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Dometic Rooftop AC throwing breaker


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We just brought a new to us 2015 coachmen clipper home today. We plugged in to a 12 gauge 100" 110V extension and turned on the AC. It ran fine then I turned it to high and seconds later it went off, it had thrown the breaker in the house. Then we got a 30 amp extension cord and plugged it in and it ran for probably 2 hours before it did the same thing, threw the breaker in the house and the outlet was hot to the touch. Any ideas on wha the problem might be? Thanks.

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On 07/22/2017 at 6:50 AM, GlennWest said:

Well it was and I do apologise but if he has pics of a hitch on a new Smart it needs to be shared. Maybe a new topic

 

Glenn,

His came out thru the bumper cover, I did mine a little different by having the receiver come out just under the muffler. Ours is a bolt in and I do have pics but need to retrieve them as they are currently being held hostage by Photobucket. You are more than welcome to take a look at it in Hutch.

2017 Kenworth T680
2015 DRV 38RSSA Elite Suites
2016 Smart Prime

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2 hours ago, WheatBread said:

We just brought a new to us 2015 coachmen clipper home today. We plugged in to a 12 gauge 100" 110V extension and turned on the AC. It ran fine then I turned it to high and seconds later it went off, it had thrown the breaker in the house. Then we got a 30 amp extension cord and plugged it in and it ran for probably 2 hours before it did the same thing, threw the breaker in the house and the outlet was hot to the touch. Any ideas on wha the problem might be? Thanks.

Those 110V adapters are just good for 15 amps. Where ever the heat is, it is the location of a voltage drop, If you have it in a 110v standard outlet, it's likely just a 15 amp outlet. voltage drop causes the ac to kick breakers. 

The lower the voltage is at the unit, the higher the amps goes the breaker sees .

 

Edited by Charlied
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3 hours ago, WheatBread said:

We just brought a new to us 2015 coachmen clipper home today. We plugged in to a 12 gauge 100" 110V extension and turned on the AC. It ran fine then I turned it to high and seconds later it went off, it had thrown the breaker in the house. Then we got a 30 amp extension cord and plugged it in and it ran for probably 2 hours before it did the same thing, threw the breaker in the house and the outlet was hot to the touch. Any ideas on wha the problem might be? Thanks.

Adding some to what Charlied has posted, the extension cords will cause a voltage loss and with any alternating current motor, the lower the voltage supplied, the higher current it will draw so if the voltage falls too low the circuit breaker will trip. The fact that your circuit breaker in the house tripped just shows that it was doing it's job and if it had not tripped you might have had a fire. 

If you don't have one, I strongly suggest that you buy a reasonably good volt/ohm meter and take the time to learn to use it. 

Welcome to the Escapee forums! Feel free to start your own threads in any of the forums for questions at any time. 

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

            images?q=tbn:ANd9GcQqFswi_bvvojaMvanTWAI

 

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Protection for most electrical devices are based on thermal (heat).  So, be very grateful that the devices tripped the breaker and you saw the effect before a fire started.  By your description, I would say that everything worked like it should have and prevented that fire.  Now, learn from the experience and from the input given here and dont repeat that experience.  Electricity will find the weak link and exploit it.  The greater the load, the greated the demand, the greater the heat potential.  Yes, a 100' 12Ga cord feeding your 20A AC from a 20A breaker will be affected by all that and the voltage drop in that 100' cord plus whatever distance the Romex in the house and the wiring in the coach have.  Be careful.  Using that extension cord really isnt good for anything more than running the refer before you leave, mostly because other things will run on it as well.  Need to run the AC?, use a 30A plug, breaker and 10GA cord MINIMUM and NOT 100' long!

Marcel

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Wheat Bread, you asked a good question:

 "We just brought a new to us 2015 coachmen clipper home today. We plugged in to a 12 gauge 100" 110V extension and turned on the AC. It ran fine then I turned it to high and seconds later it went off, it had thrown the breaker in the house. Then we got a 30 amp extension cord and plugged it in and it ran for probably 2 hours before it did the same thing, threw the breaker in the house and the outlet was hot to the touch. Any ideas on wha the problem might be?"

 I agree with the other gents, THE PROBLEM IS YOURE DROPPING WAY TOO MUCH VOLTAGE ACROSS THAT LONG EXTENSION CORD that reduces the voltage available at the AC itself causing it to draw more current thereby it trips the houses circuit breaker AND THATS HOW THE BREAKER SHOULD FUNCTION.

 If the RV was located closer to an outlet such that a much shorter or no added extension cord at all was necessary, you might get by running the AC subject to load and total circuit length and the breaker and actual voltage.

 The "hot" outlet is indicative of more current then its rated to handle and/or a loose burned carboned up or otherwise resistive heat producing (I Squared R) connection.

 I have ran RV rooftop AC's using a short 12 gauge extension cord to a 15 or 20 amp home outlet with an adapter BUT THAT'S PUSHING IT. Use of a 30 amp 10 Gauge extension cord or the actual RV 30 amp power cord ONLY is an improvement and even better if plugged into a 30 amp RV outlet with no adapters required like if at an RV park with a 30 amp receptacle 

  John T

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  • 3 years later...

Okay, so I have a Coleman-Mach and it's tripping the breaker ALL the time. This has been going on now for the past 3 summers. The 1st summer I limped through, then the 2nd summer came and the fan motor froze. Now it's the 3rd summer and instead of just tripping the A/C breaker, it's now tripping both the A/C and Main breaker. When I go to reset the breakers, they are very hot to the touch. Sometimes I can't keep my fingers on them. So I basically know too much current is going through them. 

I don't think it's the A/C unit itself. The 2nd summer when I had to replace the fan motor, I looked at the both the evaporator and condenser and both looked okay. Not too many bent fins and fairly clean (I was impressed by that). 

I have noticed that the fan "draws" air across the condenser and just puts it in that space where the compressor and fan motor are. I think that's piss poor design...but anyway. I also checked the capacitors. They are rusted on the top, but I didn't "see" any evidence of overheating. I.e. the tops seemed to be level. No bumps.

When it finally cools off after about 6 or 7 pm, the A/C unit runs without tripping the breaker(s). And since the whole RV is heat soaked, I turn the fan on high speed and the unit runs continuously until about 2 or 3 am. It just trips the breakers when it's hot outside. 

So my question is, ironically, not how do I solve this issue but can I use a window unit A/C during the day instead of the rooftop unit? During the heat of the day, will that still trip the breakers? Also, way back when, I use to remember that when I turned on the bathroom light I could hear a little fan start behind the breaker panel. I don't hear it anymore. Does anyone know under what condition(s) that fan is supposed to run? And what is it's purpose? (Because, to me, it's too small to seemingly have any actual usefulness)

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9 hours ago, Cliff B said:

So my question is, ironically, not how do I solve this issue but can I use a window unit A/C during the day instead of the rooftop unit? During the heat of the day, will that still trip the breakers? Also, way back when, I use to remember that when I turned on the bathroom light I could hear a little fan start behind the breaker panel. I don't hear it anymore. Does anyone know under what condition(s) that fan is supposed to run? And what is it's purpose?

Welcome to the Escapee forums. If you don't get many replies that help or have further questions, it would probably be wise to start a new thread, since this one is more than 3 years old, but I'll try to help as much as possible and maybe others will join in.

You didn't say where you are or what outside temperature you are dealing with, but it is actually quite normal for an air conditioner to draw more current when the ambient temperatures are high because it has to work harder. Depending on the condition of the a/c unit, the age and condition can also cause the current draw to increase. Looking at the service manual for a typical RV a/c unit, there are several things suggested as possible causes of the breaker being overloaded. Dirty cooling or condensing coils are there, as is poor air movement and also low refrigerant. If you share what make and model your a/c unit is, we may be able to locate an appropriate service manual for you. 

The breakers being quite warm when they trip is a very normal thing, because of the way that they work however, if the space that they are mounted becomes excessively hot that will cause them to trip at a lower operating current. That is the purpose of the fan in your power distribution panel and most of those are turned on and off by an internal thermostat. It may be that yours has failed and that would cause it to trip more frequently and with less current. It would not effect the trip point of the circuit breaker on the power pedestal, if that is tripping also. If the circuit breakers in question are very old, that too can cause them to trip at a lower power demand. The only way to be sure if your a/c is drawing too much current is to use a clamp-on ammeter while it is operating. 

Since I really don't know anything about your window air conditioner, I really can't say if it will do the job.

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

            images?q=tbn:ANd9GcQqFswi_bvvojaMvanTWAI

 

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