fgamache

My 11kw unit is connected via an AGS that I can program to run a scheduled exercise, including going with load (I am off-grid), instead of the 10min biweekly that Generac is setup to exercise at low speed...

Curious to hear opinions on best duration, frequency and load/no load to keep my unit young, vibrant and happy?
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BillM
I live in a cold climate (Wisconsin) and I have a 22kw generator (NG) that I allow to excercise weekly for it's 5 minutes, but I also run it for 30-45 minutes once every 90 days because I'm worried about moisture in the oil.  I also do full load tests a couple times a year, maybe 3 times.  My generator is 6 years old.  I've had a cumulative 90 seconds of utility electrical failure so I haven't really had the opportunity to enjoy homemade electrons.  I am a strong believer in load tests.  
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Cobranut
I strongly believe that less frequent, but longer duration test, underl load if possible, are better for longevity than weekly short runs.
Short runs cause condensation buildup in the oil, and cold starts cause a majority of wear in an engine.
I run my 30kW diesel only about every three months, but it gets a full 30 minutes under significant load each time.
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Birken Vogt
Do you have really great solar such that it never runs 6 months out of the year?

If not, the regular battery charging runs will be all the exercise it needs.
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78buckshot
I agree with Cobranut as far as fewer starts and longer runs, one thing to keep in mind is not only the engine but the generator head needs regular runs to keep the slip rings from oxidizing and to keep the rotor and stator windings dry. If you are in a climate that see's damp conditions and/or condensation forming with temperature swings then running is the design to keep the components dry.
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kf3cw
After seeing milky oil on a 1 year old 22kw Generac running on natural gas, I called Generac . The lady in customer service told me after I had changed the oil and filter to run the generator UNDER LOAD by merely pulling down the switch on the external of the transfer panel and that would automatically run the generator under load. She suggested running it for about an hour ONCE A MONTH. I’ve not had any water in my oil ever since following this procedure now for over a year.  My only concern is how hard is this sudden jolt on all of the appliances running and am I taking a chance of damaging the AC , dehumidifiers, refrigerator, etc. by doing this ?
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78buckshot
In situations where I know that I am going to shut down the house I turn off the individual branch breakers one at a time and then kill the main. When I re-energize either with utility or generator I then turn on the branch breakers one at a time, my thought here is that there will be less arc or no arc at the main breaker and each appliance has a chance to come to a stop before re-energizing. This is not the case when I am testing the generator and transfer switch after I complete the maintenance on the generator, in that situation I simply pull the N1 or N2 fuse and observe the system in operation. I have seen air conditioning compressors run in reverse when utility power is restored due to the quick transfer, it's best to let the motors come to a stop before re-energizing but in real life while you are not home and the generator operates automatically in an outage you are at the mercy of the system design.
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Cobranut
78buckshot wrote:
In situations where I know that I am going to shut down the house I turn off the individual branch breakers one at a time and then kill the main. When I re-energize either with utility or generator I then turn on the branch breakers one at a time, my thought here is that there will be less arc or no arc at the main breaker and each appliance has a chance to come to a stop before re-energizing. This is not the case when I am testing the generator and transfer switch after I complete the maintenance on the generator, in that situation I simply pull the N1 or N2 fuse and observe the system in operation. I have seen air conditioning compressors run in reverse when utility power is restored due to the quick transfer, it's best to let the motors come to a stop before re-energizing but in real life while you are not home and the generator operates automatically in an outage you are at the mercy of the system design.


This is why I like the in-phase transfer capability of my Thomson transfer switch.
My A/C and other motors don't even notice the transfer.  It's especially nice when running an exercise, as there's no loss of power to the house during either transfer.
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murphy
The Hyper Engineering Sure Start documentation claims that it can detect a compressor running in reverse and shut it down.
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grsthegreat
i always hear about ac compressors running backwards after transfer, but im confused. both units i have owned had like a 5 minute delay after powering it down to equilize pressures. im not sure if the honeywell tstats did that or the controller at the ac unit. im not an ac man. i have only noticed this when messing with my ac unit.
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Cobranut

grsthegreat wrote:
i always hear about ac compressors running backwards after transfer, but im confused. both units i have owned had like a 5 minute delay after powering it down to equilize pressures. im not sure if the honeywell tstats did that or the controller at the ac unit. im not an ac man. i have only noticed this when messing with my ac unit.


Trouble is, the transfer happens quickly, and the thermostat doesn't reset.  When the phase shifts, the rotor sometimes momentarily stalls and reverses rotation.  Since it never actually used the start capacitor to give it a push in the right direction, it can reverse rotation.
This will stop cooling, and it will continue to run this way until manually shut down and restarted.
I'm not sure how long it would take to cause permanent damage, but since it won't be properly circulating oil through the system, I'm sure it would eventually cause premature wear, and eventually failure.

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grsthegreat
oh, so your saying this can happen when you transfer a generator load during a test when utility power is still on, not during an actual power failure situation?
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murphy
It can happen in either case.  In a power failure situation the utility power is on before the transfer back can occur.
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Birken Vogt
Brian Baughman or somebody from the company had come on here once and stated that a compressor running in reverse would soon trip the thermal protector and then when it reset itself, would start in the right direction.
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78buckshot
If the thermostat/s have battery back-up as most do then it won't know of a power outage, the 5 minute delay won't play a part.  Like Murphy said, the problem is when the utility comes back and the transfer is hot. You probably won't know the difference with an older ac due to them using reciprocating compressors - it will work in either direction. Most if not all newer residential stuff now use scroll compressors and will only move refrigerant when running in the correct direction. Yes, the hermetic compressors have a thermo-overload buried in the motor windings, when they trip the compressor stops until it cools and re-sets automatically. 
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grsthegreat
VERY INTERESTING.....i have a few Hyper Engineering sure starts in stock...i just may add one to my own ac compressor to be safe. ive only used them in the past for heat pumps....but they work fine for ac units as well. better safe than sorry.
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78buckshot
Yeh, as long as you get them at cost you might as well take advantage of it. They do make an incredible difference.
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Cobranut

Birken Vogt wrote:
Brian Baughman or somebody from the company had come on here once and stated that a compressor running in reverse would soon trip the thermal protector and then when it reset itself, would start in the right direction.

That's probably true, but only AFTER it has overheated.

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BillM
I bought a SureStart from my dealer, they are amazing at technical support and go the extra mile to make sure you are working.  Give them a call at 888-294-5537 and mention me.  Two more referrals and I get a sticker to put on my Generator.  They *price match so there's no reason to use anyone else.
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fgamache
Birken Vogt wrote:
Do you have really great solar such that it never runs 6 months out of the year?

If not, the regular battery charging runs will be all the exercise it needs.


That pretty much my situation: gen runs regularly Nov-Feb and then almost never the rest of the year...
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fgamache
Thanks for all the ideas and opinions : seems there is *some* consensus on longer/less frequent runs and under load as the best approach...
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