Roof A/C's On Generator

[HenryPatterson]

I have a 2011 Monaco Caymen 41 ft'er.

Here's the problem......with the gen running(8kw quiet diesel) I turn the airs on(2) and when the airs reach temp they turn off, when the temp raises the gen won't start them.

Turn the airs off then back on and they start fine..is it in the airs or in the gen.....????

[wolfe10]

Butch,

Let me make sure I understand the problem: When the A/C's reach temperature and turn off, ?the generator continues to run?.

But, when the thermostat signals the A/C's to turn back on, the generator:

DIES

CONTINUES TO RUN BUT THE A/C'S DON'T START

OTHER

[Keggar]

When the generator is still running, then the a/c thermostat should restart the a/c when guided by the set temperature on the thermostat.

Or, if the generator has been stopped for whatever reason: (On my coach, the a/c is not powered by the inverter.) Because the auto-gen-start is an inverter function, there is no way the generator knows to start if the thermostat signals to turn on the a/c.

[HenryPatterson]

Wolfe....the gen continues to run...no ,the gen doesn't die...just won't restart the ac's til I turn them off and turn the switch for the ac's back on.

Works fine on shore power.....gen rpm increases like its trying to start ac but goes back to idle in about 2 seconds.

Gen runs fine once ac's start and carries everything in the coach fine. Loaded up gen with everything I could think of and works fine.

[kaypsmith]

Turn one ac unit electrically off, ie. flip the breaker to that one unit, before the thermostat turns it off. Let the other turn off by the thermostat.

If the two trying to start together, are overloading the generator, the generator should start the one ac OK. If this does not occur, there may be a problem with other sources, if it does start OK, then the generator overloading with two trying to start together.

This problem could be solved by installing a time delay circuit on the second ac.

Hope this helps!

Kay Smith

[dickandlois]

Hi Butch,

Your issue is one that I have not run into yet.

With 2 AC starting OK on shore power eliminates the current sensor(s) in the AC power panel from the picture. So it should not be a shedding issue.

The only thing that comes to mind is a resistance issue that at the time only pops up under high current loads coming on all at once.

That could mean the contacts on the generator circuit breaker have oxidized a little and limit the maximum current just enough to limit the surge current or a loose connection in the J box that connects the generator cable connections to the coach cable running to the transfer switch connections.

Question, When you start the AC units manually, have you tried to start both of them at the same time? or do you start one and then the other with a short delay.

One item that might be an issue is the ground connection between the generator ground and the chassis ground point.

The other item that might cause the issue, what is your altitude and ambient temperature status. The 8K unit should run 2 -15,000 BTU AC units and have around a 3kw reserve at 100deg. and 500ft. in altitude.

Rich.

[HenryPatterson]

****... In the owners manual the book says there is a 12 sec. delay built into the system so they won't start at the same time causing an overload...With that being said, I checked and the delay is working...now with only one air on (front) it still does the same thing...gen starts the air fine..when it reaches temp the thermostat shuts the unit off....when temp rises the gen won't start it...turn the ac off with the switch turn back on and gen will start it...now not tooting my horn, but I was an Aircraft Electrician for a long time working for the federal gov't so I will find the problem if I have to replace every wire in this thing....called Monaco..yea right...they didn't even know what day it was...I do have an extended warr.but have never used it...kind-of afraid what I may get back!!! I'll do some more checking before I decide what I'm going to do...I'll keep you informed.......Butch

[HenryPatterson]

I just remembered I had the transfer switch changed due to a recall...hummm!!!!Butch

[dickandlois]

Butch thanks for the reply. Kind of makes one start thinking about the 12 volt control circuits. The other out of the box item is the thermostat circuit(s) they can cause some interesting issues! However, with the AC working on shore power it still makes one think of the power circuits and connections related to the generator.

Rich.

[HenryPatterson]

What do you think about the changing of the transfer switch? I don't remember having this problem with the old switch...Interesting!!!

[dickandlois]

That is the one item changed in the entire circuit and its not out of the realm of possibilities.

Have you checked all the ground connections and looked at the connections in the Generator J box. Over time the connections get rattled around pretty good.

If you have a IR heat gun, with the generator running under load, scan the connections in the Generator circuit; just to see if there are any hot spots.

One good last check before going through changing out the transfer Switch.

Rich.

[wolfe10]

What do you think about the changing of the transfer switch? I don't remember having this problem with the old switch...Interesting!!!

I would certainly agree with checking that all connections in the ATS are TIGHT. Obviously, with the generator off, shore power off and inverter turned off.

[HenryPatterson]

thanks guys....I'll check all the connections next week..right now we are kinda busy getting everything here back to normal or as close to normal as we can... we live in Moore Oklahoma.....I'll let you know what I find....Thanks for all the help...BUTCH