup nor get 24V between "VAL" and "GND" after the warmup.

 

[jthom86]

I haven't been back out to this job yet, but I was looking around and I think I may have found the issue.

On my posted photo above of the fenwal, the wiring for PS and FS seem to be reversed, based on this diagram I found:

 

[swamprat69]

So you are saying that the "IGN/FS" and the "PS" wires are switched at the Fenwal? In that case you would be putting 24V from the closed contacts of the pressure switch to the flame sensor circuit which is not active until the end of the sequence of operation when the Fenwal checks for flame rectification, and you would have no voltage from the flame sensor wire to the "PS" terminal since it is an open circuit with no flame present "if you have a separate flame sensor and are not sensing through the ignitor" and would show as an "Air Flow Fault". Just confirm the wiring and switch the wires back as no damage should have been caused.

 

[jthom86]

I went out to this pool today and switched the wires on the Fenwal. It definitely was wired incorrectly. I started the pool pump, and the heater blower started. No air flow fault, and it went into the next phase of trying to ignite. The igniter came on, but no gas.

Looking through the sight glass, I confirmed the igniter was glowing. I checked for 24v between VAL and ground during the time it was trying to ignite. I measured 0v, however every 15-30 seconds or so there would be a click sound from the Fenwal and I would see voltage increase for a split second, then go back to 0v.

There is a relay inside the Fenwal that I assume has gone bad which would explain the click and voltage spike then back to zero. The manufacturer says to replace the entire $200+ unit. Most likely for a $1 relay.

 

[JamesW]

Note: Information is for Research Purposes only.

No advice is given regarding repairs.

The Manufacturer Says that the board is not repairable. Printed on the board.

Only do what you know you can do 100% safely based on your own data, information, knowledge, research etc.

SPA heater, what would happen?

I share other picture for further reference. Are the dark spots dirt or burn marks?

www.troublefreepool.com

The top box is probably the blower relay.

The black box on the right might be the valve relay.

The blue box is the ignitor relay.

@JamesW, the blue relay is SMI-S-224L

https://www.tme.eu/Document/725ab589eca79b03aadf80d634a9ee5a/SMI-datasheet.pdf

The blue relay coil should get 24 VDC after the blower starts.

You can see if 24 VDC closes the relay.

Are you getting 24 VAC at TH to GND?

@JamesW as you mentioned, the ignitor relay is not working. I remove it and tested with a power supply (24VDC@100mA) and not current neither contact switching happened. It seems the internal coil is damaged.

I will check the voltage on the board to be sure is powering the relay coil.

I found a relay replacement locally and installed it a few minutes ago.

The voltage in the ignitor is now 120V (with a true RMS meter).

 

[JamesW]

The red dot is the ignitor relay.

 

[JamesW]

SMI-S-224L SANYOU - Relay: electromagnetic | DPDT; Ucoil: 24VDC; Icontacts max: 8A; SMI | TME - Electronic components USA

SANYOU SMI-S-224L | Relay: electromagnetic; DPDT; Ucoil: 24VDC; Icontacts max: 8A; SMI - This product is available in Transfer Multisort Elektronik. Check out our wide range of products.

www.tme.com

 

[jthom86]

Thanks JamesW

I believe the issue is with the valve relay since there's no voltage to the valve. I ordered a replacement

 

[jthom86]

Today I replaced the valve relay but still have the same issue.

The relay clicks on after around 30 seconds, but only has 6-8 volts instead 24. It goes back to 0v after a few seconds, and this process repeats a few more times over the next 3 minutes. The igniter lights up each time and is visible from the sight glass.

I measured 27v on the red wire going into 24VAC on the Fenwal.

Here is a video of the issue:

Is there anything else beside the Fenwal that could be causing this issue?

 

[jthom86]

Could this be due to one of the Temp Limit fusible links?

I read on google a solution to a problem with similar issues, he stated

"So, it ended up being an "open" vent box fusible link, I used quotations because it was not an OL open, but just enough resistance that it would not throw the "Fuselink fault" I should have known better LOL."

One other symptom I noticed was sometimes (maybe 1 out of every 5 attempts) when starting the heater, the blower would start up and at a random time, would completely shut off. It would then start back up and try to go through the ignition phases.

 

[jthom86]

I replaced the fuse link on the bottom by the blowers. I wasn't able to get the blower to start after this. Even after replacing the original fuse link, I didn't have blower action.

Only when I jumped the 2 black wires on the PIB, for the high limit, I was actually able to get the blower running, and the gas kicked in, and the heater started.

I think I need a replacement on the high limit circuit.

 

[jthom86]

Got this replacement for the high limit harness for cheaper than the individual sensors. I'll replace it tomorrow and update.

 

[jthom86]

Final update: I got this heater running The existing high limit sensor was rusted out and broken off inside the socket. Not sure why the fault wasn't coming through on the heater UI, but after testing voltage across the pins on the control board for the high limit switch, only getting about 6v through the sensor, I suppose it didn't fail enough to give the fault. Next time I'll check all these sensors first, even if there isn't a code or clear fault on them.