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Oil burner relay

BT123BT123 Member Posts: 11

Hoping someone can help. I have a fairly new furnace that heats my home through baseboard/radiant heat. Just a few days ago, I woke up to a cold home due to the relay tripping on the Honeywell Ignition control (R8184 D). So, I pushed it back in and it ran for about a minute then popped again. I waited about 15 min and it fired up and ran until it reached its' target temp (180 F). Everything seemed fine. It ran for a few hours. We left the house and when we came back, the relay was popped again and the temp gauge on the furnace was all the way down to 60F. I started it back up and it got back up to operating tempo again. Last night (sometime while we were sleeping) it did the same thing again. I also have an Aquastat Relay Type 8 . The oil burner I have is a Beckett Model AFG. ...O, I have also inspected the cad eye and didnt see any damage or dirt on the lens. Any advice would be GREATLY appreciated!



  • bustoff315bustoff315 Member Posts: 26

    When you first pushed the reset button and it only ran for a minute, did the burner ignite? If it did, then I think you can pretty much narrow your problem down to the control or cad cell. If it didn't ignite then there are many other things that could possibly be wrong why it keeps locking out like a plugged oil filter or pump strainer.
  • BT123BT123 Member Posts: 11

    Yes, it ignited. So the cad could be bad without any visual imperfections? What is the control your talking about? Is that the Aquastat Relay...the box that connects to a pipe on the furnace? Or is the control, the Honeywell Ignitor?

  • bustoff315bustoff315 Member Posts: 26

    Yes, it's possible for the cad cell to be bad without any visual imperfections but it's also possible the R8184D control is bad also. If it ignited and went out around a minute, it sounds like the control didn't pick up the signal for flame which indicates either a bad control or cad cell eye and wire.
  • BT123BT123 Member Posts: 11

    So, do you believe I should start by replacing the cad cell....then if it still trips, replace the control?

    Thanks Again
  • earl burnermannearl burnermann Member Posts: 126
    check ohms

    Next time it goes down get your multi meter and disconnect the two wires from the ff terminals of the safety relay. Restart the burner and check your ohms. If it's reading 1600 ohms or better then the eye is not seeing the flame properly. They sometimes start giving you random problems when the ohms reach around 1100. If your ohms reading is below 1000 then I'd say it is the cad cell relay. If it usually runs up to temp and goes off after running awhile it could be other things such as a clogged oil delivery system.
    If the women don't find you handsome, they should at least find you handy!
  • icesailoricesailor Member Posts: 7,265

    I don't disagree with anything said. 

    Before you go out and buy a new cad cell, when you have the transformer open and the nozzle assembly removed, stick your hand down the tube and run a finger around the inside of the center opening. If you feel any carbon buildup, or see any by looking down the tube, scrape it off with a used copper fitting brush. That has always been the #1 cause for nuisance lock-outs for me.

    If you are not skilled in the nuances of oil burners, when you re-started it and it ran for "1 minute" (more like 45 seconds) and stopped, you may not notice if the ignition was sparking, which sounds like "scratching". Sometimes, you don't hear the Scratching at first (delayed ignition) and then, starts. You don't hear the scratching. Carbon is an excellent conductor of electricity. If the carbon buildup in the center hole of the retention ring gets big enough, it can let the spark go to ground through the carbon. After a while, it can burn out the carbon and the spark will go back to the other electrode. While the burner is running, it may make new Carbon on the retention ring. It is worse on the outside (inside the chamber side). If you feel it, remove it.

    There are some things that you learn from experience and a sense of awareness.

    There are a lot of troubleshooting tips that are too numerous to mention here.

    Another cause for burners going on safety is a bad motor. It doesn't start but shuts down before the motor overheat relay cuts out. The fact that it ran for 45 seconds and then cut out usually precludes that. When and if you remove the nozzle/electrode assembly, slide it out carefully, DO NOT loosen the weird screw on the left side of the burner and hold it horizontally until you gat it out. Then, with something to catch the oil, turn it vertically with the nozzle pointing UP and see how fast the oil runs out. If it "drips" out, change the nozzle, pump strainer and filter. The nozzle strainer is clogged and the nozzle orifice isn't getting full pressure. It will cause carbon buildup on the retention ring. In MY experience.

    In my years of being in business, nothing made me feel as stupid as I did when I changed out an expensive part and came to find out it was a simple problem that didn't need the expensive part.

    Just my experience and opinion.
  • BT123BT123 Member Posts: 11
    I checked the

    ohms on the cad cell and it read: around 40.0 when I covered the eye up and 0 when I put a bright light on it. I didnt see any carbon on the housing for the eye either. Does this mean its good? I looked and felt around in the area where the electrodes are and didnt see or feel hardly any carbon. Maybe the R8184 D is bad? It hasnt tripped since sometime last night. When I went to bed it was fine, then woke up and it was locked out again....its been fine for about 5 hours now. Thanks again for the advice!
  • icesailoricesailor Member Posts: 7,265
    If you're clever:

    If you're clever, you need a short piece of thermostat wire to jump put the "F-F terminals on the 8184 control. Here's how I check it. Disconnect the cad cell wires from the F-F terminals and connect the thermostat wire on ONE side with the other side ready to connect. Take the multi-tester leads and wire nut them to the two yellow cad cell wires. The meter should read "open". Start the burner. It will start. As soon as the burner starts and flame is established, connect the other end of the u-shaped thermostat wire to the other F-F terminal/This will keep the burner running and the Multi-tester should be reading what the eye is seeing for resistance. If it is 1600, it's not the eye. If it is 1,000, the eye is OK. If it is 600 to 1,000. it is probably OK but it needs other playing around but you should have an analyzer and know what you are doing.

    Describing your symptoms, I'd be looking at a new motor that isn't getting enough starting amperage all the time. You could put a analog Amp-Clamp on the motor leads but when I get to that point, I change the motor.

    I don't ever remember having a bad cad cell. But plenty of cad cell holders where the cell wanted to fall out of the socket. I replaced the whole thing with a new cell assembly that includes the new eye.

    What you did by shining a light on the eye and covering it up just shows that it "sees", when it isn't running. It's what it "sees" while running that is important.

    They stopped making that boiler in the 1970's. If the burner motor is as old as the burner/boiler, change the motor.

    There are a few things I left out. You should understand them before you start.
  • WeezboWeezbo Member Posts: 6,232
    justa thought ,

    i noticed some carbon build up on the stack at the adjustable 90 and then i wondered, 'what if...?'

    have you had the stack off recently to clean it?

    and when it is running is the bottom side of the stack above the adjustable 90 cooler or only warm to the touch in comparison to the top side of the pipe?

    that is an indication of soot buildup in a stack..

    the cad is the problem if it keeps doing that buh the reason it is doing that is because it would be seeing soot at times ... May be ? ...

    that is possible cause and effect and reason and even though the cad may be good the soot makes it preform somewhat erratic ...


  • BT123BT123 Member Posts: 11
    Thank you everyone

    For the advice. It was the cad cell. I wiped it clean and ensured it was plugged in properly. it works fine now.
  • icesailoricesailor Member Posts: 7,265
    Cad Cell:

    It shouldn't be dirty. Something is wrong and the boiler needs to be cleaned THOROUGHLY.

    That is a cold start boiler and cold start control. It is chock full of kibbles and bits.

    Beckets don't like back pressure, and a dirty boiler will cause back pressure.

    When was the last time anyone had an analyzer on it and when was the last time anyone had the top cover off to look in and clean between the sections? Time for the soot saw. Be careful that you don't knock the boiler putty out between the sections with the soot saw. You'll be in trouble then.

    And check the chimney base for a plugged up thimble.
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