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Ask Robert Your Own Question
Robert, RV Mechanic
Category: RV
Satisfied Customers: 13005
Experience:  18 yrs. RV experience including Cummins North West, Country Coach, Monaco Coach - vendor certified.
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I have a duo therm RV air conditioner model 57915.522 and I'm

Customer Question

I have a duo therm RV air conditioner model 57915.522 and I'm looking for all the capacitors and if you have to get on top to change.. My son changed the shore power plug and reversed the polarity. AC and inverter trip my shore power GFI even with everything isolated. The capacitors are the first thing I thought of for the AC unit. I at least need to get this fixed first. Can you advise. THX
JA: Many things can cause trouble with the A/C. Some simple, some complicated. Fortunately, the mechanic I'm going to connect you with knows all the tricks and shortcuts. Are you hoping to fix this yourself?
Customer: yes
JA: Great! What have you tried so far?
Customer: I can test the capacitors, I'm not sure if the circuit board could be fried.
JA: Is there anything else the RV Mechanic should be aware of about your RV?
Customer: Well just for the AC I have isolated everything except that breaker and it trips..It's the same with the inverter isolated.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the RV Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: RV
Expert:  Robert replied 1 year ago.
Hi my name is***** you have to go top side and remove the shroud and they should be visible, some are inside a metal box and the metal box will have one screw you have to remove to expose them. I would bring a can of wasp spray as sometimes this time of year wasps and bees like to make nests under the cover so be ready for that. Also what you need to know is you can not touch across the posts on the capacitor, you can get a severe jolt as they store energy, I am going to give you a service manual which should help you out on troubleshooting and you can see how to discharge the capacitor, many times when they fail they will burn the wires on the top of the capacitor... Click HERE for a service manual, see page 29... Hope this helps some, please feel free to contact me if you have more questions or concerns Robert
Customer: replied 1 year ago.
OK, I located the capacitors, but did not check them. The smaller black one had some kind of plug that said motor start on top of the { plastic/ bakalight } capacitor. My main concern is the GFI trips when I try to energize the AC when everything in the RV panel is isolated. Not to mention the inverter circuit as well. Is there a circuit board that I need to check first? I have the inside shroud off now exposing the control knobs. Remember the shore power [ hot & neutral ] were reversed at the plug and plugged in several times before that problem was found. Then all these problems came up. A couple of days ago when troubleshooting and isolating the AC fan did come on, but tripped when switched to cool mode. Trying to at least get this resolved by the weekend. THX JIM
Expert:  Robert replied 1 year ago.
OK Which GFI is tripping on the supply post? Are you using any adapters or extension cords on the main cord? Robert
Customer: replied 1 year ago.
Yes, the main original cord #10 that the plug was replaced on and a adaptor from a 3 prong [ dryer style ] to the standard receptacle. The main cord outer jacket was melted some about 6 feet from the plug after it was swung over a pressure washer muffler. We cut about a foot more of the cord and my son replaced the plug and switched the hot and neutral. This is when all the problems started. Just so you know the melted outer jacket didn't effect the RV since it was in use for some time. Only when polarity was reversed. JIM
Expert:  Robert replied 1 year ago.
OK So I think what I would do is get a polarity checker and plug it into all the outlets to make sure you still do not have a wiring issue, the polarity checker will pick up on that. I would also plug in direct with NO cords or adapters, the adapters and cords can cause issues, you can have line loss where you go to turn on a high amp appliance and it would trip the breaker. Really difficult to say for sure the issue without testing the items out, it could be the circuit board capacitors if it is blowing as soon as you turn the AC unit on, normally on a bad compressor it would kick on and then trip the breaker for the AC unit. IF it is on the supply post it sounds like the incoming AC power could be at fault. The service manual should help out some. You can not run the AC unit off a standard household outlet, it will not work, you need at least a 30 amp service. I just want to make sure the supply is not the problem, not a fan of throwing parts at things. IF you would like to get another experts opinion on this please let me know, I only get credit when you select a rating... Robert
Customer: replied 1 year ago.
This is tripping the GFI breaker [ 20amp] from shore power and yes I relocated the camper closer to the house at my sub panel with #2 supplying . Voltage is good at both locations. I have used the AC in the trailer at both locations before with no problems. I used the simple yellow plug in receptacle tester for correct wiring/ polarity troubleshooting. All says good. Nothing was done other than the main cord plug. I checked the polarity at the sub panel at which the trailer has been used before. Can this reverse polarity issue short everything out?
Expert:  Robert replied 1 year ago.
Sure it could and I suspect the board may have been damaged, the board uses DC and AC voltage. What I might do is disconnect the main AC wires at the AC unit and see if it still trips if so then it is an issue with the AC unit. But would be hard for me to say 100% which component failed, it could be the circuit board on the AC unit or one of the capacitors. I would think if it blows as soon as you turn the AC unit on it is the board... Robert
Customer: replied 1 year ago.
That was what I thought I may do next to make for sure the wire is good going to the AC. Do you think the board is in the housing with the control knobs? [ 2000 duo therm rooftop AC only ]. I will try that next tomorrow. But my inverter has the same issue not to mention the hot water heater.
Customer: replied 1 year ago.
Do I need to rate you before I switch questions regarding the inverter?
Customer: replied 1 year ago.
I will run a new cable and see what happens when the AC is energized with a new cable. THX
Expert:  Robert replied 1 year ago.
we normally get rated per question but I can still try and help you here. Do you have an inverter OR power converter? An inverter allows you to have AC power when you are unplugged a power converter will not do that. A power converter takes the AC voltage and makes the DC voltage and charges the battery. The inverter would also charge the battery.Can you get me the make and model of the inverter or converter?RobertAlso what is the Year, Make and Model of the RV?
Customer: replied 1 year ago.
I have a 2000 thor trailer with a model # ***** power inverter series 6300a. AC is just a rooftop with no heat pump. JIM
Expert:  Robert replied 1 year ago.
OK That is a power converter it will take the AC voltage and make DC voltage, and charge the battery, what is the going on with that? It might be a few mins before I respond back going to get a bite to eat..... Robert
Customer: replied 1 year ago.
I can use the breaker in the trailer battery and the 12 volt lights work fine. Shore power to the / AC and general / HW heater trip the GFI breaker.
Customer: replied 1 year ago.
I'm going in for the evening
Expert:  Robert replied 1 year ago.
OK I am trying to figure everything you have going on. The power converter will make the DC voltage when you are plugged in. The DC voltage items are the lights, water pump, fridge, furnace etc. The water heater would have an AC heating element if you have a breaker for it. IF the breaker is tripping then the element could be burnt out. IF it is tripping the GFI on two seperate breakers I would verify the incoming power source.
Customer: replied 1 year ago.
OK I'll get back with you after I try a need main cord. If you think of anything else e-mail me. Will I still be able to talk with you or will I get somebody else. JIM
Expert:  Robert replied 1 year ago.
Just respond here if needed.... Robert
Expert:  Robert replied 1 year ago.
Was just checking in to see if my answer helped??? IF you have more questions or concerns please feel free to contact me... Robert