Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Boiler kicking off

Options
pahomeowner
pahomeowner Member, Email Confirmation Posts: 3
I have a Crown boiler circa 2003 with a honeywell controller (R7284) on it. I am handy but am pretty new to boilers. We had an issue last year and the HVAC guy had some trouble getting it working again. Ended up replacing the igniter and it lasted about a year, but it's kicking off again.

The errors I am getting are:
NO IGNITION CHECK CAD CELL
and
FLAME PROVEN LATE IN TRIAL

I opened the igniter box and cleaned the cad cell, there was a little bit of grime on it. Starting it up again and it's running again. I'd like to troubleshoot piece by piece just so I don't replace too many things. It got a cleaning about a year ago. Pictures of error codes: https://imgur.com/a/jIvNB5G

With it running, this controller gives an ohm reading. The reading I am getting is around 3100-3200 ohms (see video: https://imgur.com/a/OdOM5r1)

What ohm reading should I be getting? What is that measuring? Hopefully that reading can help me with the troubleshooting.

Comments

  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Options
    You need an analyzer, DMM and a smoke gun.
    Probably a combination of a few things.
    -Boiler dirty
    -Cad cell and/or associated wiring bad.
    -Improper combustion:
    -Wrong draft
    -Wrong/bad nozzle
    -Wrong pump pressure
    -Wrong air adjustment.
    Just for starters.
    Could also be a bad ignitor again, which would happen if you are getting excess heat during/after the run cycle.

    After proper set-up/cleaning, proper draft, true zero smoke, and adjusted for proper air/combustion numbers, Ohms could be in the 300-1200 range. You're obviously in the lockout range so the control is doing it's job-if it's reading ohms correctly. You can confirm that with your meter.

    All in all, it's great to be handy, but smart to get a competent pro in there to troubleshoot.

    There was an error rendering this rich post.

  • sallaberry
    sallaberry Member Posts: 19
    Options
    What fuel is it?
    STEVEusaPA
  • pahomeowner
    pahomeowner Member, Email Confirmation Posts: 3
    Options

    What fuel is it?

    Sorry, it's oil
  • pahomeowner
    pahomeowner Member, Email Confirmation Posts: 3
    Options

    You need an analyzer, DMM and a smoke gun.
    Probably a combination of a few things.
    -Boiler dirty
    -Cad cell and/or associated wiring bad.
    -Improper combustion:
    -Wrong draft
    -Wrong/bad nozzle
    -Wrong pump pressure
    -Wrong air adjustment.
    Just for starters.
    Could also be a bad ignitor again, which would happen if you are getting excess heat during/after the run cycle.

    After proper set-up/cleaning, proper draft, true zero smoke, and adjusted for proper air/combustion numbers, Ohms could be in the 300-1200 range. You're obviously in the lockout range so the control is doing it's job-if it's reading ohms correctly. You can confirm that with your meter.

    All in all, it's great to be handy, but smart to get a competent pro in there to troubleshoot.

    By DMM I am guessing you mean digital multimeter? I'll have to figure out how to use my multimeter to back up the ohm reading that my control board is putting out. Assuming thats good, I will clean it out.

    What is the cad cell measuring? The brightness of the flame? Appreciate the help, looks like your in PA too! Damn oil heat!
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,616
    Options
    @pahomeowner

    Your ohm reading is too high. The cad cell is simple, it's a light sensitive resistor. The more light it sees the lower the resistance the less light the higher the resistance.

    You can disconnect the 2 cad cell wires and hook them to your ohm meter then start the burner. You only have a few seconds because the burner will lock out without the cad cell connected.

    If I am not mistaken, you need to get below around 1600 ohms and should be around 600-700 to avoid lockout

    Dirty cad cell, bad cad cell, cad cell not aimed correctly or burner out of adjustment or a bad primary control.

    You should probably get your service company on this.
  • SuperTech
    SuperTech Member Posts: 2,186
    Options
    Oil heat isn't the problem, it's likely that it's a combustion issue. It's a very straightforward process to troubleshoot and repair if you have the tools necessary to diagnose the problem. It's highly unlikely that you can resolve the matter by swapping out parts. It could just be a matter of performing regular maintenance, like replacing the nozzle and cleaning the flame retention head.
    HVACNUT