I have a Generac QuietPac 40 LP which has worked fine since 2006. During a cross country trip last fall the ATS would take longer each startup to energize until finally it would not energize. After sitting all winter the ATS works fine now until the AC kicks on then the ATS kicks out for about 5-10 sec the kicks back on and runs fine. Should I replace the ATS or could it be something with the generator. Any thoughts would be appreciated.
AC Kicks Out Generator ATS
- Thread starter woodcreat
- Start date
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Larry N.
Well-known member
It sounds to me as if it could either be the ATS or it could be low voltage or max current from the generator. Monitoring the generator output voltage as the problem occurs might help identify where the problem is. I'm sure others will chip in here, too, with other thoughts, but you'll at least need to know about what that voltage does.
Gary RV_Wizard
Site Team
The ATS depends on generator voltage to determine whether to engage or not. If it falls below a certain threshold voltage, the ATS decides the genset is not active and it disconnects. It's conceivable the ATS is making a mistake, but far more likely that the generator voltage has actually fallen below the critical value. My bet is that the compressor start-up surge is overloading the genset momentarily and it ceases to put out power, so the ATS disengages. Then the genset rests and begins producing power, causing the ATS to resume generator mode.
The a/c compressor does what is known as a "hard start", consuming a huge amount of power for a second or so to get going. A compressor in poor working condition will be even harder to get going. Some RV a/c units have a "hard start capacitor" to give it a power boost for starting, and these are available as an add-on for those that do not. Your report that it has become progressively harder to get the ac/ started suggests that the capacitor on yours is dying or the compressor itself is getting weak. My first step would be to replace or add the capacitor on yours.
The a/c compressor does what is known as a "hard start", consuming a huge amount of power for a second or so to get going. A compressor in poor working condition will be even harder to get going. Some RV a/c units have a "hard start capacitor" to give it a power boost for starting, and these are available as an add-on for those that do not. Your report that it has become progressively harder to get the ac/ started suggests that the capacitor on yours is dying or the compressor itself is getting weak. My first step would be to replace or add the capacitor on yours.
Gary and Larry, thanks for your thoughts. The low voltage makes sense. I have a voltage monitor and it doesn't indicate excessive low voltage on AC startup but the drop may be too quick for the monitor. Going back to the trip last fall the ATS would take longer each startup without the AC involved until it wouldn't engage at all.
Gary RV_Wizard
Site Team
My apologies - I misunderstood. I thought it was the a/c that took longer to start up each time, but after re-reading I see I was flat wrong. That makes it seem more like the ATS than the a/c. In any case, the ATS relays are still voltage sensitive and the a/c start load may be dropping it enough that a weak relay is disengaging.
Have you checked the quality of the wire connections at the ATS. A loose wire or poor connection could exacerbate it enough to act flaky.
Is this a 30A ATS? Not all that expensive to replace if in doubt.
Have you checked the quality of the wire connections at the ATS. A loose wire or poor connection could exacerbate it enough to act flaky.
Is this a 30A ATS? Not all that expensive to replace if in doubt.
