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Voltage Problem?

Here's a cooked contactor. One wire going from the contactor to the capicatator was burnt through, everything else was tight.

Any opinions?

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  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380

    Hey Jeff,

    It looks like someone tried to solder the connection with a "B tank".

    For situations like this, I always recommend that my students carry a stick and a bag of marshmallows on their trucks.

    Thanks, buddy
  • jeff_25
    jeff_25 Member Posts: 110

    jeff, loose wires and a hard working unit is the condensor clean jeff
  • Empire_2
    Empire_2 Member Posts: 2,343
    Bottom Line

    Replace the contactor and use a clamp on amp probe!!! see what is happening. Excessive current draw can cause this, but you need to provide more history, and what you think happened to this contactor. Do you have an amp probe??? What is the FLA and The LRA rating on the unit for starters. Also if the contactor coil voltage is 24vac, why is the wire so cooked??? Just give us your thoughts please. Have you been there before, is this a reoccuring problem, first time you saw this. No offense but we need a-little more info that a picture saying look at it,.What's wrong. No dissrespect intended.
    Mike T
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Do You Still Have the Contactor

    Jeff, do you still have the contactor on hand?

    The reason I ask is that is looks as though the smaller red wire may have been damaged when the solderless connector was installed. When the insulation was removed, it is possible that some of the strands were also re,pved from the wire, reducing the diameter and current-carrying ability of the wire.

    If you have it handy, please check it for me.
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Do You Still Have the Contactor

    Jeff, if you still have the contactor, check the smaller red wire and see if some of the strands of wire were damaged when the wire was originally stripped. It looks like the solderless connector on that connection is loose, especially given the color difference between the terminal and the solderless connector.

    The burn mark on the the larger red wire seems to be the result of having come in contact with the solderless connector on the smaller red wire.
  • don_144
    don_144 Member Posts: 27

    like a loose wire got the best of it.I would say the contactor was replace before and if you look real close at
    the flat piece under screw its cock.

    That flat piece is made to hold the wire down tight and also made to hold down the clips that support all the other wires on the load side.

    I see this problem alot on disconnects and breakers.

    Always check wiring tightness.very important often overlooked.
  • Jeff Lawrence_24
    Jeff Lawrence_24 Member Posts: 593

    All the wires on the contactor are tight and the condenser coil is clean.

    Read on...

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  • Jeff Lawrence_24
    Jeff Lawrence_24 Member Posts: 593
    As I sit here

    I don't remember what the RLA and FLA amps are on the unit, but they were well with in specs. The 24v wire is charred like that because the wire was so close to the other wires that were burnt. The contactor in the picture was a 'standard' 30 amp rated contactor with a 24v coil. It's a 'Cumberland' unit manufactured by Trane as an off brand.

    There is an interesting story behind this unit. I was referred to the homeowner through a freind. He got the entire system (furnace, evap coil and condenser) used from a church member and wanted to do all the work his self. The owner had been laid off and didn't have a lot of money. He called me to do the venting, gas line, and refrigerant connections. The former owner of the system told the current owner about the contactor needing replacement often.

    BTW Mike, no disrepect would have been taken. Now you know about all I know.

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  • Empire_2
    Empire_2 Member Posts: 2,343
    I agree

    It does look like a loose connection which in turn will cause a heat build up and eventually charred connection till she finally blows...
  • Bob Eh?_2
    Bob Eh?_2 Member Posts: 42

    Looking at the overall contactor assembly it also looks like there is a significant amount of corrosion occuring (look at the areas that aren't cremated).

    Look at the contact assemblies and see whay they look like.... I would make sure that the replacement has better weather protection. Remember that for a significant part of the year the contact does not get operated and this would give lots of opportunity for corrosion to do it's work.

  • Rodney Summers
    Rodney Summers Member Posts: 748
    looks like rust damage becomes heater element -

    by the looks of it, if that orange stuff on the metal contact is rust - and that rust does appear to be under the contact / connector tab - then my guess is that this unit's electrical area sat out in the "wetness" (maybe at the church) for some time before the final owner received it. the contactor conn/tabs had slightly rusted, but somebody went ahead & connected them anyway. once the rust gets started underneath, then the yearly outside environment will push the rust further to eventually destroy the connector & increase the resistance. rusted contactor connector tab @ 230v/10a basically = heater element & you've seen the result. if it were an over-current situation, then the breaker should have blown to prevent it. so, 2 things to check. make sure that the breaker (both sides) is good (trips properly @ rated current)before hooking that thing back up and if that compressor is rated at anything greater than 3 tons, then i'd replace that contactor with at least a 40fla over a 30fla for good measure - they basically cost the same so if it fits, put in the bigger one.

    safety first.
  • Jeff Lawrence_24
    Jeff Lawrence_24 Member Posts: 593

    To the best of my knowledge, the condenser went directly from the givers house to the recievers house and never set uncovered outside in the rain.

    The best part of it is the circuit breaker on the condenser never tripped....

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