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Thread: Laars LLD Heater Won't Ignite

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    Laars LLD Heater Won't Ignite

    I have the very popular Laars LLD heater. Until today it worked fine since I last replaced some parts 2 yrs ago. But today it does not ignite. The igniter glows - three cycles. And there's the usual click sound while the glow is at its peak. But no ignition and no gas odor. The 500 gal. propane tank is nearly full and the valves are both in on position, of course. I always thought that click was the gas valve turning on, but no gas flows. Could it be the flame sensor - assuming that sensor also senses when the igniter is up to proper temperature?
    23k gallon ig concrete pool, 1hp hayward pump, 36 sq ft de filter, old hayward 350 gas heater
    Philadelphia, PA

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    Re: Laars LLD Heater Won't Ignite

    A hot surface igniter system uses the igniter as a flame sensor as well. The fact that the gas valve "clicks" as you say it does tells me the ignition circuit is working OK. The lockout is happening because there is no flame present. make sure that there are no closed valves in the propane line. Is it possible that there is something wrong with the pressure regulator? I am not real familiar with propane tanks.
    Unknown make 18' above ground (bought used in 1999) Sparco sand filter. Hayward 100,000 BTu heater. 2 speed pump

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    Re: Laars LLD Heater Won't Ignite

    Thanks Dan - it's interesting that you say the hot surface igniter is the flame sensor as well - because I cannot find a separate flame sensor. HOWEVER, the Laars tech support guys say there is one: Teledyne Laars R0334300 Pool Heater Flame Sense Rectification Kit - and on several pool heater parts websites they have it available - from $125 to 200!.
    For example: http://www.parts4heating.com/product-p/r0334300.htm
    And they say it's part of my Laars LLD model - But like I said, I can't find anything like this in my heater.
    As for the propane line - it's definitely clear.
    23k gallon ig concrete pool, 1hp hayward pump, 36 sq ft de filter, old hayward 350 gas heater
    Philadelphia, PA

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    Re: Laars LLD Heater Won't Ignite

    Just looked at the schematics for this. I see no flame sensor circuit shown. In fact I don't ever recall a HSI system having a separate flame sensor. I do know that some systems look at the current draw from the HSI to determine if the valve can be allowed to open or not. Most house ovens use this system. The HSI will glow but not pull enough current to satisfy the board to allow the valve to open. I do not think your heater uses this though. Try firing up the heater again and hold your hand on the gas valve. See if you can feel the "click" when you hear it as it may be something else (not sure what) that is clicking. You don't hear any gas hissing after the click or smell any? Wondering if the orifices are plugged up.
    Unknown make 18' above ground (bought used in 1999) Sparco sand filter. Hayward 100,000 BTu heater. 2 speed pump

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    Re: Laars LLD Heater Won't Ignite

    How did you check the propane line?

    If the gas valve indeed makes a click sound and you never smell propane, then you either have a bad regulator or the gas valve is indeed bad. To check, you need to verify that you have propane flowing to the regulator and after. Before the regulator there should be a shut off. Shut it off and then you should be able to disconnect it from the regulator. Once disconnected, open the valve slightly and see if you can hear and smell propane. If yes, then shut off and reconnect everything and then you need to find a spot after the regulator to disconnect the pip between it and the gas valve. Do the same thing, shut off gas, disconnect, open shut off, check for gas.

    A HUGE word of caution while doing this because if there is any type of spark or flame while checking, the propane will ignite.

    Laars had an issue with using the igniter as the flame sensor so they added the Flame Sense Rectification Kit to clear up this 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: Laars LLD Heater Won't Ignite

    Thanks Paul! Your last sentence explains the mystery as to why the Flame Sensor uses the words "rectification kit", and why I don't see that part on my heater!
    There are hex screws on both sides of the gas valve and another kind advisor said I need to measure the gas pressure at those 2 points with a manometer. So I've got a plumber coming to do that. Thanks again!
    23k gallon ig concrete pool, 1hp hayward pump, 36 sq ft de filter, old hayward 350 gas heater
    Philadelphia, PA

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    Re: Laars LLD Heater Won't Ignite

    And thanks to you again, Dan. Yes, I do feel the valve when it "clicks". So it seems to be something with the gas line. Your advice really helped get me to this point!
    23k gallon ig concrete pool, 1hp hayward pump, 36 sq ft de filter, old hayward 350 gas heater
    Philadelphia, PA

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    Re: Laars LLD Heater Won't Ignite

    How long has it been since this unit ran? It is posible tha spiders got into the orifices on the feed tubes to the burners and plugged them up. This is quite common on propane appliances as they love the smell of propane
    Unknown make 18' above ground (bought used in 1999) Sparco sand filter. Hayward 100,000 BTu heater. 2 speed pump

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    Re: Laars LLD Heater Won't Ignite

    I use it several times per week - and the day before the current issue arose.
    23k gallon ig concrete pool, 1hp hayward pump, 36 sq ft de filter, old hayward 350 gas heater
    Philadelphia, PA

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    Re: Laars LLD Heater Won't Ignite

    The plumber didn't show.
    I became convinced the valve is bad.... So I took it out, reconnected the wires while holding i. Turned on the pump and heater. When the HSI glows and the valve "clicks" I can see that the valve doesn't open. So I ordered a replacement. We'll see ...
    23k gallon ig concrete pool, 1hp hayward pump, 36 sq ft de filter, old hayward 350 gas heater
    Philadelphia, PA

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    Re: Laars LLD Heater Won't Ignite

    No luck! The new valve installation did not do it. ****. I'm out of ideas. Paul, Dan - any ideas?
    Again, when the HST is glowing bright orange for like 10 sec., there's a click and the wires to the valve show 30 VAC on my meter for about 6-7 seconds, but no ignition and another click and the voltage drops to 0 as the HST cools off.
    I'm fairly ignorant re elec circuitry, but seems to me the gas valve getting that electricity is the final step in the ignition process. Gas pressure is definitely on the intake side. Spiders or other are not the prob, as I cleaned out everything when I had the burner assembly out to change the valve. This is a true mystery.
    23k gallon ig concrete pool, 1hp hayward pump, 36 sq ft de filter, old hayward 350 gas heater
    Philadelphia, PA

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    Re: Laars LLD Heater Won't Ignite - SOLVED!

    The new valve from Honeywell came with some extra parts. One was i conversion kit (just a spring, really) to change it from natural gas to propane. The other was a "wire harness" - really a simple connector. I originally installed the new valve without this connector - just connected the wires the same way they'd been on the original valve. But when I added the new connector it worked !!!
    Thanks again, Dan and Paul!
    23k gallon ig concrete pool, 1hp hayward pump, 36 sq ft de filter, old hayward 350 gas heater
    Philadelphia, PA

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