AC only running on shore power not generator

[Southwind2003]

Hello, our 2 AC units won’t cool. AC1 doesn’t blow fan, cool, or shed. AC 2 blows fan, doesn’t cool, and shed light stays on .
When hooked to
Shore power it works fine .
We just installed
New transfer switch, generator fixed. When generator is on we have power in RV just not AC units working properly.

2003 south wind fleetwood 35 ft.

 

[UTTransplant]

Check the breaker on the generator itself. That’s what causes this result in our rig.

 

[Kirk]

Have you checked the circuit breakers for the a/c units on the 120V power distribution panel?

AC1 doesn’t blow fan, cool, or shed. AC 2 blows fan, doesn’t cool, and shed light stays on .

That sounds like you have a problem with the electrical power management system. "Shed" means the EMS (Electrical Management System) is turning off one of the power hungry A/C compressors to keep the power consumption down.

 

[Southwind2003]

We have tested all fuses , breakers , we did the test switch and both units just turn on fan high . No compressor kicks in.

 

[Southwind2003]

Check the breaker on the generator itself. That’s what causes this result in our rig.

Yes breaker is not tripped

 

[Southwind2003]

Have you checked the circuit breakers for the a/c units on the 120V power distribution panel?

That sounds like you have a problem with the electrical power management system. "Shed" means the EMS (Electrical Management System) is turning off one of the power hungry A/C compressors to keep the power consumption down.

How do I verify if it’s the EMS ?

 

[Southwind2003]

Have you checked the circuit breakers for the a/c units on the 120V power distribution panel?

That sounds like you have a problem with the electrical power management system. "Shed" means the EMS (Electrical Management System) is turning off one of the power hungry A/C compressors to keep the power consumption down.

We have ECC not EMS

 

[PancakeBill]

If it works fine on shore pwoer and not on generator and generator powers everything else OK, I would suspect the EMS. I had to replace mine in my Southwind. Got lucky and found a replacement.

 

[Southwind2003]

If it works fine on shore pwoer and not on generator and generator powers everything else OK, I would suspect the EMS. I had to replace mine in my Southwind. Got lucky and found a replacement.

I have ECC not EMS

 

[Larry N.]

Is that ECC "Electronic Climate Control?" Does the "shed" light appear on that ECC panel (not in the ones I've seen)? You might have both, since they are different functions unless your ECC is not what I expected such a designation to be.

And if you have "shed" for A/C then you likely have it for certain other major power using devices, too. In any case, "shed" generally just means that whatever control device that did that sensed that you needed to reduce power usage to avoid excessive flow to pop breakers and such.

 

[Southwind2003]

Is that ECC "Electronic Climate Control?" Does the "shed" light appear on that ECC panel (not in the ones I've seen)? You might have both, since they are different functions unless your ECC is not what I expected such a designation to be.

And if you have "shed" for A/C then you likely have it for certain other major power using devices, too. In any case, "shed" generally just means that whatever control device that did that sensed that you needed to reduce power usage to avoid excessive flow to pop breakers and such.

Yes it shows the shed light on the penal . See attachment this is what I have .

 

[Southwind2003]

Yes it shows the shed light on the penal . See attachment this is what I have .

We turned off all appliances and just ran one AC unit and it didn’t same. .

 

[Larry N.]

Yes it shows the shed light on the penal . See attachment this is what I have .

OK- not exactly what I remembered, but that "shed" light is obviously intended in the same way as the EMS would have for things that are "shed." Thanks for the correction and education.

 

[Gary RV_Wizard]

The ECC "shed" light is a major clue. It thinks power is limited to 30A total and its amp-monitor has detected a total load approaching that limit. It may be mistaken about that due to a faulty input, but that's just a different cause for the same problem/symptom.

Tell us more about your generator, i.e. make & model and power output (wattage). Coaches of your year & size typically have a 5000-5500 watt generator with two output circuits, one 30A/120v and one 20A/120v, each with its own breaker. A tripped breaker could trigger your symptom. So could a faulty transfer switch or a loose wire.

The ECC can also get confused if one of the main panel breakers is turned off. The lack of voltage on one circuit can cause the ECC amp/volt monitor to make an incorrect conclusion. Make sure all breakers are on.

 

[Southwind2003]

The ECC "shed" light is a major clue. It thinks power is limited to 30A total and its amp-monitor has detected a total load approaching that limit. It may be mistaken about that due to a faulty input, but that's just a different cause for the same problem/symptom.

Tell us more about your generator, i.e. make & model and power output (wattage). Coaches of your year & size typically have a 5000-5500 watt generator with two output circuits, one 30A/120v and one 20A/120v, each with its own breaker. A tripped breaker could trigger your symptom. So could a faulty transfer switch or a loose wire.

The ECC can also get confused if one of the main panel breakers is turned off. The lack of voltage on one circuit can cause the ECC amp/volt monitor to make an incorrect conclusion. Make sure all breakers are on.

Hi Gary , so we have checked fuses, breakers inside and outside to the generator . we did the the test switch . We have a 5500 Onan generator . We have the 120/30amp . We just got the generator fixed because it was not giving any power at all previously. We just replaced the transfer switch . We can hear the transfer switch turn over when we turn on AC . We have a 2003 fleetwood south wi d 35 ft . This issue is only happening when on generator . It works great on shore power .

 

[Gary RV_Wizard]

Your symptom is similar to what I'd expect if your generator had only the single 30A/120v output. What about a secondary output, which would probably be rated 20/120v?

Check the output from the transfer switch while using the generator. It should show voltage on both of the hot legs that feed to the man power panel (breaker box). Since the transfer switch was just replaced, the generator side could have been miswired or a wire is loose.

And just to be sure, can you confirm the coach has 50A shore power, i.e. it uses a 4-prong plug to connect? The generator and transfer switch are different for 30A vs 50A systems.

 

[Mr Lars]

Did the a/c’s work on generator in the past?

 

[Southwind2003]

no secondary output , I will get back to you Thursday for the voltage in the legs from
Gen to transfer switch . From
What the generator tech said when he put the generator back In he said all voltage was good. So we can verify that Thursday. Wires are correct and not loose. We dont have 50a shore power.

 

[PancakeBill]

ECC is what I had as well. Transfer switch should activate when gen starts up or soon after.

 

[Southwind2003]

ECC is what I had as well. Transfer switch should activate when gen starts up or soon after.

Yes and we hear that click on