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Old 03-02-2018, 11:29 AM   #1
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Two ACs will not work at same time

Suddenly only one of our two air condtioners in our motorhome will run at a time. I have to manually turn one off before th other one will come on. Nothing has changed. Been working with both for weeks. Am plugged into 50 amp. What could be problem?
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Old 03-02-2018, 11:36 AM   #2
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Do you have a panel somewhere that tells you where the power is coming from?
If so, did that panel somehow get changed to either 30amp or 20amp?
That would cause the EMS to start load shedding, thinking that there isn't enough incoming power to handle both AC units.
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Old 03-02-2018, 11:41 AM   #3
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What is AC Source VOLTAGE?
Is it time for YOUR Medication or Mine?
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Old 03-02-2018, 11:45 AM   #4
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Have you just changed parks? Low voltage at pedestal? Has the park recently filled up with more RVs? Weather suddenly hotter?
Any of these events can result in low voltage at the pedestal.
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Old 03-02-2018, 11:45 AM   #5
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Excellent point O-B (as always!).
Which also makes me wonder if there is power on both the the 'hot' terminals at the pedestal.
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Old 03-02-2018, 12:44 PM   #6
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Same park ? Pull plug and check for bad connection. Plug it in and out a few times to clean it.

Different park ? May be fake 50 amp. Is it an old park, they sometimes cheat and do 50 amp 120 volt instead of rewiring for 50 amp 240 volt. MH will act like its connected to 30 amp.
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Old 03-02-2018, 12:50 PM   #7
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yes, you've either LOST one leg of your 50a double-pole line, OR your coach 'thinks' you have, therefore limiting your AC simultaneous usage.

check the power pedestal 50a breakers - could it be that 'one' side has tripped, and not the other? Odd, but odder things can happen. While a double-pole 50a breaker has a 'connector' between the two to trip both at the same time, I've seen them without this, probably from the 'bother-in-law' is my electrician scenario!
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Old 03-02-2018, 02:04 PM   #8
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Could it be he lost one of his 30 or 50 amp contactors in his transfer box, maybe it is not pulling in, maybe a bad coil?
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Old 03-02-2018, 05:35 PM   #9
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Hi ! Welcome to IRV2! We're sure glad you joined the gang!

Are you using a multi-zone thermostat? If so, does it show both zones at the same time? You may need to do a reset.

Good luck, happy trails, and God bless!
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Old 03-02-2018, 05:58 PM   #10
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Only One AC

Had the same problem a few weeks ago, found out i had lost my Neutral leg on my cable going from the Pedestal, from all the handling of the Plug , a screw in the plug had come loose and the wire had pulled loose from the plug. Simple fix , reattach the wire in the plug . Easy to check get a meter, and check your breaker panel connections go from your hot legs to the neutral the white wire , should have 110 on both legs if nothing there neutral is open. This means you are getting 220 at the ACs with no ground ,mine did the same thing ! Can cause many problems with all your other appliances if not fixed !
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Old 03-05-2018, 05:20 PM   #11
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Just went through this, it was my hard start capacitors, one was burned!!! Hope this helps
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Old 03-05-2018, 06:45 PM   #12
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Originally Posted by Old-Biscuit View Post
What is AC Source VOLTAGE?
Alternating Current Source Voltage, such as the shore power.
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