Generator not powering air conditioners

[Clarabelle]

My wife and I just returned to Houston from a trip to Las Vegas in our 2003 American Tradition.  Sometimes I run my generator when stopping for lunch just to give it a workout.  On this trip I started the generator and turned on one of the roof airs.  Nothing.  The air works fine when plugged into AC.  Any ideas as to why I am not getting juice to the air conditioner?  Thanks. ???

 

[John From Detroit]

You said "One of the roof airs" may I assume the other one works off the generator just fine?

What generator do you have (I have an Onan 5500)  Many generators have a lovely PAIR of circuit breakers, look to all the world to be 240 volt generators but alas, they are 120, Just two legs (Circuits)

Odds favor one of those breakers being in the tripped position,  Can happen due to vibration of driving down the road

 

[Clarabelle]

Actually, neither of the roof airs work on generator.? I checked the breakers and they are not tripped. The only thing that I have done lately is to turn off the inverter system.? I wouldn't think that the inverter would have any relationship to the generator powering the air.? I wonder if it could be anything to do with the auto-on system (that I keep turned off)?
? ???

 

[Terry A. Brewer]

>>Actually, neither of the roof airs work on generator<<

Are any AC items working, like your micro-wave?...If not check your transfer switch as their relays are prone to failing.

 

[John From Detroit]

If no AC items work on the generator (note if you have an inverter then some will work even if the generator is not running) check BOTH the breakers on the generator, also chek your transfer switch.... My 2005 came with a factory installed transfer switch that did not last 3 months

 

[Clarabelle]

OK, I'll check the manuals and see if I can locate the transfer switch.  I already checked the switch on the gen and it's on.  Thanks.

 

[John From Detroit]

In my case the manuals did not help me to find the switch... Logic did, but it was not mentioned in the manuals

It was also hidden... but it was hidden in a logical place, so I found it

 

[Clarabelle]

I wouldn't know it if I tripped over it. :

 

[Gary RV_Wizard]

Your first step will be to determine if ANYTHING can be powered from the generator. With the genset on, plug something (e.g. a table lamp) into one of your regular 120 VAC wall outlets and see if it works.  Whether yes or no, try a few other outlets to see if any others are affected differently.  Also note whether your refrigerator switches to 120 VAC operation with the genset on or if it stays on LP. If nothing else works, then we need to investigate the generator output and transfer switch. If all of the other stuff works, then we need to look at the air conditioning power source(s) and do some further diagnosis. If some but not all of the other stuff works, further analysis will be required based on what you find..

 

[Karl]

Gary, I agree with you. Until we have more info on what works on generator power and what doesn't, we're pretty much at a standstill.

Just one small thing: If the AES (automatic electric sensing, I think) for the refrigerator is not in the "automatic" mode, it won't switch from gas to electric even if AC power is present. Make sure the "AES Auto" light is lit; it should switch back and forth between "AES Auto" and "Gas" with each press of the switch.

 

[Clarabelle]

OK.  I will check those thing out tomorrow and let you know what I find out.  So far I just tried the TV and air conditioners.  I'll check out the fridge, etc..  Thanks.

 

[John From Detroit]

Suggestions for finding the auto-switch if it is not explained in the manual.

I have, of course, opened every cubbord door, every drawer, and every compartment in my motor home (Anyone here who has not at some time or another) and peaked inside.  Near the generator (one comparment away) there is what is very obviously an electrical conduit (at least to me) big gray box and hose.

That is, in fact, the generator output line

As it happens it is not far from my breaker box... So, I figured the transfer switch had to be somewhere inbetween.  And in my case there is a cabnet, just above the Generator's output pipe where there was a block off panel keeping me from using most of the cabnet... Removed the panel and there was sometihng with "Intella-xxxx" on it if memory serves... (I think it is an Intella-Power brand but am not sure) note, there are other brands as well.  (Checked two web sites could not find one0

This box had very heavy power cables (3 of them) coming into it,  Generator, Mains and the third was actuallly an OUTPUT to the breaker panel

So, look in cabnets near the power panel (Mine is about  is 3 feet behind it)

 

[Karl]

Clarabelle,

You STILL haven't told us if any AC appliances work! We need to know that if we're to help you.

 

[Clarabelle]

I tried and nothing is receiving power from the generator.  I will look for the switch box.  I won't be able to get to my coach again until Saturday. I'll post my findings.  Thanks.

 

[John From Detroit]

I tried and nothing is receiving power from the generator. 

That indicates one of three conditions

1: Circuit breakers on generator are really OFF, not ON (I wish they labeled them better and one day I will)

2: Auto-Transfer switch fried ( In my case, this was it, They replaced under warranty, handy that I had a service appointment for the next morning for another warranty issue(

3: Generator fried

Note; when you find the switch, simply remove the cover (with generator off and shore power UNPLUGED)

The connections should be labeled.  Fire up generator and measure voltage at the GENERATOR connections, NOTE, generator is likely 120 volt so the two "HOT" legs are in phase and will read zero volts. Measure "hot" to Common.    Then to be sure plug in shore power and measure the "mains" leads... these may be 240 volt so be careful

 

[Karl]

Clarabelle,

Here is a link to the Intellitec transfer switch manual. Please print it out. Later today I will post another message with step-by-step instruction for using it to determine where your problem is. Hopefully you have this particular model of switch, but even if you don't, it will serve to identify the voltages we expect to see at specific points and at specific times (genset running/not running, shore power plugged in/not plugged in, etc). Become familiar with the various labels/names of the connections, but don't try to figure out how the circuit operates - it's not necessary for our purposes.

http://intellitec.com/PDF/5300803.100.pdf

Karl

 

[Jeff]

Carabelle:

At some point when all the techies here have you uncovering 240v connections remember you have the option of having someone who knows what they are doing check it for you. ;D ;D

 

[Karl]

Jeff,

Somewhere,somehow, sometime, when you least expect it.......

 

[Gary RV_Wizard]

Clarabelle,
You mentioned the breakers were not tripped, but did not specifiy that you looked at the breakers on the genset itself.  The a/c breakers in the inside power panel (load center) must be OK since the a/c runs on shore power, but the genset breakers (usually right on the genset itself) are separate and affect only generator output. Double check them and just to be sure, flip them off and back on again. 

 

[Clarabelle]

OK.  Thanks.  I'll be at the motorhome tomorrow and check it out.