Old contactor different than new contactor wiring help

Discussion in 'HVAC Heating & Cooling' started by Mikemikemike, Apr 10, 2021.

  1. Mikemikemike

    Mikemikemike New Member

    Joined:
    Apr 9, 2021
    Location:
    Virginia
    Hi all,
    I did a search for this and found some similar posts but not quite what i was looking for. Im replacing my old carrier single pole contactor with one of the newer models, Im not sure about the wiring and was hoping you guys might be able to help. I have 2 main questions.
    1. In its current state(if I'm looking at it correctly) on the old contactor the line side is on the left and set of contacts is to the top with the shunt at the bottom, on the NEW contactor if oriented with the stamped L1/L2 to the left side, the set of contacts will be on the bottom. does it matter if I rotate the new contactor and keep the contacts at the top so that the power lines go into the T1/T2 side and come out on the L1/L2 side or should I keep the l1/l2 on the left and move the line wires to match the new setup (contactor at bottom shunt at top)

    2 second question where do I put the (2)red, (1)brown and (2)yellow wires that are sticking out the front the 2 red wires go down to the compressor, the brown wire and the inside(closer to the middle) yellow wire go to the control board below the contactor and the other yellow goes to the high pressure switch (i think) its a switch attached to a copper tubing at the bottom of the unit just not sure where to plug these guys into the contactor.
    any help would be appreciated thank you
    photos attached new contactor.jpg old contactor.jpg wiring.jpg
     
  2. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    Should use only use a double pole relay. Single pole relays leave one side always hot. It doesn't matter which way you mount it, the coil is 24v ac and mount it however is needed. Do put the line side on L1 & L2 for safety. There is no electrical difference on either side of the contractor.
    The new contactor should have enough spade connectors for all the wires. If the top picture is of the replacement, it's a single contact and it's hard to see the coil connectors. They are two spade lugs on the bottom of the relay and on the top side. each side is one end of the coil.

    https://www.homedepot.com/p/Connect...te-Purpose-Contactor-BEBDP2P30A240V/310122186. Notice all the lug connectors on this universal DPST contactor. Coil connections are on the each side. This is a fairly common contactor used anywhere, even for 220v irrigation pumps.

    [​IMG]


    I found this doing a search. Notice the multiple wire connectors under the screws. The coil connections are on the side. Do not follow these color wires, use the diagram from your unit. However, the L1 % L2 will be BLK-BLK or BLK-RED. Here is is BLK-RED
    [​IMG]
     
    Last edited: Apr 10, 2021
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  4. Mikemikemike

    Mikemikemike New Member

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    Apr 9, 2021
    Location:
    Virginia
    Worth,
    thank you for your reply
    Great point about the l1/l2 staying on the line side for safety i didnt even think about that.
    I have plenty of spade connections 4 on each side of each of the legs and 4 total on the coil (2 top and 2 bottom) I guess my real question is which of the wires sticking out of the front (2red,1brn,2yel) go to the coil and which can be put on to one of the legs and of the ones I put on one of the legs do I put it on the line side or the load side? sorry if you already explained this and i am not understanding
    thanks again
     
  5. WorthFlorida

    WorthFlorida The wife is still training me.

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    Retired
    Location:
    Orlando, Florida
    Why are you changing this out? It looks good. Is it not starting or the fan running slow?

    Since this is a single contactor for 240v I'm guessing this is over 20 years old. It is common for techs to add a hard start kit so that is what the red wires are for. Not 100% what they are for but they are on each side of the contactor. To get L1 L2 correct is just for labeling. Most techs are good and they know which side is which but a future homeowner may not know. Besides, a cutout switch should be mounted near the unit to remove power when servicing. 21 and 23 reference the terminal numbers from the wiring diagram. L2 and 23 is the shunt. You probably know this but I write these should others read this post and learn from it.



    old contactor.jpg
     
  6. Mikemikemike

    Mikemikemike New Member

    Joined:
    Apr 9, 2021
    Location:
    Virginia
    Im changing it out because the contactor is starting to make a buzzing/humming noise, im assuming the contacts are pitted/crud in there. everything still works but I dont want to push the issue. yes it is over 20 yrs old just trying to give it the best chance to keep going for a few more years. thank you for labelling the pic this helps a lot I really appreciate it!!
     
  7. WorthFlorida

    WorthFlorida The wife is still training me.

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    Location:
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    A buzz noise is a bad contactor.
     
  8. fitter30

    fitter30 Well-Known Member

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    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    Red wires are probably crankcase heater not a hard start kit. With contact open heater runs through compressor windings to pick up L2 when contact closes both sides of the heater are on L1 turns heater off. Thats why the manufacturer uses a one pole contactor.
     
  9. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
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    Retired
    Location:
    Orlando, Florida
    Good point. A heater would be for a heat pump unit.
     
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