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Thread: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

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    Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    My Hayward H250 pool heater was working this weekend but then it started to issue smoke and smelled like burned plastic. The top of it now has black soot on it.

    It won't go on any more and I get a service light & LO error code.

    The pool flow is very strong so I don't think that's really the problem.

    Any help/advice is appreciated.

    Thanks,

    - G

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    Re: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    Have you opened up the front cover? I am willing to bet that something is clogging up the flow of the exhaust gas and has caused the burners to vent out the front of the burner chamber. Sounds like maybe a rollout switch has tripped as well.
    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: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    danpik,

    Thanks for your reply. I really appreciate it.

    I checked under the front cover. Everything seems ok. However - I did find something else, but I'm interested in your opinion. I took apart the panel that's got the little bread-board with all the transistors on it and the LCD. Behind the bread-board was this giant ant nursery. It was just all black with ants on it. I'm surprised the thing even said, "LO". I've cleared out all the ants and put everything back together. But I still get the LO message. Do you think a concentration of ants might have messed something up?

    It was all running fine during memorial day weekend and I got the pool up to 82. Later that same day, the burnt smell started. Then the smoke. Then LO. Do you think I might just be out of propane? I don't know how to read the gauges on the tanks. They're a little cryptic.

    -G

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    Re: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    Ok - I took things apart all the way down to the heat exchanger - which is all sooty. It turns out that the thick cottony-type matting around it was burning. I'm thinking that perhaps water flow got really low but the flow switch didn't trip. So surrounding matting started to torch.

    I think the heater is otherwise ok and water runs through it nice and strong. No leaks or anything. But is there a way to reset all the switches and have it try again? What else do I need to do?

    G

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    Re: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    you will need to use a volt ohm meter to check out the suspect switches to see if any of the are open.
    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: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    Ok. Plz 4give my dumb questions.... So for example, if I'm checking the flow switch where do I put the voltmeter leads? e.g.: right on the flow switch leads directly? And what should I expect my voltmeter to do (get zero or give a number)? And what's good/bad? Let's say it's the "bad" flavor of reading, then what do I do to make the switch reset itself?

    I'm really a total noob here but I'm not afraid of technology and willing to try stuff.

    Any help is appreciated.

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    Re: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    danpik - your last reply gave me enough to go on and try some productive next steps. So thank u again. Despite my extreme noobiness, I was able to jump each switch one at a time using some insulated clips. I didn't electrocute myself TG....

    I narrowed it down to the temperature limiter kit. Once I closed that circuit the heater lit.

    However, the flames quickly became intense and began lapping out from under the firewall. I turned the thing off before it melted and I went back to my manual.

    I've never touched the gas valve ever but somehow it was open to max - which resulted in a large flaming.

    It's now down enough that it looks to be working correctly. But I'm guessing that I need to replace the temperature kit.

    How do you decide how much to open or close the gas valve? Is there a way to figure out the sweet spot?

    Thanks,

    G

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    Re: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    If the flames are kicking back towards the front, then you need to clean the heat exchanger. That's why the limits tripped. They were doing their job.

    To clean the heat exchanger, turn off gas, shut off electric to the unit, you pull the burner tray out, remove the top of the heater to get at the heat exchanger. Take a house and spray water from the top down and then set the top back on and then spray up from where the burners where to get the bottom of the heat exchanger. Do this a few times from the top and the bottom. The soot is nasty and will sit on top of the water as it comes out. Get it on yourself and clothes and you will be cleaning for a while. Once the heat exchanger has been rinsed off, clean the burners with a wire brush. Then reinstall and hook it all up and try turning on the heater again.
    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: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    Ps303,

    Will do. How much water pressure should I use (the full jet, somewhere in between)?

    So if I clean the exchanger, are you saying I can/should open the gas valve back up to max?

    What about the temperature limiter switch kit? Is there a way to reset it back or is it damaged and I need to replace the entire kit?

    -G

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    Re: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    G
    sorry, I was away from my computer most of the day. As Paul mentioned, you need to clean the heat exchanger. The gas shut-off valve is supposed to be in the completely open position. It is not to be used to regulate the gas pressure/flow to the heater. The powered gas valve in the heater and the air venturies are what control the air fuel mixture. If the heat exchanger is clogged then the air flow thru the heater is not correct which is causing the problem you are having. Please do not run the heater with the safety devices bypassed. As you have discovered they are in place for a reason.
    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: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    It doesn't matter too much on the pressure. However, the higher the water pressure coming out of the hose could cause the soot to spray back at you. Usually the limit on the left has a small button in the middle of it between the two wires connected to it that you can push in and rest the limit. If it doesn't have one or if after you clean the heat exchanger and reset it, you still have an issue with the limit, replace it.
    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: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    Point taken on not operating the unit with safety switches overridden. I stood by watching it the entire time so I could make a detailed assessment of the unit "in motion" and snap some photos that I might post here if need be.

    For the sake of any who may read this seeking info, the temperature limiter switch has a little button thingy that looks like a hollow bit of tiny copper tubing. It's a button. You can press it to reset the switch and at least test to make sure everything is working ok and determine if you need to buy replacement parts or not. Mine seems to be doing its job so I won't be buying parts.

    More news once I clean the exchanger and wire-brush the burners.

    This has been a real learning experience so thanks for all the great input.

    -G

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    Re: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    Some of the limit switches used today do have that reset feature. Some don't. I keep a hand full of them at the ready as here in the northeast when a heating boiler acts up (flame rollout) it is usually on a Sunday afternoon when it is going to be 10 degrees over night.

    The most likely cause of the heat exchanger sooting up, is trying to heat water that is too cold. This causes condensation which the soot particles in the flue gas stick to and start to build up. Somewhere in your heater manual, it may warn against this. They might have a min water temp that is recommended before firing up the heater.
    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: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    Ok, I finally got some time to go back to my heater and clean the soot off the exchanger with a hose. Then I wire brushed the burners as instructed. I reassembled everything and I'm pleased to report that my heater is working just fine now. And yes, I turned the gas valve back up to max and it's burning without a problem.

    1,000 thank you's for all the help and advice. I learned a ton and saved a bundle of $$$.

    Much appreciated,

    -G

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    Re: Hayward H250. Smelled burnt plastic. Smoke & Soot. Now get LO error.

    Awesome!

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    Chris
    TFP Moderator Chris V. ~16K Pool & Spa, 48NSF DE, IG Plaster Circa 2000, Intermatic PE653, Challenger pump with a 2 speed B2984, 20gal stenner chlorine injection, Houston, TX
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