2 air conditiomer units on a 30 amp sevice

Discussion in 'Beginning RVing' started by boeing46, Jul 19, 2007.

  1. boeing46

    boeing46 New Member

    My 2003 Fleetwood Flair has two a/c units on the roof. The plug for my coach is 30 amp. I read on an ask the rv Doctor question and answer column that with a 30 amp service only one a/c unit should be run at at time when plugged in to shore power. It says it is ok to run both when useing the generator. I noticed after unplugging from an RV site last month one of the blades on the 30 amp plug was dis-colored. I have seen that many times and it is an indication of to much heat or over draw. The a/c units draw 13 amps each. The thermostate manual says when to much amperage is drawn one of the units shed.
    Should i trust this automatic feature or turn off one unit while using other 110 volt devices? I do not know what the fridge draws when the compressor kicks in but i would assume it would exceed the 30 amp max with both a/c units running.
    In hot weather the fridge is going to be running allot. If somebody is familiar with the proper way to deal with this situation I would appreciate it.
     
  2. hertig

    hertig Senior Member

    Re: 2 air conditiomer units on a 30 amp sevice

    Also, I bet it pulls more than 13 amps on startup. There is a gadget which sequences 2 A/Cs so that they don't both draw at once. I'd either turn off on at a time, or get that gadget.
     
  3. Guest

    Guest Guest

    Re: 2 air conditiomer units on a 30 amp sevice

    I agree with hertig ,, here is some thing i did to my class A ,,
    I updated it to 50 amp ,, but the other leg of my 120 volt i ran to the rear ac only ,, that way when i'm plugged in via shore line i can run both a/c 's at the same time,,, the way my coach was wired i could only run 1 a/c at a time while plugged in ,, but could run both via the genset,, i had a a/c switch in the coach that was wired so that if the switch was down then the front a/c ran ,, if i switched it up then the rear a/c ran ,, but i didn't matter where the switches were when i ran on the genny,,,
    Anyway if u want to know how to setup u'r rig this way post me back and i'll give u the insight ,, (if u'r not afraid of a few electrical shocks :) and some new wire pulling thru the walls)
    :laugh: :laugh:
     
  4. boeing46

    boeing46 New Member

    Re: 2 air conditiomer units on a 30 amp sevice

    I have done electical work since i was 12 working side jobs with my Dad. I have been an electrician my entire working life. I could easily upgrade to 50 amp but i injured my back to the point that i am dissabled. I was just kind of fishing for advice of how others deal with this problem.
    I think if i start one, let it run and then start the other i would be fine. My only worry is the draw from the fridge.
    I think if it gets very hot i can run both and run the fridge on propane. If i need to run the microwave or anything with a high amperage draw i will turn of one a/c unit. 26 amps is pushing the limit but when its real hot my experience when i had one a/c unit on a fiver i had it didn't come close to keeping us cool. There are tricks that i could do to isolate the 2nd a/c and use the other leg of the 50 amp supply at a camp site. It would not be a normal set up but it would be safe and funtional. Thanks to all!
     
  5. hertig

    hertig Senior Member

    Re: 2 air conditiomer units on a 30 amp sevice

    Your manual solution may work, but I think it would be risky. If you ever forgot and both A/C's tried to start at the same time, it could get messy. And what if the converter kicked in?

    I think that sequencing device would probably be the easiest. Converting to 50 amps with the second A/C on its own leg might be the 'best' solution, but leaves you without the second A/C if 50 amps is not available
     
  6. Guest

    Guest Guest

    Re: 2 air conditiomer units on a 30 amp sevice

    very true hertig ,, and i agree that if both a/c kick up to full power :eek: :eek:
    also as for my unit ,,, if 50 amps is not available i use my adapter from 50 to 30 which i use any on the plug for the genny and run only 1 unit (it gets cool enough for me ,, but i like heat )
    but anyway i think i also am going to look into a sequencer thingy too :bleh: :cool: :laugh:
     
  7. Kirk

    Kirk Senior Member

    Re: 2 air conditiomer units on a 30 amp sevice

    First of all, the discolored pin on your power plug doesn't always mean that you are running too much current for the circuit. It is very common for RV parks to have old, weather worn power outlets that have spread to the point where the pins of a power plug do not fit tightly. A loose connection will cause the pins to get hot and can even melt the plug it's self in extreme cases. That can happen with even moderate loads. What will happen if you draw too much current for the 30A plug is that the circuit breaker will trip. It is true that with two air conditioners you will likely be very close to that limit, but if the breaker does not open you have not exceeded the rating of your power pedestal. Increasing the power demand does increase the over heating problem but it is not the cause of it if the breakers are not opening. If you have just a typical RV thermostat, it won't do anything to balance the load by dropping off one of the air conditioners, but you may have a power management system that will do that. You didn't say what make or model of RV you have but it sounds as though yours has a power management system, and if so, they do work very well. To say for sure what you should do, we would need to know just what it is that you have.

    I would strongly suggest that you watch the outlets you plug into closely. Also, make sure that your voltage does not begin to drop as you add add loads. Under voltage can be a very serious problem when operating 120V-ac motors.
     
  8. DL Rupper

    DL Rupper Senior Member

    Re: 2 air conditiomer units on a 30 amp sevice

    Read what Kirk says about under voltage carefully. Most RV park voltage drops as the appliances are sequentially turned on. We use an Autoformer to boost the voltage back up to the safe zone (110 V or above). Low voltage reduces the life of your appliances significantly. Especially air conditioners.

    I believe there are about 2 or 3 other manufacturers that make the voltage boost transformers now besides the Autoformer brand.
     
  9. Guest

    Guest Guest

    Re: 2 air conditiomer units on a 30 amp sevice

    where can i get one of those sequencing devices for my a/c ,, i have checked PPL and Stagparkway ,, but they don't offer them :(
    Oh yea bty my a/c units are not on thermostats they are what we call at the shop dumper units (they blow directly into the coach via the vents on them) :8ball:
     
  10. hertig

    hertig Senior Member

    Re: 2 air conditiomer units on a 30 amp sevice

    Thermostats are what turn the units on and off per the temperature at the thermostat location. Ducting is what blows the cold air at some other location than from the unit itself. Will see if I can find any source of the sequencer. Perhaps they have been discontinued.
     
  11. Kirk

    Kirk Senior Member

    Re: 2 air conditiomer units on a 30 amp sevice

    There are companies that build power management systems for RVs. I can't tell you who they are but I do know that many Fleetwood products and some Winnebago products do have them. If anyone here has an RV with one they may know who made it. I suspect that the main reason we don't see them in the after market is the fact that it would require rewiring of the RV to install one. All of the larger loads would have to be connected to the power supply through that management unit or have a relay in the line which it controlled. It could be done, but it would be expensive and it would take a lot of work. A much better way would be to get one of the power boost systems such as sold by Autoformer or Frank's Electronics or you could also get a line monitor from either Surge Guard or from Progressive. Those products protect you by removing power.
     

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