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Carlin 40200 Primary Control Lock Out

muftobration Member Posts: 9
edited December 2019 in Domestic Hot Water
Hi Folks

In October, I bought a home with a domestic hot water tank with a Carlin EZ-1 burner on it. It’s been working fine, but today the primary control locked out and I can’t get it to come back on. On the primary control, the red Lock Out LED is lit, no other lights. On the thermostat, the green Power On and amber Call for Heat LEDs are lit.

Pressing the red reset button on the primary control doesn’t do anything. If I press and hold for any amount of time (tried up to 80 seconds), nothing happens. When I kill the power and turn it back on, the green Flame Sense and amber Self Test LEDs light up, then the green one goes out after a couple second, then the amber one goes out and the red one comes on after a couple more seconds.

I’m a handy homeowner, not a professional, so I am not sure how to begin troubleshooting this issue. I would appreciate any advice!

I attached a picture of the control locked out.

I took a video of me resetting the thermostat to show what the primary control does as well: Dec 07, 12 20 09


  • muftobration
    muftobration Member Posts: 9
    False alarm! I got it running again. I had to push the red reset button MUCH harder than I was, to the point where my thumb hurt. When I pushed it hard enough it followed the reset procedure described on the under side of the primary control: the amber light came on after 10 seconds and off after 20. I let go and the burner ignited.
    HVACNUT Member Posts: 4,187
    Well Mr. Handy Homeowner. I'm sorry to say, You're Fired! All you did was unlock the control (which the steps for doing that are underside of the primary for a reason. Only Pro intervention) after three failed trials for ignition. There's still the case of why the burner went into safety in the first place.
    Time to call a Pro. There are way too many things that will cause a burner to go into safety.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,301
    edited December 2019
    Not False alarm! If your burner went out on safety it's because your primary control sensed an unsafe condition.
    Best to have a competent pro come check it out.
    Also, very important...pushing the reset has never fixed a burner problem. In fact it could make it worse. Specifically by spraying unburnt oil into the combustion chamber. A few resets, without firing, and you're well on your way to building a bomb, and making a mess.
    It's important that only your service provider should push the reset button as what happens when the burner restarts and fires could give valuable clues as to why it went off in the first place.
    Newer primary controls have some diagnostics on them.

    Edit: Seems like @HVACNUT and I were typing at the same time...
  • muftobration
    muftobration Member Posts: 9
    Okay, thanks guys. That’s good advice. This was the second time this happened. The first time was a few weeks ago, shortly after its annual service. Should I wait until it locks out again before calling a pro? I’m worried that if I call while it’s running fine, they would not be able to recreate the lockout condition and I’d have wasted my money on a service call.

    Also, the first time it was in lock out (weeks ago), I didn’t hit the reset button to get it back on. I killed the power and turned it back on. Is there some reason a lock out would be forgotten after a power cycle? When turning the power on, the heater made no attempt to fire. The motor didn’t run or anything.
    HVACNUT Member Posts: 4,187
    Call a reputable company and set up an annual maintenance and also let them know there is a preexisting condition. And we all know what that means. JK. Just make them aware so it can be addressed and "hopefully" diagnosed as anything other than needing maintenance.
    Using pressure and vacuum gauges, ohms meter, combustion, draft, smoke tests, a good tech should be able to find the issue.
    While on the phone, make it known you want a printed combustion report when the work is completed.
    And other than necessary maintenance parts (nozzle, filters, strainer), if a part or control is needed, what is the company's guarantee, parts and labor, for that part and repair.
  • muftobration
    muftobration Member Posts: 9
    Just to put a bow on this conversation, I did end up calling for service and it was resolved. The tech replaced the CAD cell and assembly, according to the invoice (I was at work at the time of service). I've had no problems since.

    I will add that I actually checked the CAD cell myself while troubleshooting and concluded it was working fine. The spec said it should read >50KOhm in darkness and <10KOhm in a normally-lit room. It was open in darkness and ~300 Ohm in a normally lit room. I didn't check the assembly, though (not sure what that is), so it could be that that was the culprit and the CAD cell was replaced at the same time because it's cheap enough.
  • muftobration
    muftobration Member Posts: 9
    I realize this is an old thread now, but I have an update. The burner locked out again. I called back the same company, since it was just 4 weeks ago that they came and did the service where they replaced the CAD cell. I was suspicious of that repair for the reasons I cited above. They charged $56 for the CAD eye and some kind of associated assembly, but no service fee, which was nice.

    This time they replaced the control board itself. Hopefully that's it because they said it would be a $200 part. I haven't received the bill yet to verify. It's only been a day now, but so far so good.