Community Forums

twinboat · 08-16-2022, 12:30 PM

Red engine light ?

Do you have the oil level up to full ?

myfirstford · 08-16-2022, 07:55 PM

Your generator likely has a inverse/ time delay type shutdown. A minor overload, maybe 120%, is tolerated for a short period of time, say 180 secs, depending on the amount of overload. More overload = less time, less overload = more time.

Does your generator put out the correct voltage and frequency? Lower speed = frequency <60hz and a lower voltage. Both causes increased operating current. A longer than needed, or with a poor connection or smaller than required power cable will result in a an increased voltage drop and a lower voltage present at the AC unit. Lower voltage means that the operating current must increase to supply the same AC load. My Coleman install manual states that it must be wired with minimum 12 ga wiring from the generator to the AC. Additionally it states the voltage must be 115 +/- 10. As a troubleshooting aid, you could verify a proper voltage at the AC unit while running and before it shuts down. Lower voltage due to poor electrical could increase the run current.

A higher discharge head pressure results in the AC drawing more current which results in a higher operating current. as twinboat stated, make sure that the coils are clean and you do not have obstructions in the airflow. This increases pressures. Also, following a shutdown, give the AC refrigerant 5 min or so before attempting a restart to allow the high side to decrease by equalizing with the low side.

Measure the capacitance of your start and run capacitors with a digital multimeter with a capacitance scale and compare to manufactures data or the info that is usually printed on the caps. The AC specs would be best as some one may have already replaced them with something that was "close enough". These types of caps are prone to failure or just getting weak. Lower capacitance = increased current.

Good luck, your results may vary

emmmin · 08-17-2022, 05:53 PM

Quick update…I called both Dometic and Generac and was assured by both that the generator could run the AC. Generac recommended starting the generator first and then plugging in the power cord. Sounds simple. I am pretty sure I did that last time, but it did seem to make a difference. Tried running the AC with the generator again tonight (68 degrees out) and it ran fine for about two hours. I am going to try it again this weekend when it is supposed to be 90 degrees and humid. That should give me a better sense of whether or not it will work. If not, I looked into the Kill-A-Watt and will get one of those.

MesaMan · 08-21-2022, 10:39 AM

.
This lifelong Tech Geek just installed a new Micro-Air on my 13,500 BTU Coleman Mach A/C. I can see Stats on my Phone via Bluetooth; a fun detail.

A new Honda 2,200 Watt Genny ran the A/C faultlessly [after a stepped break-in period] in toasty, full Sun at >10,000' last Week outside Leadville CO. About any Genny loses >30% power at that elevation, and that didn't matter. The Genny was not heard to bog down, and my Progressive Industries 'Box' didn't shut down from Low Voltage dips. Another plus, and reassuring performance metric despite the Honda Spec being 1,800 Watts nominal output beyond 30 Minutes run time.

I lose the ~6 Amps load of the WFCO Charger by shutting it off [I'm on robust Solar]. The A/C 'Run' Amps averaged around 10 Amps 120 VAC after the Compressor spooled up. Also, the Micro-Air starts the A/C Fan alone for the first 6 Seconds. So, that bit of in-rush Current is moderated.

I'm a very happy, cooled Camper. I run the Dog-cooling A/C *very* little by choice; preferring high elevation Sites when Ma Nature permits...

.

bigb56 · 08-21-2022, 10:46 AM

If your converter is on and your house batteries are low that can draw quite a load.

twinboat · 08-21-2022, 12:34 PM

Quote:

Originally Posted by bigb56

If your converter is on and your house batteries are low that can draw quite a load.

My 55 amp IOTA drew 8 amps@ 120 volts at it's full 55 amp DC output.

More accurate then " quiet a few "

GIjoe · 08-21-2022, 03:01 PM

Quote:

Originally Posted by emmmin

I just bought a Generac 3300 Inverter Generator to run my 13500 BTU AC. Unfortunately, it cannot keep up and fails after only a few minutes. Since I cannot return the Generac, I am considering installing a Soft Start or something similar. I am a bit reluctant though as I feel like I just wasted $800 on a useless generator and don’t want to feel the same about the Soft Start which is $300. Any experience with one of these? Do they actually work as advertised? Is there any potential long term damage to the AC by using one?

I have a ETrailer 2000 surge 1600 running generator that runs my 13.5 AC just fine with the Soft Start module installed.

L Wagner · 08-21-2022, 03:13 PM

A lot of the generators on the market today from marketed as 3300 W but it’s not continuous, it’s only peak. It might be a 2800 watt continuous generator. Usually the only way to know is to read the tag off of the generator portion itself. On the inside of the unit sometimes you might have to take it apart. marketing people are very tricky!
And not always truthful. I just put soft starts on my three air conditioners today, I really haven’t had a chance to try them out yet but yes they are expensive. Good luck!

JMVAIL · 08-21-2022, 03:42 PM

Quote:

Originally Posted by emmmin

I just bought a Generac 3300 Inverter Generator to run my 13500 BTU AC. Unfortunately, it cannot keep up and fails after only a few minutes. Since I cannot return the Generac, I am considering installing a Soft Start or something similar. I am a bit reluctant though as I feel like I just wasted $800 on a useless generator and don’t want to feel the same about the Soft Start which is $300. Any experience with one of these? Do they actually work as advertised? Is there any potential long term damage to the AC by using one?

Don’t purchase from soft start AC they are a knock off from Microaire soft start the guy that is doing the soft start AC is ripping off Microaire he used to work for them he left taking information with him to start his own company he is a piece of work if you need a real reliable soft start go to MICROAIRE

wirenut1241 · 08-21-2022, 03:56 PM

Quote:

Originally Posted by emmmin

The generator claims a starting wattage of 3300 and running wattage of 2500 which according to what I have read should power the 13500 BTU AC.

Start up current can spike to 300 or more percent of running current. I have installed 2 soft starts on two different Rv's. Both start and run just fine on a 2000 watt generator. At times other loads may need to be shed ie; converter if batteries are taking a big charge or if you have a residential refer.
Both ac units were 15,000 btu.

sibe · 08-21-2022, 04:20 PM

Leave the Econo switch OFF

Start Genny let it warm up.. Turn on AC,, let it run 15-30 seconds on fan, then turn AC on Low..
that is
It should surge up and run fine...

A watt meter can help.. My 13.5 Coleman is new,, it pull 1150-1350 watts, depending on temp..
When my AC is OFF I have around 170-239 watts,, so 2 amp.. Fire AC amps go to 12.3- 13.7.. When my battery charge goes into equalize mode.. I see another 2 amps.. I was wonder why, Battery at full BUT charger happened to be in equalize mode..

I have run this AC on a 15 amp circuit and 125foot cord to my garage.. no issues,
I have a 3500 genny and a 2200 Ryobi.. both run itm the ryobi SCREAMS..but holds..

SO lots of advice, but let genny warm up, Economy switsh OFF.. run ac on fan and then go to low cold...
Good luck..

Allen K · 08-21-2022, 04:27 PM

Fuel issue?

Jim L. · 08-21-2022, 05:40 PM

Have a Dynamax REV, and plug into a 20A outlet at home. Have never been able to run the Dometic A/C, even though it’s on a 20A breaker. Always pops. 2 months ago I installed a softstart with the help of my son in law (who is very wiring savy…clutch), and the it works! Even with the fridge on electric. The main thing I noticed was no a/c power surge at start-up. It just eases its way to cooling. Completely worth the $340 I spent.

NewBlackDak · 08-21-2022, 05:45 PM

My generator would only run my AC if the hot water heater and fridge were set to gas, and the converter was turned off. As soon as the converter started in bulk charge mode it overloaded the generator, and kick it off. After I installed the soft start, I could leave the fridge and hot water on AC. Still no converter.