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Honeywell R7284U oil primary

sparkiesparkie Member Posts: 46
Just to verify wiring  for the "limit" and "L 1 " terminals---  simple furnace hookup.

Line from high limit goes to both?  Or is it nescessary to run another hot line directly to L1?


  • billtwocasebilltwocase Member Posts: 2,385
    do you

    need a post purge on this?  Is this a warm air or boiler?
  • sparkiesparkie Member Posts: 46
    Warm air furnace

    No post purge at this time, but in the future im going to install a clean cut pump, then i will set it up with pre and post purge. Wiring diagram is a bit vague on L1 and limit connections. The way i see it, i can feed both L1 and limit with the line from the hight limit on furnace. This only time this line would open is if the unit shut down on high temp safety, thus killing all power to burner and control as is the case with the 8184. 

     But does this unit need a seperate hot line that does not go through any limit,in order to run the control itself?  Also would a post purge be beneficial even if it doesnt get a pre purge?    As always, thank you Bill
  • freddrow2002freddrow2002 Member Posts: 18
    edited February 2012

    yes you call tie them together and it will work correctly. even if you add a clean cut pump it should still work just fine. you just lose any history stored in the controland of course you lose the ability to use post purge by not having an L1 hooked up.
  • STEVEusaPASTEVEusaPA Member Posts: 4,419
    I would wire it as noted,

    Separate power on L1, before the limit, thru all the conventional disconnects. Power thru the limit, otherwise, the control would shut off on limit and not allow any post purge, or rewire when you add the delay valve and post purge.
  • freddrow2002freddrow2002 Member Posts: 18

    of course you lose post purge as well
  • billtwocasebilltwocase Member Posts: 2,385
    you will need

    to combine the L-1, and Limit to make it work as the others stated. Pre and Post purge make for a clean and happy unit. Unless the furnace goes off on high limit, you always have power to the control. As you know, "T-T" is what runs the show, where as B-1 would power Limit out of an aquastat. Do you have a clean cut pump, or solenoid?
  • sparkiesparkie Member Posts: 46
    Clean cut

    pump was purchased today. I am going to install this sooner rather than later.Having issues with after fire and oil dripping and and carboning up the nozzle and electrodes. I am going to update the system with new pump, control, pre-post purge and a new garber spin on filter.

     One question about the pump---The cordset that came with it has a 4 second delay timer built into it (beckett part # 21887) If i set the primary for a 10 second valve on delay, once the control sends power to the pump solenoid, there is another 4 seconds delay. I dont see any problem with this, as it will still ignite well within the 15 second lockout time.   I questioned this at the supply house and they said it was the only cleancut pump they stocked.
  • freddrow2002freddrow2002 Member Posts: 18
    you'll be fine

    you'll lite with 11 seconds left in trail for ignition. plenty of time left. you can set the pre purge for whatever you need once the control sends power to the clean cut that when the 7284 will start the 15 second count down for lock out.
  • billtwocasebilltwocase Member Posts: 2,385
    I thought

    both plugs came with the Beckett clean-cut pump. One the PD timer, and the other was a standard plug? You should be Ok, but it will be at least 20 seconds before light off. If it was me, I would find the basic plug
  • sparkiesparkie Member Posts: 46
    I thought

    both plugs  came with it also. But as Fred mentioned, if my valve on delay is 10 seconds, it will be a total of 14 second delay with 11 seconds to go in the trial.

    Im wondering if maybe it wasnt packed in box at factory or someone in supply house opened it and misplaced it. Just for the heck of it i think ill inquire a little.
  • sparkiesparkie Member Posts: 46
    I thought

    both plugs  came with it also. But as Fred mentioned, if my valve on delay is 10 seconds, it will be a total of 14 second delay with 11 seconds to go in the trial.

    Im wondering if maybe it wasnt packed in box at factory or someone in supply house opened it and misplaced it. Just for the heck of it i think ill inquire a little.
  • billtwocasebilltwocase Member Posts: 2,385
    The Suntec

    version came with the standard plug only, but I recall the Beckett version came with both. Someone needed one evidently. 
  • MictrikMictrik Member Posts: 1
    I am new to this forum and this is my first post. I just installed a R7284U 3 hours ago, replacing a failed older electro mechanical R8184G. After looking at the schematic and the wires on the Becket AFG I wired it as follows:

    L1 (Black) - to hot from aquastat (high limit)
    Limit (Red) - to hot from aquastat (high limit)
    L2 (White, using one of 4 connections) - to Neutral from aquastat
    Valve (Violet) Not connected because I do not have a solenoid valve at this time.
    Ignition (blue) - to hot line from AFG's igniter
    Motor (orange) - to hot wire from AFG's Motor
    Cad wires (Two Yellow) - to both CAD wires as before.
    Neutrals from Igniter, Motor, R7284U all wired to neutral L2 from aquastat.

    **Igniter and Motor were previously wired together with R8184G, I split it out.
    ***Jumpers were across both T's on R8184G, I did the same on the R7284U but after reading the manual it seems the R7284U can be configured to do this internally via the setup so this may be unnecessary. Is this true?


    I believe it is best to have a separate constant hot wired to L1 so that the unit is always powered and not just during a "call for heat" from the aquastat.
    Wondering if it matters which method i use for adding constant power to L1??

    Method 1:
    Replace the 14/2 wire with a 14/3 (two hots, neutral & grd) and using one hot for the aquastat Limit Red and the other for the constant power (black) then wire all the neutrals together.

    Method 2:
    Add an additional 14/2 and wire to L1 (black) while combining neutral with other neutrals.

    * R7284U control has facility for four separate common connections, not sure why (perhaps wire nuts to crowded?) but unless there is a reason not to I would rather combine all neutrals due to limited box space.
    *Grnd (green) from new wire will be wired to box which is at present missing.

    Can anyone tell me where I may be wrong here and/or add some insight? As presently wired with its its sole source of power coming from the aqustat limit the controller can only be configured during a call for heat. This is not optimal.

    Any info on this from someone who really knows this unit would be very helpful myself and others.

  • billtwocasebilltwocase Member Posts: 2,385
    edited October 2014
    I bought a couple of these when they first came out a good 3 years ago? I have not installed them yet, as I have been using the Genisys solely. If you need a post purge function, you will be powering L-1 constantly. Limit is from your aquastat B-1. If you don't use a post purge, both L-1, and limit need power. They can be combined. No need to run the extra wire if you are not using post purge. I also combine all the neutrals, although I recall they prefer individual neutrals. The blue wire would be power for the ignitor, orange is motor, purple would be fuel solenoid, red is the limit, black is L-1, white all neutals. I think I remember the programming for the T-T internally, but I also would jump it externally. Does this help? I did like the display feature, but prefer the contractor tool method of programming. Keeps the homeowner's hand out of the soup
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