Used to work just fine and my mid and forward ac/heat systems work just fine. I have very limited electrical knowledge, but enough to know how not to shock myself and use a voltmeter. Where should I start to diagnose this issue? I'm thinking of pulling the panel off and looking behind just to see if wires are rubbing or something to that extent. Or should I start at the unit and work back to the panel? Any suggestions would be great, thank you.
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Aft AC breaker trips
- Thread starter kdumph
- Start date
2texoma
New Member
- Mar 2, 2012
- 113
- Boat Info
- !977 CC200 worn & wounded
- Engines
- 228 Mercruiser parts & pieces
Start with the most likly.
First use amp meter to see if the ac is pulling more amps than the attached tag says it should.
Secound,switch the breaker with another in the box of same amp rating.
Third,furnish more information like;trips instantly,after 3 secounds,intermitntly. Ground fault breaker;yes or no.
Trips on heat,cool,both or only during months with 31 days:smt017.
First use amp meter to see if the ac is pulling more amps than the attached tag says it should.
Secound,switch the breaker with another in the box of same amp rating.
Third,furnish more information like;trips instantly,after 3 secounds,intermitntly. Ground fault breaker;yes or no.
Trips on heat,cool,both or only during months with 31 days:smt017.
Alright taken me a while to get this to project. I have two other AC units on the boat so it hasn't been vital. Looking to sell though and want everything working. It seems to be pulling the correct amps looking at the meter. Maxs out the second I hit the switch and down to 20 or so the same way the other units operate, then it trips. Tried it on a known working breaker(Other AC unit) and no joy.
Trips between 1-3 seconds so there is a slight delay. Also will not trip if I just have the fan running. So I'm guessing compressor now? No idea about the AC units anything else to check?
Trips between 1-3 seconds so there is a slight delay. Also will not trip if I just have the fan running. So I'm guessing compressor now? No idea about the AC units anything else to check?
2texoma
New Member
- Mar 2, 2012
- 113
- Boat Info
- !977 CC200 worn & wounded
- Engines
- 228 Mercruiser parts & pieces
You did well,should get your union card before long.:thumbsup:
As you already figured out,it's normal to pull far more amps on start up than running. I'm thinking run capacitor might be next place to look. There are more than one configuration that can be used to supply capacitance to the compressor so the first task is identifying the capacitor(s). Considering your lack of electrical we will eer to redundant safety while handeling the caps. Momentiarly touch each terminal and chassis with a jumper wire. Then terminal to terminal. One in a while a cap retains a non-lethal charge that can make you need to change your shorts. Shorting will discharge if present. Protect your eyes while shorting because there is one in a million chance of rupuring the cap which is fluid filled. If you incounter an oily substance leaking from a cap,protect your skin until you see the words "NO PCBs",at which point there is no reason for concurn. With oil from a cap and no disclaimer assume the oil contains PCBs and proceed accordingly. Working from compressor terminals back,you will find at least one wire and occasionaly two,leading to a capacitor. There are metal cased normaly grey and plastic cased black caps. The metal grey run cap is what we want right now. If the case looks swollen there is no need to test farther,it's bad. Disconnect wires from cap and needless to say,mark or rember the connections. Set your ohm meter to max and touch each of 2 cap terminals with each meter lead. The reading should go up then fall back similar to the amp meter earlier. If the needle doesn't jump and fall back,reverse meter leads. From here each time the leads are reversed the needle should jump then fall. If not,the cap is bad. This test can 99% positivily tell you a cap is bad but there is a 50-50 chance its bad eventhough it passed the needle bounce test. If you know a friendly hvac part dealer they have a cap tester. It is very possiable the cap is what is known as a dual cap because it has more than 2 terminals and serves both the compressor and fan. If thats the case you are unlikly to find exact replacment so just buy 2 caps and do a little rewireing. Ok,any questions? :smt001
As you already figured out,it's normal to pull far more amps on start up than running. I'm thinking run capacitor might be next place to look. There are more than one configuration that can be used to supply capacitance to the compressor so the first task is identifying the capacitor(s). Considering your lack of electrical we will eer to redundant safety while handeling the caps. Momentiarly touch each terminal and chassis with a jumper wire. Then terminal to terminal. One in a while a cap retains a non-lethal charge that can make you need to change your shorts. Shorting will discharge if present. Protect your eyes while shorting because there is one in a million chance of rupuring the cap which is fluid filled. If you incounter an oily substance leaking from a cap,protect your skin until you see the words "NO PCBs",at which point there is no reason for concurn. With oil from a cap and no disclaimer assume the oil contains PCBs and proceed accordingly. Working from compressor terminals back,you will find at least one wire and occasionaly two,leading to a capacitor. There are metal cased normaly grey and plastic cased black caps. The metal grey run cap is what we want right now. If the case looks swollen there is no need to test farther,it's bad. Disconnect wires from cap and needless to say,mark or rember the connections. Set your ohm meter to max and touch each of 2 cap terminals with each meter lead. The reading should go up then fall back similar to the amp meter earlier. If the needle doesn't jump and fall back,reverse meter leads. From here each time the leads are reversed the needle should jump then fall. If not,the cap is bad. This test can 99% positivily tell you a cap is bad but there is a 50-50 chance its bad eventhough it passed the needle bounce test. If you know a friendly hvac part dealer they have a cap tester. It is very possiable the cap is what is known as a dual cap because it has more than 2 terminals and serves both the compressor and fan. If thats the case you are unlikly to find exact replacment so just buy 2 caps and do a little rewireing. Ok,any questions? :smt001
