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Topic: No 30 amp Shore Power ? (Read 1542 times) previous topic - next topic

No 30 amp Shore Power ?

I have a 1999 U320 that I purchased June of 2021. I use my U320 to pull a race trailer and for the most part, all has been well. There have been two times now, when I needed to run the Pro-tech 10K generator it would not run - I was able to fix the generator both times once I got home.
In my race trailer I have a Honda EU3000 generator with a 125v/30 amp twist lock outlet. I have the dog bone adapter to go from the 30 amp outlet of my Honda Generator to my 50 amp extension cord that also has the weatherproof twist lock end to plug into the motor home.
The plug end at the motor home has a red LED light indicating power at the motor home plug connection. This red LED is always illuminated when plugged into to  a 50 amp shoreline connection and I have full power inside the motor home. I also show 125 volts on L1 and L2 inside on the display.
When I source power (30 amp) from my Honda generator I have no Red LED light at the motor home plug, no power on L1 and L2 on the display and no power inside the motor home to operate one AC unit ???
I checked for voltage out of the Honda Generator, through the dog bone adapter and at the motor home plug all is good (still no Red LED light at the motor home plug).
 I've never had the motor home plugged into a shoreline 30 amp outlet only my 30 amp outlet on my Honda generator.
What am I missing ? What am I not seeing ?

Tom

Re: No 30 amp Shore Power ?

Reply #1 –
If your coach has an EMS SYSTEM. you may have to make up or purchase a neutral bonding plug that fools the motor home surge protection. Search the  web or I'm sure someone here will chime in. You can make your own by using a 110v male plug and connect the ground (green) terminal to the neutral (silver) terminal. DO NOT CONNECT ANY THING TO THE GOLD OR BLACK TERMINAL. Or can buy them for about 10 bucks.

Re: No 30 amp Shore Power ?

Reply #3 –
Great answer guys. To add to this even if you had 240v at generator you need to make sure there is continuity between neutral and ground.  Same problem if power pole is wired wrong .

Re: No 30 amp Shore Power ?

Reply #4 –
I wonder if that solved his issue

Re: No 30 amp Shore Power ?

Reply #5 –
I have not had the time yet to see if the bonded plug works. I will let you know - thanks Tom.

Re: No 30 amp Shore Power ?

Reply #6 –
Update - I installed a bonded plug in one of my 15 amp outlets on my Honda Generator, then installed the dog bone adapter into the 30 amp outlet and plugged in my 50 amp cord from the motor Home. I now getting power into the motor home 😁 The fridge runs, the HVAC fans run and I see L1 and L2 line voltage (125v) on the display.

I noticed I still do not have the Red LED power indicator light on the 50 amp extension cord where it plugs into the motorhome and I cannot get either of the AC units to turn on ? In regards to the HVAC zones 1 & 2 everything works with 50 amp shore power input or the onboard ProTech 10k Generator. With 125v/30 amp input from my little Honda EU3000 Generator the thermostat control seems to be able to operate everything except it will not turn on zone 1 or zone 2 AC cool ? Zone 1 & 2 fans work in fan only mode in low and high speeds and can run both zone fans at the same time.
Does anyone know why the AC units won't attempt to even start up ?

Re: No 30 amp Shore Power ?

Reply #7 –
If that EU3000 actually produces 3000W @ 30amps, Ohms law shows that will only provide 100Volts at that max wattage.
I'm not sure of what kind of amperage spike one AC starting up would draw. But that little gen might be at it's max or beyond just starting up the AC. Never mind if you have lights and a fridge going as well. Even if you remove every load you can to get the AC started. It will still have issues when the AC cycles with the thermostat setting.

But of course I could be wrong.

Re: No 30 amp Shore Power ?

Reply #8 –
I have never seen a red light on a 50 amp cord.  Looks like the light requires 240V in order to operate, while with that generator you only have 120V

The generator specs say it can output 25 amps at 120Volts and it can handle most RV  13,500 BTU AC units.

Have you tried turning everything else off, and only trying to start the rear AC unit?

Have you tried with the generator Eco throttle switch off where the motor is running at the high rpm?

Re: No 30 amp Shore Power ?

Reply #9 –
I believe I had every electrical draw turned off when trying to start the rear AC unit. I will double check tonight and make sure that I had the fridge turned off ? I did have the "Eco" switch turned off on the Honda generator.

I may have to invest in a "SoftStartRV product.

Re: No 30 amp Shore Power ?

Reply #10 –
Were you able to hear the compressor trying to start?  On a regular generator you would be able to hear the engine dragged down when a compressor tries to start, but don't now how an inverter generator would handle it.

I saw where someone had a Bluetooth  on his soft start.  He  was able to see what the starting load was and it was less then the running load by a few amps.  I was impressed that it made that big of difference for the starting load to be less then the running load.

Re: No 30 amp Shore Power ?

Reply #11 –
When I placed the thermostat on cool - zone 1 or 2, I heard nothing. No compressor trying to come on. No draw on my Honda Generator ?

Re: No 30 amp Shore Power ?

Reply #12 –
I have not seen this device on Foretravel before,  but there is a device that checks the amount of power coming in a coach (it looks for 240v and if it only sees 120V is defaults to what the 120V default is which could be 15-20-30 amps)  and it then decides if the AC can run the compressor or not.  It has a control wiring going to the control board of each AC unit it operates. I have seen these things go bad.  If you go to the control board up on the roof,  you can bypass that feature.  It is possible that if this device is on this coach that it does not like the quality of the power to allow the AC compressors to kick in.

For the fans to run, it means that there is power to the units.

Have you tried the microwave to see if it will work?

Re: No 30 amp Shore Power ?

Reply #13 –
Quote from: Tboy66 –
When I placed the thermostat on cool - zone 1 or 2, I heard nothing. No compressor trying to come on. No draw on my Honda Generator ?
Did you leave it on for some time? Mine (1998 U320) are at times ponderously slow to respond to the thermostat when I first switch it to cooling.

And of course, Make sure that the two zones are not in conflict. One needs to be off or on the same setting as the other zone. I often overlook this and I'm sat scratching my melon. Then the light goes on.

Re: No 30 amp Shore Power ?

Reply #14 –
Bigdog,
I tried to start up zone 1 AC (zone 2 off) first then tried the opposite. I did wait a few minutes in each configuration for AC start up but it never came on. 

Re: No 30 amp Shore Power ?

Reply #15 –
Update
So, last night I tried again to start up one of the U320 AC units using my small Honda EU3000is generator. I definitely had all other electrical draws turned off and then turned on zone 1 AC cool mode. I patiently waited, and 5 minutes later the AC unit started up ! I shut off zone 1 and selected zone 2 AC cool mode, and again, 5 minutes later it also started up !
I don't know why it takes so long (5 minutes feels very long sitting there waiting for something to turn on) but it is working.

Thanks to bbeane for the neutral bonding plug suggestion. Ultimately, that was the solution to my problem.

Re: No 30 amp Shore Power ?

Reply #16 –
My ACs also have the delay when first turned on.

Re: No 30 amp Shore Power ?

Reply #17 –
Quote from: Tboy66 –
Update
So, last night I tried again to start up one of the U320 AC units using my small Honda EU3000is generator. I definitely had all other electrical draws turned off and then turned on zone 1 AC cool mode. I patiently waited, and 5 minutes later the AC unit started up ! I shut off zone 1 and selected zone 2 AC cool mode, and again, 5 minutes later it also started up !
I don't know why it takes so long (5 minutes feels very long sitting there waiting for something to turn on) but it is working.

Thanks to bbeane for the neutral bonding plug suggestion. Ultimately, that was the solution to my problem.

WOW! That is a very long delay. And I thought mine were sometimes slow to respond.

Great result though. Hard to live in a sweat box.

Re: No 30 amp Shore Power ?

Reply #18 –
My understanding about A/C delay:

Air conditioners may have a timer that can delay compressor start.  Air conditioner systems compress refrigerant-gas which is plumbed to the evaporator-coil (the part that cools). The hot gas turns to liquid state in the evaporator, absorbing heat, then flows back to condenser-coil which removes the heat and turns the liquid back to a gas.

The compressor cannot compress refrigerant when it is in the liquid state. There is a time after compressor turns off where liquid may be where the system expects gas, so the timer tries to give the system time to adjust.

I think of the delay as a compressor protector.

Re: No 30 amp Shore Power ?

Reply #19 –
My 2cents.
I think you may have it backwards, Barry.
 Liquid arrives at the evaporator where it picks up heat,  boils and evaporates to a gas.  Hence the name evaporator.  I believe a change in pressure may also happen but not positive.
 The hot gas returns outside to the condenser where excess heat is removed (by the big whirly fan thingy) and the very large surface area of the coil.  That's why the condenser has so many fins.
 The compressor then returns the cooled liquid back to the evaporator to repeat the process.