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  1. #1
    Join Date
    Aug 2012
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    AC breaker tripping woes

    Sorry for the lengthy post, I've been going trying to get my AC and Hot Water both functioning for over a month now... 6 service calls, still no resolution on the AC issue, still problems with the heat.
    The ongoing behavior is that the breaker for the AC Compressor is continually tripping, with between 15 minutes and 8 hours time between trips.

    I'm hoping to gather enough information for the next HVAC specialist I call, so they don't repeat steps or just tell me to replace the whole unit.

    Equipment I've got:
    Monitor MZ25S tankless hot water heater
    Goodman CK36-1A Compressor

    The hot water heater has been a bit dodgy since I've owned the place (2 years), but aside from the coil in the AC freezing about a year ago (replaced the air filter and it's been fine up until now) it's worked fine.

    These problems started last month, when I came home to a 90+ degree apartment, as well as a loud "clicking" sound from the 3 way valve on the hot water heater.

    quoted sections are the work orders from the companies.
    Call 1 (Company #1):
    No A/C No Hot Water. Tech found that the system had no water in it which made system work against itself so tech filled the system
    Basically, he told me that because there was no water in the system, the three way valve was going haywire and sending hot air through the AC even when it was set to cool.
    Refilling the valve, and turning the hot water heater to "summer mode" (which I think blocks it from sending hot water to the AC?) seemed to work.

    The next day, I noticed cold air had stopped coming out of the system - the condensor unit on the roof wasn't on so air was circulating but it was all room temperature

    Call 2 (Company #2):
    (No/AC) Found breaker to condenser tripped. reset. Found burned contacts on contactor. Replaced contactor & tested operation. Compressor (13.4 of 19.7 RLA) <check> Condenser Fan Motor (.8 of 1.1 RLA).
    System running well inside. 3CAmp breaker range on both legs. Pressures not where they should be (high head pressure & low suction). Cleaned with water,
    pressures did not change, added refrigerant, suction pressure did not come up. Problem most likely in the expansion valve.

    Parts replaced -
    Contactor 30Amp /2 pole / 24V Contactor

    note: at no point did the contractor ever mention he thought it was related to the expansion valve, I just noticed this going through the work orders now.. this was discussed as a side thing to fix but unrelated, and not an urgent fix. Could this be related?

    Call 3 (Company #2):
    (Breaker ripping) found Breaker shorting . Pulled breaker & found multiple breakers that had been burned. Recommended hiring an Electrician to fully go through the panel. Breaker for Boiler also burned + broken and may be causing issues with boiler.

    Call 4 (Electrician)
    had electrician replace breakers, switch position since the bus bar was a bit burned. Damage to the bus bar wasn't bad enough to warrant replacement at this time.

    Call 5: (Company #2)
    (No Hot h20)
    Found Actuator Not Attached to Valve Body. Attached & Tested Operation. Valve Clicking & Should be Replaced. Relief Valve Dripping, unable to check expansion tank (system Pressure @ 7 psi)
    Recommended: Replace 38PSI relief + Expansion Tank, expansion tank must be OEM replacement.
    (No A/C)
    Capacitor reading 40MFD/45 MFD
    Replaced Capacitor & Checked amperage on L1 & L2 - 14.7A / 14.9A. Unable to recreate breaker tripping.

    Call 6 (Company #2)

    (Breaker Tripping)
    Ran A/C & Obeserved Ampergage. Compresser + OFM Drawing 14.5 amps -14.95 amps. Checked resistance across compressor (OK). Checked wire nuts on low (ion?) voltage of contactor. This caused the contactor to release + snap bakc in. Drew 52 Amps on LI & tripped breaker. Checked voltage @ coil of contactor (21 VAC) . Voltage @ Transformer of Allt (21 VAC) . Multitap transformer Using (240V) tap with supply voltage of (208). Change to (208 VAC) tap. Now have (26 VAC) to coil of contactor.

    The breaker then tripped 20 minutes after this call, and is still tripping, between every 15 minutes, up to maybe every 8-10 hours in some rare instances (mostly between 15 minutes an an hour or two though). I talked to the company
    #2 and they said they couldn't help me any more, and offered to refund one of the calls. Couldn't recommend someone else to continue work on it, wouldn't help me further other than saying if I wanted to replace the whole compressor / condensor they could help.

    I'm going to start looking for someone to work on the hot water heater (replace the expansion valve, maybe the ionization probe or whatever the "reset" button is which pops when there's too much heat... I have ongoing problems with this resetting between uses). However, I'm I'm not sure if and how that could be affecting the AC breaker tripping?

    I'm also hesitant to call another HVAC company until I have some more possibilities for them to try regarding this - I've done some googling and most of the suggestions I've seen (capacitor, etc) were already looked into. Also, despite the tech saying he saw it read 52 amps and trip the breaker, it actually tripped 3-4 other times when he was here last and I didn't see him mention anything about the amperage increase.

    Anyway, apologies again for the lengthy amount of info... anything not tried here which I should have an HVAC company try?
    Also, are there any listings on this forum or elsewhere for real HVAC experts, who might specialize in these kind of issues which have stumped other companies? I'm in the New England area.

  2. #2
    Join Date
    Sep 2008
    Western PA
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    Have a look at our contractor locator map.

    I've got an idea or two and, if I am correct, the repair is simple.

    Of course, you've got problems with a breaker panel, so things may not be as simple as I think.

    ONLY a skilled and trained tech on site can figure it out for certain.

  3. #3
    Join Date
    Aug 2003
    Fort Worth, TX
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    I would not let that breaker panel remain in service much longer if there's ANY damage to the bus bar. You may have voltage drops inside that panel you don't know about that are contributing to the breaker trips for the a/c unit. Get a licensed electrician involved ASAP.
    Psychrometrics: the very foundation of HVAC. A comfort troubleshooter's best friend.

  4. #4
    Join Date
    Oct 2006
    So. NH
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    Quote Originally Posted by Shophound View Post
    I would not let that breaker panel remain in service much longer if there's ANY damage to the bus bar. You may have voltage drops inside that panel you don't know about that are contributing to the breaker trips for the a/c unit. Get a licensed electrician involved ASAP.
    I'm also thinking this is an electrical service issue.

    To the OP, I also think your next next call should be to another electrician. Is this an old Federal pacific panel?

  5. #5
    Join Date
    Aug 2012
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    Thread Starter
    thanks, I can definitely get the electrican back, and will consider replacing the bus bar ASAP (hoping that's the only problem and no one has to go ripping out wires running from the compressor on the roof to my circuit box... I've been afraid its something electrical but hvac guy hasnt' been able to further diagnose that since he's not a licensed electrician).

    I think the electrician who replaced my burnt out breaker(s) / moved the position of the most affected breaker said the bus bar shouldn't be a problem the way it is right now right now (looked like it basically just had some discoloration on it from the previous breaker, but when replacing the condensor's breaker he moved it to a different less effected slot.. the breaker taking up its old slot has had no problems since the move and hasn't tripped once).

    I think what he thought happened with the old breaker was that it slowly lost its tightness against the bus bar and thus heat started building up in it. At the time that seemed to really make sense, I'm just not sure why it would still be an issue after moving it to another location, making some electrical issues seem more likely.

    The breaker box is a Murray LC020DC

  6. #6
    Join Date
    Jan 2009
    Saint Joseph, MI
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    IF there's ANY question abotu the integrity of the bus bar and the panel is more than 15 years old, I'd just go ahead and replace it. They aren't that expensive... not compared to the cost oof repalcing most of hte wiring if you have a major arc flash and melt have the box if the bus bar actually comes apart.... or all the costs of having contractors constantly replacing breakers.

    Is this a Homeline or similar low end residential panel? Form the electricians and electrical engineers I've talked ot, that stuff is junk. Put in a commerical/industrial grade Square D QO panel and be done with it. But that's just my opinion. Electricla isn't somethign to mess with and it's something you'd rather not be without.

    It might also be a good opportunity ot upgrade to a 150 or 200 AMP panel if you don't ahve one already. At least upgrade the panel and wiring to the meter and meter base, then replace the incomming feed if needed.

    I'd also have the wiring checked on the AC and boiler circuits.

  7. #7
    Join Date
    Aug 2012
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    Thread Starter
    thanks, as an update as per motoguy128's comment I had an electrician replace the panel (inclduing the busbars) today. It's a similar Murray panel though I think Murray's panels are made by another company now. Either way, on inspection there was no further heat damage to the breakers, and not 20 minutes after the electricians left the condensor's breaker tripped again.
    I've got the electricians coming back tommorow AM to check the wiring on the roof, though they said if it was a problem with a weather damaged wire, it would most likely trip and not reset (this is tripping but letting me reset it after about 5-10 seconds, staying on for 15 minutes up to maybe a few hours at times), so I'm not sure what that will accomplish. IF there's other culprits an HVAC specialist should investigate not mentioned above, I'm all ears.

  8. #8
    Join Date
    Jan 2004
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    Goodman CK,. isn't that a recip, compressor in it.
    Contractor locator map


    How many times must one fix something before it is fixed?

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