# Yamaha Ef2400Is Generator Will Not Run 13’500 Ac



## santurinos (Aug 1, 2010)

We finally bought a Yamaha EF2400iS generator for our Trail-lite crossover 189QB with a standard Carrier 13'500 BTU A/C. 
The camper and AC unit are 2008 model but never used before.
I did a search on Google and read many positive contributions about running a 13'500 RV unit with the EF2400iS.

But the generator will not run the a/c unit, he will kick overload after about 10 seconds.

I operate a AC service company and know about the problem with the starting load. This load is often double the regular AMP draw which is about 14 A - including the fan. 
I installed a hard-start to ease the compressor start. Of course, EVERYTHING else is switched off including the converter (I installed an additional switch for the converter).
I also have a 2 second time delay installed to have the fan start up after the compressor (the blue wire for low speed fan on the Carrier Air V).
With other words, when the AC starts there is nothing else hocked up but the compressor.

The unit is working fine on shore power.

Do I have a bad generator? 
Do you have the same problem with your Yamaha EF2400iS Generator?

We're new in the RV-hobby and need your experience and help!

Y'ALL take care - have a great day - Walter and Dianne.


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## KTMRacer (Jun 28, 2010)

Running a 13500 A/C off a 2000-2400 watt generator is hit and miss. first issue is getting it started, as your seeing. Altitude can have a big effect, you don't mention where your live, what is your altitude?

I have a honda 2000 watt generator running a coleman Mach III 13,500 BTU A/C on my 295RE. From the factory, the OEM A/C did NOT have a hard start cap and the A/C would only start if I had eco mode off. After installing a supco 6 hard start cap, it starts and runs the A/C even in eco mode and with a few other low draw loads on at 1000ft. Haven't tried it at higher altitude yet. However, it is running pretty much max current for the Generator, 13.5A which is the max continous for the honda.

Do a search on the forum or on the rvnet forum, seems like there are other posts from folks with the yami that are also having trouble, especially combined with the carrier AC units.


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## MJRey (Jan 21, 2005)

The same topic came up a few weeks ago and there was a fairly simple solution.

http://www.outbackers.com/forums/index.php?showtopic=30631&view=&hl=yamaha%202400&fromsearch=1


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## Chuggs (Jun 8, 2010)

Opps...disregard the following --- I overlooked the fact that you had a switch to turn off your converter









We've only had our Camper a short while...and I don't have any experience getting a/c units to run off the Generators...but while I was re-doing some battery cables on the camper --- I thought ---

The battery cables on the camper are 6 AWG. That's a 50-amp load rated wire...why so much, I wondered. The camper doesn't have any 50 amp circuits that I know of...then I remembered the converter is 12 v x 50 amp.

I would imagine...you could be trying to start your a/c and recharge your battery at the same time. I you haven't been on shore power for a while...chances are the battery isn't topped up...so when you connect the generator, the converter starts recharging the battery. Then you try to add another load by turning on the A/C and even with all the hard start capacitors in the world...there's still a load on that generator it cannot handle. I don't know how many 110v amps are pulled off the converter...but you'd have to add that to what your a/c unit is trying to pull.

You might need to power up the generator and let it recharge your battery for a while...before trying the a/c --- That's IF you haven't tried that already.

We'll probably try to get something like the EU3000Is when it comes time for a Generator add-on. Hopefully, it won't be as big a challenge to run the a/c. After all --- a/c in Florida is almost a necessity.


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## santurinos (Aug 1, 2010)

MJRey said:


> The same topic came up a few weeks ago and there was a fairly simple solution.
> 
> http://www.outbackers.com/forums/index.php?showtopic=30631&view=&hl=yamaha%202400&fromsearch=1


SURE, Ive read this post like the other on (all?) the forums...
YES, as I mentioned in my post, I already installed the hard start (SPP6), I have about 10 of them in my service van...
I disconnected everything except the compressor. I even temporarily disconnected the AC fan motor to see whether the compressor would start - no success!


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## CamperAndy (Aug 26, 2004)

Did you turn the fridge from Auto to Gas only operation?

If all AC loads are truly off then you should be able to but I have a few questions.

What altitude are you at? You loose 4% of generator performance for every 1000 feet in elevation.

Was the generator warmed up? Leave the converter on or fridge in auto for 5 minutes to warm up the generator then isolate all loads.

Did you try with the ECO throttle turned off?

Do you have the ability to start the fan and compressor at different times with your thermostat?


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## santurinos (Aug 1, 2010)

YES, I already installed the hard start (SPP6), I have about 10 of them in my service van...
I turned all the circuit breakers off except the main and the AC breaker.
We live at 587 feet above sea level in South West Georgia, altitude is not a problem here.

I installed an additional switch for the converter (12V DC - 50Amps). The converter takes power from the 120V line to convert it to 12V DC. This 12V supply is used to charge the batteries and other circuits like water pump, lights and so on. You actually never know how much Amps he draws at the 120 V supply. It depends on the charge of the batteries. I measured the converter intake this morning, he took 2.84 Amps = about 280 watt.

I disconnected everything except the compressor. I even temporarily disconnected the AC fan motor for about 30 seconds, just to see whether the compressor would start (without the fan taking power from the generator) - no success!
I am able to choose the starting time for fan after the compressor is rev up (2 to 30sec.). The timer activates a conventional fan relay after the preset time, this will start the fan.

Before starting the AC, I measure 0.04A at 120V with running generator (phantom amps).

Hooked up on shore power, the AC takes about 35A by start up and then 9.8A running at about 80ºF ambient. Just for your info, with lower temperatures in the morning, the AC will start up normally with my EF2400iS Generator, including the fan on low cool.

Afternoon with temperatures above 90º F, there is where the problems with the generator start on. FYI - this generator does not have a ECO throttle. 
Today afternoon it's about 90º F. My generator is ON, everything is disconnected. While starting the AC on low incl. fan, I measure 33.6A on start up. After about 10sec. The overload on the generator disconnects the power.
I restart the generator after about 5 min. I disconnect the fan for the next attempt.
The clamp meter measures 29.8A, the compressor starts up. I connect the fan - the AC is running this time, taking first 9.6A, then gradually increases to 12.1A. 
It is a hit and miss situation. On my second try, it will not work again&#8230;

There are two options available:
a: replace the capillary tubes with a TXV (thermal expansion valve). This will reduce the power consumption at start up and will increase the performance of the AC unit!
b: Replace the compressor with a smaller one, like a 10'000 Btu. This will of course reduce the capacity of the unit, but it will at least start and cool when we need it!

I will replace the capillary tubes first, then&#8230; well the compressor will go too.

Thank you for all the positive input.
Y'ALL take care - have a great day - Walter and Dianne.


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## CamperAndy (Aug 26, 2004)

Your Locked rotor start amps of over 30 is awful tough on a poor little 2400 and seems high for a 13500 BTU AC unit. I like your idea to modify the AC unit but I would ask you try one one test.

Can you record the voltage at the motor (cap) when you start and also at the shore power plug to see what losses you have. You could also have an issue with the wiring and have a poor connection. This can dramatically affect performance.


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## KTMRacer (Jun 28, 2010)

this certainly is unusual. Neighbor has an outback with a carrier 13500 unit. We recently put a supco 6 hard start cap on it and hooked it up to his honda 2000 watt generator. With a few interior lights on and the charger going (mostly charged battery) and the hond on eco start, he started the carrier several times. took about 3 seconds for the A/C to come on but once running, the generator wasn't even running at full throttle. I have similar experience with my honda 2000 with a coleman Mach III and supc cap on my outback. switching off eco mode results in a noticeable jump in RPM. Since the Yami s good for about 400 more watts, it's puzzling why your having trouble. I'd suspect something is definitely amiss with the carrier.


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## N7OQ (Jun 10, 2006)

I would load bank the generator and see if the trip circuit is set to light. Does it run the microwave OK? I think my unit is about 35amps locked rotor and I have no problem running mine was a 2800 watt kipor that runs 2500 watts continuous so it's not that much more than your genset. Also I have not installed my hard start yet.

If you install the thermal expansion please let me know how it works out, that is a mod I would do. Anyway my gut feeling keep telling me there is a problem with the genset.


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## OutbackPM (Sep 14, 2005)

Are you able to see if the Yamaha will run someone elses AC? Also see if another generator that has driven an AC will drive yours. That could give you a clue which part is not working right.

I side with CamperAndy in that you may have a bad connection that reduces your voltage and draws more current than needed. Good luck with you trouble shooting and let us know what you find.


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## santurinos (Aug 1, 2010)

First of all - thank you friends for all your help! Great to be with you.

_A/C and generator problem solved&#8230;_

The Yamaha EF2400iS Generator will easily run my Carrier Air V - Standard 13.500 BTU A/C and the fridge and the TV.

The problem is the start-up procedure.

First of all, everything has to be disconnected respectively switched off before starting the A/C.

I installed an additional switch for the converter (12V DC - 50Amps). The converter takes power from the 120V line to convert it to 12V DC. This 12V supply is used to charge the batteries and other circuits like water pump, lights and so on. You actually never know how much Amps he draws at the 120 V supply. It depends on the charge of the batteries, but it could take about 500 watts.

A hard start like the SPP6 is absolute necessary to ease the start up of the compressor.

With all of the above done, I could start the A/C sometimes, but many times the generator overload stopped it.

Upgrade you're A/C: 
I installed a fan delay circuit. When I turn the A/C ON (low cooling), the compressor starts immediately, but the fan comes on about 6 seconds after the compressor!
The fan motor takes about 10A for a short time at startup, together with the compressor about 35A. Depending on the weather (ambient temp) and the pressure at the high side of the compressor - this may trigger the overload.
Run the fan on High speed for about 3 min. before starting the A/C
Start the A/C on LOW-cool and let it running for about 3 min. then you can switch to Hi-cool.

I have started my upgraded A/C at up to 98º F outside temp without any problems.
My Carrier A/C takes only about 1250W to 1500W on at Low-cool respectively 1350W to 1550W at high cool. 
FYI: the low speed of the fan (fan only) is now controlled by the compressor start, it can not be turned on manually. The compressor will switch it on automatic. But the High speed is working normally. 
Of course, once the A/C is running, you may now turn the fridge and TV ON, everything that does not consume too much power (not the microwave)
PM me if you need more info about this upgrade.

Y'all take care, have a nice day - walter and dianne


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