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Author Topic: AC will not work with shore power but does with genset  (Read 282 times)

EZY1968

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AC will not work with shore power but does with genset
« on: September 13, 2017, 01:15:07 PM »
I have a 2006 Monaco La Palma with 50 amp pigtail. The hot water and 2 roof top AC units were working with shore power but after a recent trip they will not work with shore power only with the genset running, all the other 120v appliances work with shorepower ( Microwave, plug in's, ETC ). I do have 120 volts to the 2 breakers at the main disconnect. When the genset is running there is a light on in the " Switcher " .... where the genny, shore power come in and then the power out to the breaker box.  Not sure what's going on.
Any help work be great !!! :-\

John From Detroit

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Re: AC will not work with shore power but does with genset
« Reply #1 on: September 13, 2017, 06:08:21 PM »
Mulltiple suspects.

In line order
Are you sure the 50 amp outlet you are plugging into is live?  (Test it)
next test at the Marinco Outlet (the part that plugs into the sice of the motor home)

Next stop is the Automatic Transfer Switch  and that. I might add is a PRIME SUSPECT

Things I have found: Loose screws (plug if not welded), Marinco outlet (two different RVs) Marinco Inlet (MY RV) breaker box (MY RV)

Auto Transfer Switch:  These are NOT designed to switch under load it seems. especially an INDUCTIVE load such as the air conditioner motors.

SHUT DOWN (TUrn off park breaker and unplug for 3 minutes before starting Generator, or shut down generator for 3 mintues before plugging in or turn off MAIN breaker in RF for 3 minutes when changing source)

What can happen if you switch under load is you can weld the contactors into one or the other position and it won't transfer.
Nothing adds excitement like something that is none of your business
My Home is where I park it.

Gary RV_Wizard

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Re: AC will not work with shore power but does with genset
« Reply #2 on: September 14, 2017, 09:26:13 AM »
You state that other 120v appliances work on shore power, so that would seem to eliminate a few of the things John suggested. However, it could be that you are only getting half of the 50A shore power, i.e.one of the two "hot" circuits is not connected or not getting through the transfer switch.

What does the "light on in the switcher" indicate, and is it also on when plugged to shore power?
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

EZY1968

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Re: AC will not work with shore power but does with genset
« Reply #3 on: September 14, 2017, 09:52:09 PM »
Thanks a bunch for the responses, John and Garry ..... great information. John I did test the 50 amp and I do have 120v on each of the red and black phase. I don't have a " Plug " as stated mine is hard wired into the switch box. I will try to get at the box to look for loose connections , corroded broke over the weekend. I was not aware about the load part, ran the genny once every couple weeks to for a few hours to give it work out while plugged into shore power. That might have done it. CRAP !!!!

Gary I did notice that there is a green light ( in the switcher )when the genny is running but not when the shore power is on??? sounds like it should be too? Correct?
 8)

Gary RV_Wizard

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Re: AC will not work with shore power but does with genset
« Reply #4 on: September 15, 2017, 11:05:47 AM »
Without knowing what "switcher" you have, I don't have a clue what the green light means or when it should be on. Can you repolrt a brand name & model for that box?  A typical auto-transfer switch (ATS) has no lights at all, but an ATS with built-in power monitoring typically will. If that's what you have, then the lack of a green light with shore power is probably significant. For example, you may have a Surge Guard or Progressive Industries power monitor as part of the ATS or hardwired to it.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

 

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