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  1. #1

    Long Story, Short Compressor Life! :)

    Good Morning All!

    Been leaching quality info from your great site for a while now and have seen the rules in action. I don't want my post to be misconstrued as a request for DIY advice so, let me pay my Dues.

    I am a Communications Technician by trade and my Brother is a 20 Year Industrial Journeyman Electrician. Neither one of us is a Certified HVAC/R Tech but, between our respective, related fields, we're qualified to do everything short of purchase, refill or, reclaim the various Refrigerants. We will, of course, call upon the services, and compensate accordingly, an HVAC/R Tech to properly handle any refrigerant related tasks or issues.

    "Legal Disclaimer" over... now the fun part....

    My Brother and I have taken some time off to work on our sainted mother's house. Between her advanced age and our busy schedules, well, you wouldn't want your mom living here either...

    Her A/c wasn't coming on at all and I found we only had one 115v leg hitting the unit. Solution? Bus Bar in 40 year old Load Center was burnt. Wasn't a single Two-Pole breaker making decent contact anywhere. So after replacing the entire 200A Service we now had the Fan turning but no action from the Compressor and the Contactor (a 3-pole Definite Purpose Contactor for some reason) was buzzing loudly enough to hear on the other side of the house.

    Opened Control Box and found a Start Capacitor blown all to hell.

    Now, here's where it gets odd. I pulled the Start Cap, Dual Run Cap and Contactor with the intention of running up to my local Parts retailer. While making my usual notes for reassembly, I found the Fan had it's own set of Caps and that both output taps on the Run Cap were wired to the Compressor Run Winding only.

    I know, right?

    Now, I'm thinking this a Dual Run Cap maybe 7.5/40uf and wired parallel the total Capacitance is 47+uf, no biggie. Well, Run Cap was too rusty to read so I had my shop test it...

    It's a 55/10... and in perfect working order to boot.

    Well, I decided to take mom's ole' 3 Ton Copeland back to stock and bought one
    189 - 227uf/370v Start Cap, one 40/440 Run Cap and new DP Contactor. Don't have the Contactor yet... should be in today or tomorrow.

    Put it all back according to the 20 year old schematic on the Control Box cover and... blah...

    The Contactor (yes, the old one) buzzes something awful when the compressor engages. The Compressor itself wobbles a few times, trying to kick over, and with a loud discharge between the Start Cap Taps, the Contactor obligingly disengages after 5 or 6 seconds... only to repeat the process again exactly 10 seconds later.

    At this point, my Brother wants to flip a coin to determine which one of us is going to go tell mom her Compressor is locked up and she's gonna have to wait on that Cruise to Acopulco if she wants cold air when she gets back. I, for one, don't give up that easy...

    Since our mother has had several Techs from several companies out over the years for various issues. I'm assuming it was one of these techs that installed the 55/10uf Dual Run Cap and wired it parallel to the Compressor Run Winding for a total of 65uf. My guess is it was dragging and this was the Techs (obviously) temporary fix.

    I don't know where ya'll are from but, it's freakin' HOT down here on the coast of Alabama from now until October. We did the math and between the money she'll save on the Power Bill pulling all of her window units and a couple of months of Dear Ole' Departed Dad's Pension Checks she can get a nice System that should still be in working order by the time one of us inherits this place. I've got 5 more days of vacation left and I'm ready to try all the 'ole tricks to unlock this box and squeeze 2 - 3 more months out of it. I've got my brother throwing together a switch to reverse/rock the motor and if that doesn't succeed I've got spare Caps for my 5 Ton sitting in my garage.

    So. here's what I wanna spitball off you folks. Proper line Voltage has been confirmed at the unit and the Contactor, no matter how unlikely, has already been paid for and will be ruled out as soon as it comes in. Given the fact, that it's a 20 year old unit and we are already looking at replacement, are there any other possible negative consequences to upping the Run and Start Caps besides "Shortened Compressor Life", that any of you could think of?

    Once again, I'm not looking for advice, just ya'll's experienced opinion. We're not gonna disappoint our Momma without trying everything but, as I sit here drinking my morning Redbull it dawned on me. It wouldn't hurt to run our plans and intentions by a few Pro's just in case there are some hidden pitfalls we're not aware of.

    Sorry for the long post. We're on a fairly short schedule and won't have time for the usual follow-up question/answer sessions so I wanted to get all the historical, technical and situational details out there from the start.

    Also, If any Moderators feel there is a better Topic for this question and need to move it, leave a few crumbs so I can find it.

    Thanx for your time, Ya'll!

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,062
    You did not mention the start relay?

  3. #3
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,376
    If power supply to the unit has been iffy for some time, I would not put much faith in the existing contactor, and if you're talking about a true start capacitor with a potential relay, nor would I put much stock in the relay if it has not been replaced alongside the start cap.

    As for the unit itself, pushing twenty years old, maybe you and bro could chip in a few bucks to help get her some new stuff on the ground outside. And then she could still make Acapulco.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  4. #4
    Whelp... You both jumped on something that I didn't even think about... Since the Compressor was trying to start the whole time, I just assumed the Start Relay was good. I had automatically decided (since both Caps and the Contactor are a whole measly $$ bucks) to change everything in the Control Box and didn't even price the relay... (DUH!) I'll pick that up when I go back for the Contactor. It can't be more than a few bucks and like the Contactor, is worth swapping out just to say we did.

    Come to think of it, I mentioned above that there is a pretty substantial arc between the Tabs of the Start Cap when the Contactor disengages. I've never seen that happen on any of the other Units I've worked on but, there is some unused potential somewhere... either still in the Start Cap itself or back fed from one of the other components.

    As for new "Outside" gear.. That is our plan "B". Since I've already changed out all the Controls... we could just buy a compressor and call it square. The Condenser BTW, is one of those 4' tall Carrier 38ES Series "Towers", as people seem to like to call them and, along with the fan is still in pretty good shape. I priced one with a nice warranty for $$ bucks so, we figure prolly $$ bucks for the whole shebang after we pay one of your fellow Techs to Test and Charge it.

    We're proceeding with "Plan A" in the mean time, We're all prepared to Double Down on a complete refit and, would prefer it. A new HE unit would be advantageous weather we sell this place one day or, maybe move back home after Mom's moved on and, in the mean time, she gets "worry free" Climate Control...

    On that note... do either of you, or anyone else for that matter, have an educated opinion on my original question? If the Contactor and Relay ain't the problem, (and I'm pretty sure it ain't) then the Compressor's days are numbered and burning it up with Parallel Start and/or Run Caps won't break my heart. Just wanted to bounce my plan off a few of the Pro's around here in case there was something I was missing...

    Thanx Again!


    Pricing isn't allowed
    Last edited by jpsmith1cm; 04-24-2013 at 09:03 PM.

  5. #5
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,376
    A start capacitor cannot remain in the circuit for more than a split second, or it will burn up. If the compressor is reluctant to start even when all of its starting components are working properly, the compressor is done.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  6. #6
    Join Date
    Mar 2013
    Location
    Joplin,Missouri
    Posts
    310
    Any time you come across a burnt start capacitor ALWAYS replace the start relay

  7. #7
    Join Date
    Aug 2012
    Posts
    2,755
    I'm not buying any of this smooth talk. Stop trying to save your inheritance and invest in at least a new condenser. Lets see your already 3 or 4 hun in the hole minus brain power.
    My name is TooCoolforschool and I am a chronic over charger.

  8. #8
    Yeah... Like I said earlier... I can't believe I totally spaced on the Relay...

  9. #9
    ??"3 or 4 hun in the hole minus brain power"??

    2 Caps, 1 Contactor, 1 Relay, and a 12 pack for the "project staff" and I've still got change left from the Benjamin I left the house with...

    Luckily... I have "brain power" to spare...

  10. #10
    Join Date
    Aug 2012
    Posts
    2,755
    Quote Originally Posted by Roam8 View Post
    ??"3 or 4 hun in the hole minus brain power"??

    2 Caps, 1 Contactor, 1 Relay, and a 12 pack for the "project staff" and I've still got change left from the Benjamin I left the house with...

    Luckily... I have "brain power" to spare...
    I was being generous, but you are still wasting your money.
    My name is TooCoolforschool and I am a chronic over charger.

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