Weird AC 120/generator issue...

[castrol]

Okay here's a question...

2006 Monaco Knight. My folks are having some electrical issues. The main one has me stumped. I got the rest figured out.

The rooftop AC units work fine on generator but they won't kick on at all on shore power. I can hear a click in the units which sounds like they're trying...not the big click you would usually hear, but there's something going on up there.

They worked fine previously, before there was another issue with an outlet he was trying to fix by randomly flipping breakers. After the random flipping is when this issue started. Anyone every heard of anything like this? Where in the world would we start?

We thought there was an issue with the transfer switch but that seems to be working properly unless there's a separate one for the air conditioners??

[windsorbill]

Originally Posted by castrol

Okay here's a question...

2006 Monaco Knight. My folks are having some electrical issues. The main one has me stumped. I got the rest figured out.

The rooftop AC units work fine on generator but they won't kick on at all on shore power. I can hear a click in the units which sounds like they're trying...not the big click you would usually hear, but there's something going on up there.

They worked fine previously, before there was another issue with an outlet he was trying to fix by randomly flipping breakers. After the random flipping is when this issue started. Anyone every heard of anything like this? Where in the world would we start?

We thought there was an issue with the transfer switch but that seems to be working properly unless there's a separate one for the air conditioners??

can you check shore voltage? Maybe low. Be sure the prongs on the end of the shore cord are clean.

It could be the capacitor, but not likely both a/c's at once.

It might be a breaker issue since you said it started after flipping breakers. try resetting them again.

[castrol]

Originally Posted by windsorbill

can you check shore voltage? Maybe low. Be sure the prongs on the end of the shore cord are clean.

It could be the capacitor, but not likely both a/c's at once.

It might be a breaker issue since you said it started after flipping breakers. try resetting them again.

Shore power is good. He's got a Progressive surge protector on it and it is showing 121 and 123 volts on both sides.

[tinstar 1114]

What gauge wire are you using for the shore cord and what amp plug are you plugging into?

[jacwjames]

Do they have an EMS system to control total amperage draw?? If so does it show that they are hooked to a 50 amp circuit??

What if you try to run just one AC unit. Can you see if it is drawing high amps or not.

You might try cycling the generator on off a couple times and see if it makes a difference with the transfer switch. The transfer switch may not be fully connecting on shore power.

[u04601]

Make sure the house 12vdc switch is turned on. My Tiffen needs that for the AC to turn on.

[rag_ftw]

Sounds like you have good power to the coach. Since neither ac wants to kick in my guess is the starting capacitor is not getting enough amps for the initial start. If you have a Kill-A-Watt this would be a good time to break it out.
https://eshop.macsales.com/item/P3%2...zDPxoCYuvw_wcB

This is what I would check in this order:
1. Check all ac breakers again to make sure they are indeed on and working correctly, since this is when the problem started.

2. Make sure the EMS didn't reset to 20 amps during all the switch/circuit breaker operations.

3. Measure voltage at several outlets inside the coach.

4. Try to load up the system without running the ac to see if the problem is with the ac units or with the coach ac power circuit. Turn on clothes dryer, hair dryer, microwave, elec skillet, etc to get above a 30 amp draw and see if they all work.

5. If you can pull 30-40 amps with no problem I would start looking for a problem with ac units. I just find it hard to believe both would go bad at the same time.

[castrol]

So a coach tech had him remove the panel around the breaker box. Unplug the connectors that run to the "brain" where the switchover happens between the generator and the shore power. Leave them unplugged for about 10 minutes and then reconnect everything.

This seemed like a ridiculous request, but it worked. I'm flabbergasted.

[markmcc1776]

Do you have a photo of what connectors? Goid to know. Thanks

[castrol]

Here's a video to help out. This totally fixed the issue which I admit, was a very odd one.

http://vid30.photobucket.com/albums/...psqdhi1hyq.mp4

[Dr4Film]

The board where those three connectors are attached to is called an Intellitec EMS Control board (EMS = energy management system). That board controls your devices which are allowed to run when you are on shore power LESS than 50 amps.

When on 50 amp shore power that board is in bypass mode.

When on 30 amp or less shore power then this board comes to life and starts monitoring the number of amps you are using to make sure that you don't go over whatever amps your shore power is supplying. Once you are close to the limited amount of amps you have available to use that board will start shedding devices in the order that is written on your EMS Display Panel.

My shedding order is Water Heater - Rear A/C - Washer/Dryer - Front A/C followed by two 12 VDC control systems which are usually the 12 VDC A/C controls for the A/C Thermostat(s).

Sometimes that board brain goes dead and will do some pretty strange stuff like tell you that you have 30 amps when you are really hooked to 50 amp shore power, screw up your A/C's (as you found out) show some strange lights on the display at times that don't make sense like the GEN light comes on when on shore power, etc.

Glad you found the problem!

Dr4Film ----- Richard