winnebago a/c with heat pump shuts down generator

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UNCJIMMY

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Feb 5, 2019
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Ohio
During a recent test of the generator, starts fine, runs for some time.  Then after turning on the A/C unit/heat pump the generator shuts down immediately.  I'm guessing this problem is with the A/C unit shorting the A/C voltage thus shutting down the generator.  Any others out there experience a similar event.
Thanks,
Jim

edit by staff - changed message icon to topic solved
 

UNCJIMMY

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Ohio
John Canfield said:
Make, year model? Diesel or propane gen set? Please put your RV details in your signature (click on Profile in the menu.)
Not mine yet :) .  Propane generator, Mercedes-Benz gas engine, Winneabago ERA 170x.  Thanks !
 

ennored

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This right?

2,500-watt Cummins Onan? MicroQuiet? LP generator

13,500 BTU low-profile high-efficiency roof air conditioner


A 13,500 BTU AC, combined with a couple other loads (converter, fridge, other 120 devices) is probably more than 2500 watts.

Also note that 2500 watts is under standard/ideal conditions. Output drops as elevation goes up for example.
 

Lou Schneider

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Yes, air conditioners have a large starting surge and a 2500 watt generator is marginal.  It was probably selected due to space constraints.

Make sure nothing else was drawing power while you were trying to start the A/C.  Refrigerator in Gas mode (300-400 watts), water heater off (up to 1500 watts if the electric element is on) and so forth.
 

UNCJIMMY

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Ohio
"A 13,500 BTU AC, combined with a couple other loads (converter, fridge, other 120 devices) is probably more than 2500 watts."

Lou Schneider said:
Yes, air conditioners have a large starting surge and a 2500 watt generator is marginal.  It was probably selected due to space constraints.

Make sure nothing else was drawing power while you were trying to start the A/C.  Refrigerator in Gas mode (300-400 watts), water heater off (up to 1500 watts if the electric element is on) and so forth.

Well, good advice ennord and Lou thanks, only item on was a few over head lights, fridge was off and so was water heater.  I thought it would pull 13.3 amps according to documentation.  But as you both suggest I researched the startup/run wattage to be for 13,500 btu RV air conditioner: 2750: 1250:  So 2750/120 is 23 amps, which is more than that 2500 generator can supply.  Darn, darn, darn.  But thanks.
 

John Canfield

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Another point is your propane generator would burn through the propane in your small propane tank very quickly. The Onan diesel gen sets are on the other hand are very fuel efficient. I have a 7.5Kw Onan QuietDiesel which burns on the average about 1/3rd gallon an hour with my usual load of air conditioning, water heater, TV, etc., etc. I've run for four or five days at a time on generator with plenty of fuel left to travel.
 

Mile High

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I have heard that is pretty normal for that coach.  I don't think the gen was sized to run the AC.  Some have opted to surrender the gen for space as a result.
 

IBTripping

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You might consider getting a soft start adapter which lessens the surge when your air conditioner compressor kicks in on your roof top unit. After installing, your generator will easily be able to power your ac. Here's an example of one: https://www.microair.net/products/easystart-364-3-ton-single-phase-soft-starter-for-air-conditioners?variant=30176048267

A much less expensive option (about $10) is to swap the capacitor in your a/c unit with a Micro Air soft start capacitor. Here's a Youtube video on how to do it: https://www.youtube.com/watch?v=DsgRachoLEA

 

UNCJIMMY

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Ohio
John Canfield said:
Another point is your propane generator would burn through the propane in your small propane tank very quickly.

Good point, out of fuel in no time.  Thanks.


Mile High said:
I have heard that is pretty normal for that coach.  I don't think the gen was sized to run the AC. 

For sure.  Thanks.  I'll keep shopping.

IBTripping said:
You might consider getting a soft start adapter which lessens the surge when your air conditioner compressor kicks in on your roof top unit.
A much less expensive option (about $10) is to swap the capacitor in your a/c unit with a Micro Air soft start capacitor.

Great idea.  Sounds like it should be included in the original design. Thanks.
 
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