Air conditioner breaker tripping Intermitently

[Sail365]

Hello,
For years now, when i first turned on the ac it would trip within minutes, but the second time would run indefinitely (days and days). Recently, the unit now trips randomly, sometimes after 12 hours, sometimes after 1. I have no idea why. I've replaced the breaker and cleaned the trap. I plan to replace the pump (as its sort of acting the way it did when. I used to be in a place where id suck up jellyfish), but not sure where to go from there.

Any thoughts?

Thanks!

[paulajayne]

DO the calcs. - Get the rating of the air con unit and compare it with the breaker size.

My guess is breaker is very close to limits.

Initial start-up has an inrush and will draw higher that its rated amperage. Hence the trips on start.

Uprate the breaker but be aware of the cable size feeding it and ensure that it can handle it.


One of my compressor motors is rated at 235 amp and I can see in excess of 450 amps on start. (Industrial refrigeration).

Paula

[Lepke]

Bad connections and heat can cause tripping. Too much tripping will ruin the breaker. I use a heat gun to check my connections yearly. Rarely, but I find some breaker screw or another connector has vibrated loose. Doesn't happen in a house. No engine I guess.

[Outlaw7]

First thing I would check is low water flow, Most people clean the strainer basket but seldom check the head. Also if you have not cleaned the condenser in a while try that. Sounds to me like high pressure is tripping the HP switch and then the unit is trying to start against head pressure.

[svHyLyte]

If the breaker is tripping when the compressor is trying to start, odds are you have a Weak or failing capacitor in the control module. Check it yourself if you know how or have it checked before you cook your wiring to the thing. BTDT...

[Sail365]

Thank you for all the replies! Allow me to clarify, the unit is tripping after several hours, seemingly randomly.

[Outlaw7]

You will need a set of gauges and a vigilant eye. It would help to have an ammeter with a hi lo function. Set up the gauges and monitor the high side to see if the pressure does not creep up over time. If you are lucky and by the gauges when it trips you may see a problem with the high side pressures being to high. Again generally caused by a lack of water flow. Second if the high side is rising the amps it is pulling will go up and with a meter with a hi lo function it will capture what the amps where when it tripped the breaker. If the high pressure was within the range for the freon in the system then I would suspect a bad connection somewhere. Also I have had some thing similar to happen when the wires on top of the compressor had a bad connection, this would cause a heat build up and the overtemp sensor on top of the compressor would trip, however it generally does not trip the breaker until it cools, however if the pressures had not equalized the subsequent compressor startup could pull too high of a load for the breaker.

[Kita]

Originally Posted by Outlaw7

You will need a set of gauges and a vigilant eye. It would help to have an ammeter with a hi lo function. Set up the gauges and monitor the high side to see if the pressure does not creep up over time. If you are lucky and by the gauges when it trips you may see a problem with the high side pressures being to high. Again generally caused by a lack of water flow. Second if the high side is rising the amps it is pulling will go up and with a meter with a hi lo function it will capture what the amps where when it tripped the breaker. If the high pressure was within the range for the freon in the system then I would suspect a bad connection somewhere. Also I have had some thing similar to happen when the wires on top of the compressor had a bad connection, this would cause a heat build up and the overtemp sensor on top of the compressor would trip, however it generally does not trip the breaker until it cools, however if the pressures had not equalized the subsequent compressor startup could pull too high of a load for the breaker.

Spot on! I have one that trips random also,but I found that when it gets cabin cool the compressor shuts down then will try to restart really before the head pressure comes down enough, so hard start,trip breaker...I found that a fan helping to move the cool air away from the unit keeps the compressor from shutting down & it runs forever like that..of course it also is saying the unit is undersized for the area.. plan is to upgrade soon,but for now the fan helps to keep it from shutting down especially at night

[Squanderbucks]

How many AMPS does this unit pull when starting up, and what does it run afterwards? How many AMPs is the Breaker rated for?

If it is on a circuit with other appliances - it may be that the load is close to the limit and when someone either turns on another device or another compressor starts up like the fridge or a battery charger then the overload occurs. I installed a SoftStart capacitor unit on my A/C and it greatly reduces startup draw.

If you don't have a 110 AMP meter I would suggest one be installed - mine is a Blue Seas unit and I have trained everyone on board to look at the ammeter before turning on a new appliance or device.

Most lay people don't understand that electricity on a boat is not "unlimited" like at home. Same with water supply.

[Ndavies]

I just solved a somewhat similar problem, and it turned out to be a 2-part solution. My AC was randomly tripping after both units ran for several minutes. I noticed a gradual rise in the current on my ammeter before it tripped. When I ran the forward unit alone, it would not trip, but eventually came up with a high pressure error as the current/load increased. First thing I did was to clean the strainer - I do this regularly, so that didn't change things. Next I flushed both coils - first with a garden hose and then with barnacle buster. This moved some crap out!

I was still getting an issue when I ran the units on shore power - load increasing and voltage dropping - but this did not happen when I ran the units on the onboard generator. The problem was finally solved when I changed out the receptacles (boat side) on the shore power connectors. These showed some signs of burning and when I checked the connections there was some corrosion. So I trimmed back the cable and replaced the inner part of the receptacles.


Problem seems to be solved - both units run great on shore or ship power. My theory is that the partially blocked heat exchanger coils were putting the compressor under increased load - this resulted in the high pressure alarm and may have been the straw that fried the receptacles. Or perhaps they were just due to be changed. Hope this helps!
Neil

[thunderhoof]

Circuit breakers get tired and fail. You may need to replace it. Some types of beakers are more susceptible to tripping near, but not over, their limits. Get some advice as to whether a one size larger breaker is safe to use. Most equipment failures cause a jump in current, not a small increase so one size up might reduce nuisance trips.
That said, if the breaker is replaced size for size and the trips continue, then you have an equipment issue.