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.

Oil primary control always on

Options
Eldomi
Eldomi Member Posts: 7
Hey folks,
looking for some ideas/opinions. I have an oil burning furnace (not water boiler) with an ST9103A electronic fan timer and a R8991 oil primary control.
i have been having this issue where regardless of the thermostat, the oil burner and fan kick on once power is given and will not shut down.
i verified it wasnt the Tsat issue (replaced it) , disconnected all wires from tstat to timer board (gave it power and it came right on). 
I replaced the timer board and had the same issue. 
Ultimately I undid the orange signal wire from the timer board to the oil primary control cleaned up the connection and wire nut them back together, the same for the oil primary control to oil burner wire. This fixed the issue for 2 days.

now its back to being stuck powered on regardless of thermostat. Once power is give. The unit goes on forever (until it cycles due to high limit). 
What should i test -look for? Do i just go ahead and replace the oil primary control?

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,117
    edited February 2023
    Options
    Did you remove the wires from T T on the R8991 primary? This is the logical next step.

    It is unlikely that the original ST9103 fan timer is bad and the replacement ST9103 is also bad in the same exact way. The wires from the 9 pin Molex plug were used on both ST9103s and the primary control is the only thing that can activate the burner components (Motor, Ignitor etc.). If the T T wires are disconnected and the burner continues to operate, then the Primary control is defective.

    The R8991A is no longer available. You may want to purchase the conversion kit from Beckett

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    EldomiSTEVEusaPAHVACNUT
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Options
    Carlin still makes an equivalent, but I'd ditch it and go with a traditional primary and igniter.

    There was an error rendering this rich post.

    SuperTechEdTheHeaterManHVACNUT
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,117
    Options
    The kit includes a Beckett Genisys Control. (But I am not a fan) along with:
    RW Beckett 5770. Electric box for Beckett burner
    RW Beckett 51771U. Electronic Ignition
    RW Beckett 7006U Flame sensor with mounting bracket

    This is the control I would purchase, there are more diagnostic features:
    Carlin 70200

    You might find the R8991A control on Craig's List or e-bay but the prices are high and there is no guarantee they will last. Also, all the kit parts I listed are available at SuppluHouse.com for less than $200.00

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    EldomiClovis
  • HVACNUT
    HVACNUT Member Posts: 5,865
    Options
    Carlin still makes an equivalent, but I'd ditch it and go with a traditional primary and igniter.
    I've replaced more Carlin Phelon controls with a separate igniter and primary than I can count. 
    EdTheHeaterManSTEVEusaPA
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,117
    edited February 2023
    Options
    HVACNUT said:

    Carlin still makes an equivalent, but I'd ditch it and go with a traditional primary and igniter.

    I've replaced more Carlin Phelon controls with a separate igniter and primary than I can count. 


    Finally something we can agree on. The combination Ignitor, primary control is not the best idea they have come up with. That is almost as bad as the combination Triple Aquastat relay Primary control that Repco oil fired boilers used in the 1980s

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • Eldomi
    Eldomi Member Posts: 7
    edited February 2023
    Options
    An update following the steps from @EdTheHeaterMan . Disconnected the 2 wires from the primary control and turned power on. Blower and burner both turned on.. killed the power and placed the wires back to their terminals, turned power on and heard a slight click, now it wont turn on even with the thermostat calling heat. I flipped power on/off on service switch nothing happens. Note- the click was just 1 time after placing the wires back. And giving power
    Did it die completely?

    Edit:
    if so i am kinda stuck and cant wait for an online order, i see most of the parts listed above are available at big box stores, what controller should i go with that is reliable? (Seems folks like some better than others) 
  • rick in Alaska
    rick in Alaska Member Posts: 1,457
    Options
    If you took the tt wires off the primary and it still came on, you need a new primary.
    Rick
    Eldomi
  • HVACNUT
    HVACNUT Member Posts: 5,865
    Options
    The Honeywell R7284U1004 might be available at your local BBS. But the igniter will be burner specific. If it's a Beckett AF/AFG, they might have it. If your burner is a Beckett AF2, or NX, or a Carlin EZ or CRD, then not so much of a chance. 
    A 1900 box will work for the splices if an OEM junction box isn't available. Get a 1/2" chase nipple to run the wires between the primary and the burner. And likely a new cad cell eye and lead because the existing won't be long enough. 
    It's very important to test the control once it's installed. Safety time and positive shut off at limit. 
    Some pics and info on the furnace and burner will help on setup and testing. You're not messing with anything on the combustion side so I have faith.
    Eldomi
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Options
    You'll need a competent oil burner tech eventually, especially to clean and tune up your system. Why not have one come over and do it. They'll have all the parts on their truck, can check your safeties, test your combustion, and can evaluate your entire system to see if there are any other maintenance issues

    There was an error rendering this rich post.

    SuperTechEldomi
  • Eldomi
    Eldomi Member Posts: 7
    Options
    The unit is an AFG. I ended up going to a supply house near by and got the beckett kit and switch the control for a carlin 42230. The guys there recommended it because i would t be able to take advantage of most modern feature due to not having a solenoid. Attached is a picture on my current set up
    Clovis
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,117
    Options
    By your description, I believe the primary control was malfunctioning in a very dangerous condition. The contacts that connect the Black wire to the Orange wire may have been welded together. If this was the case, the safety function of the flame sensor would have been disabled. This is why a safety check is very important. You check the primary safety control function by removing the flame sensing Cad Cell and make sure the motor stops within the allotted safety time. If the burner fails to shut off as a result of not sensing a flame, then the control is defective and dangerous to operate.

    Once you found the burner operated without the low voltage signal from the T1 T2, I would have recommended that you not operate the burner because there is no SAFETY in the primary SAFETY control.

    The Honeywell R7284 Primary control was mr GO TO control for many years. Then Carlin introduced the 70200 control with a longer warranty and more diagnostic features so I now recommend that control. Beckett just upgraded the Genisys control with more diagnostic lights (I prefer the LCD screen on the carlin and Honeywell) with a C terminal to accommodate smart thermostats. Eventually all the oil primaries will have an App for your smartphone so the digital screen will become obsolete, but we are noy there yet. So either the R7284 or the 70200 are the better choice today in my opinion.

    If you need assistance on the control wiring I will have the updated wiring for you shortly.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,117
    edited February 2023
    Options
    This diagram will preserve the functions of the S9103A motor control by running the (Orange) burner motor wire thru the fan timer. By adding the (Red) L1 wire to the R7284U primary control You will provide the full function of the new Primary Safety Control.

    When Installing the R7284 use the installer set up, (since you have no oil valve) make sure the Valve on delay is set at zero (0) seconds. Otherwise the control will detect an error. Flame detected when there should be no flame.
    Also configure T T terminals ON should say NO so the S9103A can operate the T T terminals.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    MikeAmann
  • Eldomi
    Eldomi Member Posts: 7
    Options
     
    This diagram will preserve the functions of the S9103A motor control by running the (Orange) burner motor wire thru the fan timer. By adding the (Red) L1 wire to the R7284U primary control You will provide the full function of the new Primary Safety Control. When Installing the R7284 use the installer set up, (since you have no oil valve) make sure the Valve on delay is set at zero (0) seconds. Otherwise the control will detect an error. Flame detected when there should be no flame. Also configure T T terminals ON should say NO so the S9103A can operate the T T terminals.
    I ended up getting the carlin 42230 . Any chance you can help with that wiring diagram? Im somewhat confused why i wouldnt continue to use the wires from the molex as they all go into the faulty 8991?
    also in your diagram the red line on the board, that slot doesnt have a spade on the board to actually connect anything to it.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,117
    edited February 2023
    Options
    Here is the 42230 control with the S9103A.

    The Red L1 wire is not needed on the 42230 control since there is no diagnostic memory or LCD screen to keep powered. This is more like the original 8991 control except that the ignition wire must be run to the Ignitor The new Ignitor may come with the spade connectors. If not, then just use the ones that come with the 42230 control. The Cad Cell wires must reach to the new control, I hope the Kit version are long enough. If not, just add some thermostat wire with wire nuts to make them longer.

    Im somewhat confused why i wouldnt continue to use the wires from the molex as they all go into the faulty 8991?

    CORRECT The wires from the Molex plug should all be used. The instructions for the 42230 are different from your wiring as not all uses for the Carlin 42230 are connected to a S9103A. The orange (MOTOR) wire in the Carlin instructions go directly to the motor. If you followed the Carlin directions, you may run into problems with the S9013A fan timer. I remember doing just that and having a problem with the fan timer. It was so long ago I forgot what the problem was, but I remember there was a problem so I always remember to wire the Motor thru the molex plug every time!

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Eldomi
  • Eldomi
    Eldomi Member Posts: 7
    Options
    Here is the 42230 control with the S9103A. The Red L1 wire is not needed on the 42230 control since there is no diagnostic memory or LCD screen to keep powered. This is more like the original 8991 control except that the ignition wire must be run to the Ignitor The new Ignitor may come with the spade connectors. If not, then just use the ones that come with the 42230 control. The Cad Cell wires must reach to the new control, I hope the Kit version are long enough. If not, just add some thermostat wire with wire nuts to make them longer.
    Im somewhat confused why i wouldnt continue to use the wires from the molex as they all go into the faulty 8991?
    CORRECT The wires from the Molex plug should all be used. The instructions for the 42230 are different from your wiring as not all uses for the Carlin 42230 are connected to a S9103A. The orange (MOTOR) wire in the Carlin instructions go directly to the motor. If you followed the Carlin directions, you may run into problems with the S9013A fan timer. I remember doing just that and having a problem with the fan timer. It was so long ago I forgot what the problem was, but I remember there was a problem so I always remember to wire the Motor thru the molex plug every time!
    Awesome thanks. This is how i was thinking it would go. I will work on this tonight after 8p. Report back on success !
  • Eldomi
    Eldomi Member Posts: 7
    Options
    Huge thanks @EdTheHeaterMan and to all that commented to help. Its up and running again!
    MikeAmann
  • HVACNUT
    HVACNUT Member Posts: 5,865
    Options
    Eldomi said:
    Huge thanks @EdTheHeaterMan and to all that commented to help. Its up and running again!
    Did you check the safety time and limit?
  • Eldomi
    Eldomi Member Posts: 7
    Options
    HVACNUT said:
    Eldomi said:
    Huge thanks @EdTheHeaterMan and to all that commented to help. Its up and running again!
    Did you check the safety time and limit?
    I tested the safety by disconnecting a cad cell wire (F-F) watched it shut down /lock out. Replaced wire and reset via red button. 
    I had tested the limit prior to changing those parts and verified the burner and fan shut off once temperature has reached. Any other specific steps you would suggest?
    HVACNUT
  • Clovis
    Clovis Member Posts: 2
    Options
    Newbee here. Same exact issue I am having. Not sure why it took me this long to find this thread, I've been reading here about two week's. On my own I went and fetched a new coil and a 70200. I love the versatility of the 70200, assuming it performs as advertised. Old BDP furnace. Likely change out the pump in order to add a solenoid. My last place had oil fired steam, I loved that system. I got to know it pretty well. Actually had a guy install it, Polish engineer, seriously overqualified, but he knew steam. had left before the fall of USSR, anyway....

    The photos above look just like my unit. Its in a workshop, hasn't been on in the three years I've been here, but it was time. Probably will have to get someone over here to wire it for me. I *did* call a guy when I first went to start it, just though he wanted too much $. I've learned a lot here. For one call someone, lol.

    Anyway, you guys are great.

    I'm going to go have a more careful look at the thread here, and post my question.
  • Clovis
    Clovis Member Posts: 2
    Options
    So anyway, it is the same set up, and I presume the set up of the 70200 would be similar to the 42230. What I do not understand is on my system only 8 of the molex pins are used the center one is empty. Interesting point about the fan timer not working correctly when the motor is powered through the primary.