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Thread: Help with Jandy LT heater

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    Help with Jandy LT heater

    Hola All,

    Going through the checklist to open my pool recently and finally got to the last item, the heater, which never goes well and this year is no different !

    Heater powers on, flashes the LED to indicate heating and then does nothing else! I have the service flowchart and worked through most of it yesterday until I hit a wall.
    When I got to the section about the fan not coming on (top of page 2) it says to remove the connector from pins F1 and F2 on the Fenwal Ignition Control Module and check these pins for continuity. So I did, and it's open, guide says replace ICM (~$300)

    The flowchart seems to cover the Temp Control Panel and various safety switches fairly well but seems to gloss over the ICM and only mentions the Air Flow Sensor in the sidebar.
    In my search to troubleshoot the ICM I came across several suggestions to jumper the fan on through the black and brown wires (mine are black and blue) that connect to pins F1/F2 of the ICM (which I assume is a relay?) Did that and ICM now powers up and I get an air flow error on the ICM (1 flash on LED).

    So, this is where I'm stuck. I've seen it suggested to jump the air flow sensor out of the circuit but can't see how to do this?
    Would really like to be sure everything else works before shelling out money on parts as I've had trouble in the past with what seems to be almost everything with this unit from the start.

    Any help on what to do? where to go next? (that excludes, as my wife suggests, buying a new heater I looked at the Raypak and they look nice, but OUCH!!! on the $$$$)
    25k gal, IG, PebbleTek w/ attached spa
    2/1.5hp Jandy Stealth pumps
    Jandy DE60 filter
    Jandy/Laars LT400 heater
    Polaris 280

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    Re: Help with Jandy LT heater

    So the blower never kits in and runs? I would kill power to the unit and then remove the top to get access to the blower motor. Then see if there are any obstructions in the way of the motor spinning freely. If it doesn't spin and there is nothing obstructing it, the motor is probably bad and needs to be replaced. If you can spin it, I would then have to look at the run capacitor to see how that looks. It is what starts the motor and keeps is spinning.
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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    Re: Help with Jandy LT heater

    Paul, Thank You for your reply. I believe some of your postings have helped me out in the past

    The blower does in fact run when I jump it through the blue/black wires that are normally connected to pins F1/F2 on the ICM (assume this is just a relay?)
    Another question is what should trigger that relay? as it seems the ICM isn't powered up until the blower is running?
    25k gal, IG, PebbleTek w/ attached spa
    2/1.5hp Jandy Stealth pumps
    Jandy DE60 filter
    Jandy/Laars LT400 heater
    Polaris 280

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    Re: Help with Jandy LT heater

    If you didn't get a voltage reading on F1/F2, it I would consider that the ICM has issues. It another "brain" so to speak that controls a portion of the heater. It will send the signal to the blower and ignitor to turn on. Yes they aren't cheap but look around as you might find one a bit cheaper.
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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    Re: Help with Jandy LT heater

    Looks like a new ICM is in my future Should F1/F2? always have voltage present? If so wouldn't the blower always run? I found a rough wiring diagram for the ICM and it looks like the circuit opens/closes at TH and PS? So I wonder if the problem is the Temp Cntrl not telling the ICM to fire. Even stranger (to me anyway) is with the blower jumped to run the ICM comes to life (and displays an error) where with the blower not running it seems to not be doing anything.

    Finished late last night so may have missed something, will recheck my work this afternoon before I order any parts.

    Very much appreciate your help
    25k gal, IG, PebbleTek w/ attached spa
    2/1.5hp Jandy Stealth pumps
    Jandy DE60 filter
    Jandy/Laars LT400 heater
    Polaris 280

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    Re: Help with Jandy LT heater

    Yes the terminals on the ICM for the blower motor should have voltage on the terminals when you turn the system on. For me I would use alligator clips to each terminal and then to my meters probes, turn the unit on and see what I get. If you have checked all of your safety circuits and they test good, then you have to look at the ICM. ICM seems to come to life as you say only because it shows the blinking light to tell you something else is up. Too me when it blinks as you are describing is telling me that possibly the blower isn't strong enough which could lead me to think the run capacitor is bad but not totally shot. I have seen a motor start up but not running at full RPM and thus causing the error as you describe. You would need an amp meter to read the capacitor to see if it's running at 100%. This is a tricky issue.
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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    Re: Help with Jandy LT heater

    Went back over the whole thing this evening just to be through. Sure enough I get to exactly the same place/step, the circuit is open between F1 and F2.

    Pulled out the ICM and started working backwards from each of those pins (didn't have to go far) and it appears the middle pin of the voltage regulator nearest those pins is open! This pin connects the traces between F1/F2. Flipped the board over to test on the component side and discovered a wad of dead ants between all 3 pins, removed the heatsink and the regulator body looks melted (plastic is bubbled up).

    I saw the warning printed on the board about not attempting to repair it but is there some reason it's not OK to just replace this burnt out regulator? This board appears to be very poorly soldered to begin with (randon blobs here and there) I'm positive I've never done such a sloppy job not even in my HS days!

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    Re: Help with Jandy LT heater

    I guess if you have the time and know how to repair the board you could try it. For me I just throw it out and replace.
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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    Re: Help with Jandy LT heater

    To update, I had a fair bit of trouble locating that voltage regulator (most likely because it's actually a triac! doh )

    I ordered one ($1.73) and will give swapping it out a shot. It's an ON semiconductor triac part # MAC15A8 in case that can help anyone out ever

    Will report back hopefully by next weekend on how it went. Again, Thank You for your help and time
    25k gal, IG, PebbleTek w/ attached spa
    2/1.5hp Jandy Stealth pumps
    Jandy DE60 filter
    Jandy/Laars LT400 heater
    Polaris 280

  10. Back To Top    #10

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    Re: Help with Jandy LT heater

    Got the replacement triac soldered in and everything wired back up this morning.

    Now the fan is constantly on!

    Assuming this may not have worked, Monday, I ordered the ICM from a heater supply place (should arrive today according to UPS)

    I also bought (have not installed) the temperature control for an LX heater (only 1 side of my unit has worked for the last several years and the working side had started to have issues aswell)

    I was told the LX panel is compatable with the LT heater (and that the only difference is the panel)

    Does anyone know if that is infact the case? Searching online I couldn't find an answer( guess I could call zodiac/jandy)

    Thanks again, maybe have a working heater for the weekend! (going to buy plenty of beer to be prepared for either case )

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    Re: Help with Jandy LT heater

    Ignition Control was waiting for me on the porch at 4:30.

    ICM replaced, LX control panel installed about an hour ago.

    Heater is fixed, upgraded and the water is 105!!!

    Opened a bottle of my homemade 2012 merlot going in the hottub

    Thanks Again!

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