2006 Monaco, 7500w generator will run fine on it's own, and everything powers up.
Turn either of the 2 AC's on and it kills the generator once the compressors kick on. Does the same thing on a portable generator that is big enough to run just 1 AC. Plug motorhome into barn 50 amp and both AC's will run like normal. So leaning towards ruling out any AC issues. Pretty sure killed generator when microwave was on one time also. Someone local mentioned the Intellitec 30-50 amp EMS switch may be bad. Status bar did flicker a couple times as generator was powering up but seems to be functioning normal now. All breakers have been shut off and turned back on, same issue. Any other suggestions? Transfer switch was replaced 5 years ago. Invertor seems to be charging and working as should.

Capacitor issue with the ac unit?

quote:

Originally posted by Bob Payton:
Capacitor issue with the ac unit?

Thought that also, but why do they work plugged into 50amp at barn?

Barn electrical can handle spikes better but would be surprised if both units capacitors died at same time

I would suspect the EMS is causing it. I seem to remember the one I had in a previous motor home had similar issues but I can’t remember the details.

This is a tough one but common...
AC units draw a lot of amps on compressor starts.
Locked rotor amps as it's called is 3 or more times running amp draw.
With multiple items involved isolating the problem is the tough part...

Onan 7.5's are Inverter types and very complex....
Various inverters can cause issues
ATS's can possibly have issues...

No easy answer and I would approach the problem one item at a time trying to find it

They do make hot start kits for rooftop AC units that might help

It's just a capacitor really

An amp draw test at various places along the electrical path and some other tests is what I would do...

I'd start at the generator itself....disconnect it from the coach and load bank test it isolated....It should run 2 rooftop AC's no problem....has plenty of output to do it...60+ amps capable...

I've had friends ask me about similar issues and seen some AC units that were causing issues like this..

A tough one...

Take the cover off the AC units and you'll know if the capacitor is bulged or the wiring at the capacitor is fried. Happened on a 05 Monaco I was working on. Monaco and probable others reworked the wiring on them.

Put new EMS on and thought it was fixed. 30 minutes later same thing. Went to change fuel filter and dang water pump belt was shredded in access cover. What are the chances it was getting hot and shutting down? But would fire right back up.....

And once it shut off it would do the same thing with water heater or the microwave on. So should rule out AC capacitors???

What part are you calling an EMS ? The Automatic Transfer Switch ? That's known as an ATS.....connects either a generator or the shore cord to the coach isolating one from the other....automatically...
Intellitec makes a lot of stuff....obviously not the problem whatever it is...

WP belt shredding is common on an older 7.5

It will over heat and light a fault code 1 and will restart but shut down again pretty quickly...

You gotta fix that belt first, now....not an easy job unless you have a slide.....still not easy but doable without removing generator usually...

Sounds like more than one issue.....but you have to start somewhere....the belt !!

quote:

Originally posted by SCDIV1:
What part are you calling an EMS ?
Intellitec makes a lot of stuff....obviously not the problem whatever it is...

WP belt shredding is common on an older 7.5

It will over heat and light a fault code 1 and will restart but shut down again pretty quickly...

You gotta fix that belt first, now....not an easy job unless you have a slide.....still not easy but doable without removing generator usually...

Sounds like more than one issue.....but you have to start somewhere....the belt !!

Yes the 20-30-50-Gen intellitec load meter. Power bars were flashing a couple times before powering things up initially but cant seem to make it do it again. Someone thought that was it so I gave it a shot but have since talked to Intellitec and they didnt think that was the issue.
I've got the covers off then generator and easy access to pulleys.

This message has been edited. Last edited by: gd31,

Belt changed and back together.
Volt gauge plugged into one of the outlets by the dash is only reading 114v with generator running with or without a load. Seems like it was always higher than that but maybe not. Plugged into 50 amp at barn it reads 120v+.

Give me the Dummy 101 version of what to check next

Generator blinking over heat code 33 when it shuts down. Radiator flushed, spark resonator cleaned out, changing thermostat and temp sensor next. If not that, not sure what else to try. Hoses top and bottom and reservoir are all warm so assuming water pump is working as it should

There is no 33 fault code and overheat is 1's
Push stop one time when it's blinking 3's and read that code

It's an inverter/generator and there is nothing to adjust

The inverter/control section is sealed and not serviceable....

You have problems that require a service shop to check I believe...

and those inverters can be repaired by flight systems ,correct rich or do you do that service

I only recently learned Flight will repair them.
I never used them for that, always replaced the inverter/control with a new one
They were or maybe still are basically not available for months and months
It is a moot point for me anymore...

The company I worked for has been sold to a bigger generator company and they have no interest in doing shop type repairs like I did. Operations are moving to another site

I am sliding right out the door after the transition is completed.

May do some side jobs but we'll have to see how that goes....

another racer used flight and so far so good

quote:

Originally posted by SCDIV1:
There is no 33 fault code and overheat is 1's
Push stop one time when it's blinking 3's and read that code

It's an inverter/generator and there is nothing to adjust

The inverter/control section is sealed and not serviceable....

You have problems that require a service shop to check I believe...

33 is a good code for over heating per cummins manual. Changed thermostat and sensor last night and still shut down with no load. Water pump, radiator cap, and radiator itself is all that is left at this point.

No it is not....

There is NO 33 fault code...
What your seeing is 3-3-3-3-3 which is a single digit fault code indicating "service required" and there is a 2 digit fault code stored that requires you to push STOP one time to read it while it's flashing 3's

Overheating is 1-1-1-1

Low oil pressure is 2-2-2-2-

Every other shutdown starts with 3-3-3-3-3 and has a 2 digit stored as I mentioned....

The Onan controllers internally store the last fault code shutdown and it can usually be recalled by pushing STOP 3 times fairly quickly....

Trust me...I've been working on these things for many years.....

quote:

Originally posted by SCDIV1:
No it is not....

There is NO 33 fault code...
What your seeing is 3-3-3-3-3 which is a single digit fault code indicating "service required" and there is a 2 digit fault code stored that requires you to push STOP one time to read it while it's flashing 3's

Overheating is 1-1-1-1

Low oil pressure is 2-2-2-2-

Every other shutdown starts with 3-3-3-3-3 and has a 2 digit stored as I mentioned....

The Onan controllers internally store the last fault code shutdown and it can usually be recalled by pushing STOP 3 times fairly quickly....

Trust me...I've been working on these things for many years.....

So do you have any other suggestions as to why its over heating and shutting down? Disregard all the initial load stuff. I've ruled that out as it shuts down without anything on.