Help Jandy JXI 260N Frustration!

[setsailsoon]

Folks,

Sorry for the long note but I think the details are important for this weird problem. Prior to this problem my heater worked flawlessly and was used extensively over past 5 years for spa and keeping the pool perfect since we swim year-round 3-4 times per week.

Several months ago I had a stupid mishap that splashed a cup of water on the control raceway on it while operating. There was a loud pop, flash and it was dead. So I set about troubleshooting per the manual. It was clear I had fried a lot of components just from looking at the "forest fire" appearance of the boards. Here's the process I went through so far:

• Power distribution board was all burnt up. So I replaced it.
• Not sure if blower was operational so I powered with 240v and it worked. Phew!
• Manual control panel display was still dead so I checked and found no power to it from the universal control board.
• Removed transformer and bench test showed it was producing 24+vac intermittently only, seemed to work only on one angle if wiggled just right. So I replaced it.
• Universal control panel now worked. But ignition cycle would not proceed to open gas valve. So I checked all the safety circuits (limit switches, fan pressure, high temp vent) and no errors. Bypassed each with no luck. Temp did confirm below set temp (86 deg Vs 104)
• Ignition control did not seem to be functioning so I replaced (bought unit on eBay)
• Replacement unit worked but was faulty because it was opening the gas valve but not supplying power to the igniter (very dangerous!)
• Returned for refund and replaced from a pool heater store. This unit was brand new in OEM Jandy packaging.
• Now the heater worked perfectly... or seemed to.
• Went all the way through the ignition cycle lit the burner. Yes! shut it down and declared success. Heater wasn't really needed since here in S Florida water was still 88-92 deg F with solar only by late afternoon.

So now a few weeks later I wanted to heat the spa for evening relaxation. Used my new Intellicenter app control to start it. Everything worked well except after about 6 seconds flame went out. So now a second set of troubleshooting actions:

• Unit tries to light 3 times. Goes through the proper ignition cycle including purge, preheat, gas valve open. But closes right at 7 seconds. After 3rd attempt unit shuts down and displays "check ign steps".
• Fenwel control has 3 flashing lights
• Since safety circuits all test good (no change when bypass) and voltages test good. I start to suspect a problem with the flame sense circuit. I measure voltage on the two pins with insulted miniture pin clips and sure enough the voltage goes up during the flame but no where near enough (about .150 vdc instead of 1-2 v.) Definitely increases as soon as flame ignition but just not high enough for the ignition control to keep the gas valve open. Can't tell through the sight glass how big the flame is but it definitely does light.
• So I go down the bad sensing rod trail. Sensing rod and igniter are the same item on this model so I replace the igniter.
• No Joy. Exactly the same behavior. 7 second flame then shut down.
• Next I remove the burner tube to inspect. Looks great! Just a very fine layer of dark brown soot-like material. I sand with fine grit paper just in case and replace. Still No Joy.

I'm now grasping as straws. Will try a manometer test to see if my gas pressure has somehow coincidentally dropped. But this has worked flawlessly for 5 years and my 22KW whole house standby genset works fine on the same supply. Other than this only thing I can think of is the blower was damaged and is running but not at proper speed. Any other ideas out there from you experts? @JamesW ,@Jimrahbe @ajw22

Any ideas would be much appreciated.

Chris

 

[ajw22]

Lets call in @ps0303 @Pool_Medic @swamprat69 @kadavis

 

[setsailsoon]

Thanks Allen!

 

[setsailsoon]

Update, I made a water manometer and tested. Got 5" with burner running, right on spec. So narrowing down to blower motor. Thoughts?

Chris

Manometer before heat is on:



Manometer while burner is running:

 

[swamprat69]

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.

 

[setsailsoon]

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.

I have removed, cleaned, and replaced all of the green and yellow grounding wires I could find. I'll check again. Surprisingly, none of the ground wires I found had any visible corrosion but I cleaned with a wire brush anyway. Even added an extra ground from one of the fan flange bolts directly to the ground gang on the frame next to the ignition module. No change. Maybe I missed one so I'll check again.

Thanks for the reply.

Chris

 

[setsailsoon]

Folks,

I'm thinking about running a test by leaking a 2+ micro-amp on purpose to ground from the igniter wire directly to the ground connection on the Fenwel ignition sensor. Seems like I could use a 50 mega-ohm resistor in series with a diode to accomplish this. If I make the connection right after the valve opens and the unit continues to run then I've confirmed the ignition module is indeed functioning correctly. Make sense?

Chris

*** I edited this post to correct the math on the resistor. I will need approx 50 M Ohm not .5 M Ohm as originally posted.

 

[ps0303]

So the ony parts not replaced so far on the unit are the gas valve, all of the safety limits, and the blower?

 

[setsailsoon]

So the ony parts not replaced so far on the unit are the gas valve, all of the safety limits, and the blower?

Yes, and not too bothered because I had proven each of the parts replaced were fried from my stupid mishap. Out of desperation I replaced the gas valve yesterday. No joy, exact same behavior (ouch!). I also ran 24 vac directly to the "W" terminal to trigger continuous demand for heat. So that would eliminate any sensors. Still exact same behavior. I'm thinking it must be some bad contact in the ground system which I've checked as best I can or the blower is not running at speed. I've cleaned the burner tube and added a grounding wire from the blower flange bolt (that's in direct contact with the burner) directly to the yellow ground wires that connect to the ignition module to ensure any flame sense current is detectable. So I'm thinking I'm not detecting flame sense since there may not be sufficient flame. Weird I know but I'm pretty short on options.

Have you ever heard of a blower running too slow? Capacitor maybe?

I plan to build a breadboard quick circuit to tie into one leg of the igniter that will intentionally leak 2.5 micro amps dc to ground. My thinking is that should force the gas valve open if the ignition module is working properly. So the flame must be too small and then the blower is the only thing I have that could increase the flame. My circuit will cost a couple of bucks so worth it before I shell out another $300+ on the blower.

Thanks much for your reply... not a lot of takers on this weird problem!

Chris

 

[swamprat69]

I am assuming that you have the installation/operation manual for your heater- https://www.jandy.com/-/media/zodiac/global/downloads/h/h0574300.pdf From looking at it it seems that you have a specific gas offset pressure that you are supposed to be running at ( see section 4). As to trying to force flame proof, realize that 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. Here is some info on the ignition control- https://www.burnerignitionmodules.c...58871469624590DS_35-66-EN_F-35-66.pdf....part configuration at the end of this should give you the individual specs for your specific ignition control

 

[setsailsoon]

Swamp,

Thanks so much, yes I have the docs you linked. I haven't checked the offset pressure although it should be doable with my home made manometer. Good idea to confirm, I'll do that.

On the flame sense signal, my plan is to wait for the gas valve to open then switch the ground leakage circuit on. It appears I have 7 seconds. Does this approach make sense to you?

I had no idea burner control had changed to flame sense. Pretty neat technology and from what I can tell must be very reliable normally even though they are only detecting a couple millionths of an amp. Amazing!

Thanks for the reply, as you can see I'm learning a lot.

Chris

 

[swamprat69]

With a "forced combustion blower" design similar to the Trane Voyager commercial pkg. rooftop units that has the gas supply fed into the combustion blower the gas valve is a negative pressure gas valve meant to be set from what I see in the Jandy manual at -0.2" WC.

 

[swamprat69]

It might be helpful to use a digital differential manometer when trying to set the gas pressure as -.2" WC might be hard to get adjusted with your setup. A digital differential manometer is also useful for checking air conditioning airflow by using the total system static pressure drop and the blower performance chart to make sure that you have 400 CFM per ton of AC with the specific filter that you are using. Dropping below 400 CFM per ton has a negative impact on system performance, so trying different filters until CFM per ton starts to drop below 400 CFM per ton will give you optimum performance for your system. I have always used UEi digital manometers ( basic is less than $100).

 

[setsailsoon]

Swamp,

Thanks so much. I love it when I have a good excuse to buy a new tool! My wife has been pretty impressed with the results of TFP expert advice on our pool so far with swg, borates and a gorgeous pool for a fraction of what neighbors are paying. So all I have to do is tell her a TFP expert said I need this!

I'll post the readings after I get the new manometer. Most of the parts for my milli-amp leak circuit came and I hope to have it working tomorrow.

Your help is much appreciated!

Chris

 

[swamprat69]

Looking at your last post, most flame rectification sensing is measured in microamps not milliamps

 

[setsailsoon]

Yep good catch. I keep mixing them up. I meant micro amps (millionth of an amp). 2-2.6 seems about right. Got my 50 mega ohm resistors today. This leakage is so small I don't think it would trip a GFI breaker... amazing!

 

[setsailsoon]

Swamp,

I'm trying to figure out how to measure the speed of my fan since I'd like to verify it's not at speed before I buy another one. Thinking about using a Fourier Transform of the frequency generated by the fan to get the speed. I haven't done this math for 45 years but there's an easy way to do it with Excel now. I'll need to know how many blades are on the fan. I can take it apart to count them. Do you by chance know how many blades are on it?

Chris

 

[swamprat69]

I don't think you need to be worried about the combustion blower Rear'y. because if it was not working correctly you would not close the normally open contacts on the air pressure switch and put power to the pressure switch proving terminal (PS) on the fenwal ignition module to start the ignition sequence. If you wanted to check the combustion blower Rear'y, just use a multimeter to check the 8mfd/370v ( + or - 5%) capacitor under the end cap of the motor and make sure that the running amps are under the listed full load amps (FLA) on the motor nameplate.

 

[swamprat69]

Duh...Rear'y really means Rear'y.

 

[swamprat69]

I can't type assembly... it comes out Rear'y