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Generac Air Cooled Generators Troubleshooting Questions, Answers, and Information About Air Cooled Guardian Generators

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Old January 22nd, 2009   #11
stnbenn
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Default Not sure if a hard start Cap. will help my situation

Today I got around to doing a governor set on my 044561 12kw propane fueled unit. Set the governor according to procedure, then set the freq. to 61.5 with full load speed adjustment screw, set voltage on regulator at 248. All adjustments done outside with no load on the generator.

Went to auto mode with all emergency circuits on, and generator lugged down somewhat when going online. (I got nervious as I have already lost a furnace blower relay and a Directv reciever from the brownout condition when the generator was trying to start everything). I quickly flipped off the heat pump breaker, and after allowing a few minutes of running, returned to utility power, generator then idled for a while and then shut down.

Later as a learning experiment I shut off all the circuits except the heat pump and went to auto mode. The generator lugged down a little (for maybe 5-10 seconds), and while lugged I measured about 165 volts (as best as I could determine) then the heat pump started and voltage came up to 245-247 and everything was OK. Note: when the 3 ton heat pump starts to run, the blower on the LP furnace starts as well (no lag between the compressor and blower motor starting). Am I asking too much of this 12 kw unit? I want the unit to start and run my heat pump, furnace blower motor, and 2 refrigerators when i'm in Florida or away from home during a utility power outage. Now I'm aware that if all are starting at the same time there is the almost an assurance that the load is too great and nothing really starts as it should.

I have reserved myself to using only the LP furnace (blower motor load) as my heat source during my absence, and maintaining the 2 refrigerators, and a 1 1/2 hp well water pump.

Do you think hard start capacitor's would help the starting current of the heat pump, and well pump?

My thoughts are that this generator is grossely under my power needs. I may either have to buy something that will handle just the necessary power loads, go to a whole house unit, or use nothing at all and let the homeowners insurance take care of the losses.

This unit has been a lot of work to get this far, no help from service reps in this area, (this site and members has been a wealth of help) and am tired of messing with it and replacing what equiptment it is burning up.

Your comments please.......Stan
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Old January 23rd, 2009   #12
johnc
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Stan: Why not use the propane furnace for heat instead of the heat pump? Motors and compressors pull at least 4x locked rotor amps (start amps) than normal running amps. Is your heat pump equipped with a time delay either by the manufacturer or a time delay built into your thermostat if it is an electronic type tstat. If the heat pump was running when power goes out it will try to restart too soon with generator power. Time delay relays are simple to install. Any mini second power outage locks out compressor for a time delay period. Serves two purposes, this allows all your other stuff to get powered up and settle into normal running amps and allows the pressures in the heat pump to equalize so compressor starts under no load condition. I don't think the hard start kit allows compressor to start at reduced amps. All the hard start kit does is throw the voltage out of phase slightly more than the run capacitor can do by itself.

Last edited by SkipD; February 21st, 2009 at 07:26 AM..
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Old January 23rd, 2009   #13
stnbenn
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John as far as I know, there is no time delay built in to either the heat pump circuitry or the T stat., however the time delay relay sounds like the best fix for the problem. I have several Potter & Broomfield plug in time delay relays around here but may not be 24 Volt. Will see what I have. We bought the heat pump about 5 years ago as a more economical heat source and it's saved us a bundle on fuel costs. It has been great especially when the propane price went out of sight the past year. My problem though is to be able to use it when utility power fails whether i'm at home or away.

I intend to use the propane furnace while i'm on vacation in Florida next month, as I don't trust the generator to run the heat pump and refrigerators without problems....Thanks much for the advice....Stan
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Old January 23rd, 2009   #14
stnbenn
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Default I stand corrected

After digging out the manual on the heat pump, it states that it does have a 30 second delay after a power outage. I don't think that is long enough to suit me though. I'm thinking about 2 things.

1. At present when the generator powers up the circuits after the utlity power fails and the heat pump was in operation, the heat pump compressor and the furnace blower motor start simultainously. I would like to first start the blower motor after a preset delay to allow the generator to be fully up to speed.

2. I would then like to start the heat pump compressor after the blower is up to speed as well.

Will have to study the schematic to see if the delay relays need to be in the 24 or 120vac side of the circuit.



I was thinking of installing two 24vac relays in the 24 v thermostat circuit. I do have a couple of 120v coil Allen Bradley 8 pin on delay relays on hand though. Will post the schematic for ideas. Stan

Last edited by stnbenn; January 23rd, 2009 at 02:58 PM..
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Old January 23rd, 2009   #15
johnc
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Stan: Your furnace wiring diagram probably isn't correct now if you have an add on heat pump. Some add on heat pumps had a somewhat large external control box mounted on or near the furnace so that the furnace(heat) and heat pump could never run at the same time. Some times just an outdoor thermostat was installed so when the outdoor temperature reached whatever the setpoint was, the heat pump locked out and the furnace took over as it got colder outside. Look up www.grainger, under their index, A/C, time delays, part # 4e234 (icm203). delay on break. On the heat pump find the compressor contactor. Should be a 24v coil, break either 24v coil wire with the relay. Set 4 to 5 mins. With your AB relays, you could wire the coil parallel to the main power, if the relays contacts will handle your motor amps, break the neutral motor wire. I would set the time delay to only a few seconds. Not exactly sure how the AB time delays work. They almost would have to be a delay on make. I would be hesitant to try to delay the 24v fan circuit, not knowing if any changes have been made. Never know if you are going to get any type of a feed back voltage thru the tstat. Don't forget when the heat pump turns on the blower must be on, whereas when the gas furnace fires there is a warm up period before the blower turns on.

Last edited by SkipD; February 21st, 2009 at 07:28 AM..
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Old March 10th, 2009   #16
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Finally got some warm weather. I wanted to check air conditioner start up amps, with and without a "hard start kit" installed.

1. normal compressor start up amps. 45 A. for a split second then drop to normal running amps 10A.

2. compressor start up amps with hard start kit installed. 32A for a split second then drop to normal running amps 10A.

The previous 2 tests were conducted when the system pressures were equalized. For those who may not know, when an air conditioner system is running, there are 2 separate pressures under which the freon is moved thru the system. One is a hi pressure and the other is a low pressure. Once the system is running and then cycles off, it takes approx. 2 minutes for the pressures to equalize. Thus when the air cond. starts again we want it start under no load conditions ( pressures equalized). Consider when the utility power goes off, and your air cond. is running, the generator fires up in approx. 20 seconds and switches power. Now your air cond. is going to restart with unequalized pressures.

Test 3.. Ran air cond. then shut off unit for 25 seconds and then restarted air cond. No hard start kit installed. 65Amps initial split second, then dropped to 45 Amps (standard start up amps) for a split second, then dropped to normal 10 Amps running.

So what we had was an additional 20 amp draw for a fraction of a second because the compressor was trying to start too soon.

Does this have an adverse effect on the generator? Hopefully someone who knows generators well can inform us.
Personally i prefer using a time delay relay to lock out the air cond. for a few minutes thus allowing it start under a "no load condition". Not only is this helpful for the generator load but even when your electric blinks for only a few seconds, your air conditioner is automatically locked off for a time delay period. A whole lot easier on your compressor life.
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Old March 11th, 2009   #17
Ira
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My thermostat delays restarting the A/C for five minutes following the power being restored (whether power is restored using the generator or POCO).
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Old March 11th, 2009   #18
stnbenn
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Ira, what brand and model thermostat are you using? Sounds like a great idea to have that delay feature built in......Stan
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Old March 12th, 2009   #19
Ira
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Quote:
Originally Posted by stnbenn View Post
Ira, what brand and model thermostat are you using? Sounds like a great idea to have that delay feature built in......Stan
It's a really old (almost 20 years?) thermostat that I put in when I built my house. It's a Honeywell MS3000 seven day programmable thermostat. The manual calls the feature "compressor protection". I googled the phrase along with "thermostat", and it looks like some current Honeywell thermostats have the same feature. Other manufacturers may offer the same feature under a different name.
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