Yamaha EF2400iS Generator don’t run 13,500 AC

[santurinos]

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.

[450Donn]

Did you turn off the water heater too? How about the refer?
What is the full load amp rating of the 2400I ?
See I believe that some not all AC units can be run from the 2400. I have a Yamaha YG280I and it will start and run my 15K AC unit. But I also turn the refer and water heater to gas only. But even with all that my generator knows when the AC compressor kicks in.

[bigskymt]

Can you put an 'amp-clamp' on the line and see what the unit is actually drawing?

[santurinos]

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…

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… well the compressor will go too.

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

[450Donn]

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.

And therein lies your problem. To get 35 amps you will need a really big generator.

[santurinos]

Originally Posted by 450Donn

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.

And therein lies your problem. To get 35 amps you will need a really big generator.

Dear Donn,
Again, thank you for your contribution!
Looks like I found a new friend.
I am able to solve this problem (hopefully)
But I am upset with that many people reporting that this generator works like champ on a 13'500 btu RV ac unit!!!!!!!!!!!!


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…

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… well the compressor will go too.

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

[450Donn]

Just thought of something. Are you running the generator on Econo mode? You absolutely MUST run the generator on full power mode or what ever it might be called when trying to start and run an AC unit.

[RVhauler]

If you are not attempting to start in the wrong mode then would be suspect of the generator overload. Would not modify the AC. Have never seen a 13K AC equipped with hard start kit that wouldn't run. Cheaper to try another breaker first than any of the other methods

[santurinos]

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

[Ray,IN]

Santurinos, What you have experienced is why, after studying the specifications of each genset brand suitable for RVing, and my needs; I decided upon purchasing a RV's choice for Portable Power - Boliy USA, Home of the Boliy Generator
That was in June 08, I am still satisfied I made a good decision today. I'd like to have a new electric-start model, but at this rate my 08 pull-start will out-live me.

[santurinos]

Originally Posted by Ray,IN

I decided upon purchasing a RV's choice for Portable Power - Boliy USA, Home of the Boliy Generator
That was in June 08, I am still satisfied I made a good decision today. I'd like to have a new electric-start model, but at this rate my 08 pull-start will out-live me.

Hello Ray,
YES - I had a hard time to decide which one of the two to buy...
I was a bit worry about the service and spare parts with the Boliy, so I decided literally in the last second to get the Yamaha.
I hope the Boliy will get popular in the RV community and bring a new choice in this market.
I love my super-quiet Yamaha, starting every time by the first pull!
I love the light weight (74lb) - easy to carry together with Dianne. But I would like to have a bit more power available on my Yamaha.

Have a nice day - walter and dianne.

[Blackcvpi]

I have a 2400 yamaha and it starts and runs the 13500 duotherm on my unit just fine. When its real hot out it has a little trouble restarting but it never overloads it. I do plan to add a hot start to help reduce the strain.