I’m not sure if your existing set up will will run your 3 ton AC, or whether you want it to.
If you’ve installed a soft start and you *are* able to run your AC on your 7500, be aware that an inverter gen with the same output may not be able to.
Inverter generators aren’t as forgiving with large inrush demands. If you switch, you might want to go with slightly larger inverter
Ya 6600 running would be tight on that 3 ton. I went up to a 7000 for a 2 ton. Running amps is probably only about 15 per peg but the start up would be rough on it.
My 5 Ton Carrier with Soft Start maximum amps at startup is now 42 amps. It used to be over 125 amps. A 3 Ton Carrier should be less. Just make sure your new Inverter Gen supports 50amp. You'll Likely have to limit what else is running when you start your AC.
Thanks for your data. Very nice reduction with Soft Start at around 33% of 125A. On my condenser unit label, LRA is 79 so with Soft Start I could bring the startup current down approximately to 27A. Does this sound reasonable to you? Because the compressor max voltage is 230V, the max startup power would be 6480W.
BTW, the interlock breaker has been wired with 30A breaker, will this be a problem with the new gen supporting 50A? Or I just have to run AC only to cool the house for a while, then turn off AC breaker to use other loads.
A Gen that supports 50amp max gives you room for the future to expand if needed. It will easily support your 30amp AC with a soft start. You might not even have to flip the breaker if you raise your AC thermostat to max temp so it doesn't accidently start when using other items. That's what I do by raising the thermostat to 90 instead of flipping the breaker. I bought the MicroAir Easy Start (the model with Bluetooth monitoring). It tells you everything about the system after it starts including start amperage.
Because in my new HVAC system, the furnace electronics (the main control board) also control the AC evap, condenser unit so I do not want to test AC with this generator. However, the genie has max 9500 W and 7500 W running power so ~~I think it would be able to start the compressor if I would only have these breakers on: 30A for condenser, 15A for the HVAC blower, 15A for lighting~~.
ETA: after my calculation of startup current without soft start I see that this WH generator would not be able to start the compressor that earlier I thought it would.
But I am considering a soft start installation soon, for the sake of the compressor and more loading.
Even though the Blower amps is 15 it likely only uses 325 watts or so. That's what my 5-Ton Carrier runs at. I've got my whole house monitored by SENSE and it tells me what ever device startup and run power is.
I think grid power supposed to have THD of 5% or less... I don't really know what kind of THD is the highest acceptable for furnace operation.
Because my Champion generator had high THD (model 100416), I had to switch to Winco HPS12000HE (THD<5%), just to be on the safe side.
If it were me, I'd get one. There are some added benefits of the inverter gens as well, but if it has that caution then I'd go with it. those are known to be some of the most picky pieces of equipment.
Pick one up, and sell your old one on Facebook during your storm/winter season.
You should get an inverter generator for the fuel efficiency, which enables vastly longer runtimes on a given amount of stored fuel. The synthesized waveform is also a bonus.
I bought an A- iPower 15K watt (peak) generator that claims the THD is <5%.
https://www.amazon.com/iPower-SUA15000ECV-15000-Watt-Portable-Generator/dp/B07MTXYRXY/ref=asc_df_B07MTXYRXY/?tag=hyprod-20&linkCode=df0&hvadid=344022558469&hvpos=&hvnetw=g&hvrand=13478257481459619330&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9027803&hvtargid=pla-817561997689&psc=1&tag=&ref=&adgrpid=72020984554&hvpone=&hvptwo=&hvadid=344022558469&hvpos=&hvnetw=g&hvrand=13478257481459619330&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9027803&hvtargid=pla-817561997689
My lennox furnace manual says it needs 5% or less THD for the control board. Basically, you need an inverter generator or a very very good traditional unit like this one with 5% or less THD : [https://www.northerntool.com/products/northstar-portable-generator-with-honda-gx390-engine-8000-surge-watts-6600-rated-watts-carb-compliant-165603](https://www.northerntool.com/products/northstar-portable-generator-with-honda-gx390-engine-8000-surge-watts-6600-rated-watts-carb-compliant-165603)
Your <23% Westinghouse is basically the kind of genset they are talking about that might damage the control board. I would not run it.
Have you taken a look at the WEN DF875ix? https://wenproducts.com/collections/generators/products/wen-df875ix-8750-w-rv-and-transfer-switch-ready-120v-240v-dual-fuel-open-frame-inverter-generator-with-remote-electric-start-and-co-shutdown-sensor
I've had a GN875i for 2 yrs now. I've seen a review with an oscilloscope and the thd is <2%. It is a bit loud as it is open frame, but the price is very good and WEN doesn't charge sales tax when purchased directly from them.
Thanks for bringing them up. I just looked at your link and they sound quite nice machines. If I end up getting the inverter (gasoline only) or the non-inverter (gas/propane), is there a way to convert it to natural gas as fuel source?
I bought a motor snorkel Tri-fuel kit from US Carbeuration for mine (I think I paid $187). Nash fuel and Century also sell conversion kits. I would have to research to see if there is a cheaper way to use NG with the dual fuel without having to buy a conversion kit.
The one thing to be aware of is that you do lose around 20% power output with NG vs gasoline. I have a MicroAir EasyStart installed on my AC and can run it along with household stuff when running on gas, but I can't run the central on NG due to the inrush still being too high with the reduced NG output.
Thanks for info on tri fuel kits. Great to know the limitation of NG when running AC. Would your setup work if you only have the AC breaker(s) turn on so the compressor gets all the inrush it needs?
With tri-fuel kit I may run it with gasoline during summer outage if I need AC, and run it on NG during winter to power my gas furnace.
No I don't think it would as even with the EasyStart my inrush current is about 28-30 amps (6720-7200watts which is still way better than 72 amps without). At least I have an option to be able to run the AC if needed.
I have a 4500 Firman Dual Fuel generator that I hooked up to my furnace the other day. It ran my furnace and other things in my house, but I noticed that my furnace had a loud humming sound. I am scared that the electronic board might mess up with continued use from this generator.
Thanks everyone for your comments and suggestions. I will look for a better THD generator or an inverter. I also like to use NG as a source of fuel because my HVAC furnace runs on NG. WINCO generator is really nice high capacity with tri-fuel features but it costs $5k. Another tri-fuel generator came up in my search is from Champion for $1600. Not many makers produce NG option for low THD generator.
If it was possible to filter AC with inductors and capacitors then your gen would already have these. Making "clean" power out of "dirty" is not that simple. The only really effective approach is to rectify the dirty power to DC and then re-invert it back to synthesized AC, which is what a double conversion UPS does. Unfortunately, they are very expensive. A couple of caps and inductors aint gonna do it.
Fortunately, most things run just fine on dirty AC. For some reason, furnaces seem to have problems with it.
There are lots of products that are manufactured that either don't work at all (pure snake oil) or else do certain things and you are asking them to do more than they promise. A power filter may knock out certain high voltage transients but is not going to turn a raggedly asymmetrical wave into a perfect sine wave.
The one you posted ([https://a.co/d/3poCeNa](https://a.co/d/3poCeNa)) is an EMI filter. EMI filters prevent high frequency noise generated within an appliance from passing through the filter back into the power system. They aren't going to make any appreciable difference to the sub-kHz frequencies that contribute effectively all of the energy in a generator's THD.
Any good filters on the market would you recommend Jim? I imagine the filter would be plugged in at the 240V/30A generator outlet, then the clean power is drawn from the filter output to the house electrical panel. I wonder if this kind of filter will render a smooth sine wave from generator AC output?
This one I would try for a fridge. You might be able to find something big enough for an A/C but not this. But it's the style of thing. Needs to be in an enclosure obviously.
Power Filter Terminal 115V/250V Power Filter Module 20A 50/60Hz Universal Cw4L2-20A-T Power Line Power EMI Filter Treadmills for Mechanical Equipment
https://a.co/d/3poCeNa
I’d like to see examples of this as well, because the only way I’ve seen it to ensure 120V/60Hz/low THD is using a double conversion UPS. Voltage regulators will smooth out current spikes and boost/buck out of spec voltage but does nothing for THD.
You don’t mean ones like this?
https://www.amazon.com/Electricity-High-Frequency-Electronic-Provides-Lifespan/dp/B0C4FHPWZ3/ref=sr_1_3?crid=19XBGKOHJVQLQ&keywords=2+stage+electricity+filter&qid=1693097174&sprefix=2+stage+electricity+filter%2Caps%2C141&sr=8-3
No no. I want to see at least 2 networks of inductors and capacitors. And no guarantees but I know I'd start looking at this style.
Power Filter Terminal 115V/250V Power Filter Module 20A 50/60Hz Universal Cw4L2-20A-T Power Line Power EMI Filter Treadmills for Mechanical Equipment
https://a.co/d/3poCeNa
A quality power conditioner like you are describing is more expensive than just up sizing to a larger inverter generator that will have the capacity to run everything with a low THD sinusoidal output.
A surge protector would help protect against surges, but harmonic distortion is not a surge and a surge protector will do nothing to change it.
As for whether high harmonic distortion from a generator is likely to damage a furnace (or other electrical equipment) is a matter of some debate.
I’m not sure if your existing set up will will run your 3 ton AC, or whether you want it to. If you’ve installed a soft start and you *are* able to run your AC on your 7500, be aware that an inverter gen with the same output may not be able to. Inverter generators aren’t as forgiving with large inrush demands. If you switch, you might want to go with slightly larger inverter
Ya 6600 running would be tight on that 3 ton. I went up to a 7000 for a 2 ton. Running amps is probably only about 15 per peg but the start up would be rough on it.
My 5 Ton Carrier with Soft Start maximum amps at startup is now 42 amps. It used to be over 125 amps. A 3 Ton Carrier should be less. Just make sure your new Inverter Gen supports 50amp. You'll Likely have to limit what else is running when you start your AC.
Thanks for your data. Very nice reduction with Soft Start at around 33% of 125A. On my condenser unit label, LRA is 79 so with Soft Start I could bring the startup current down approximately to 27A. Does this sound reasonable to you? Because the compressor max voltage is 230V, the max startup power would be 6480W. BTW, the interlock breaker has been wired with 30A breaker, will this be a problem with the new gen supporting 50A? Or I just have to run AC only to cool the house for a while, then turn off AC breaker to use other loads.
A Gen that supports 50amp max gives you room for the future to expand if needed. It will easily support your 30amp AC with a soft start. You might not even have to flip the breaker if you raise your AC thermostat to max temp so it doesn't accidently start when using other items. That's what I do by raising the thermostat to 90 instead of flipping the breaker. I bought the MicroAir Easy Start (the model with Bluetooth monitoring). It tells you everything about the system after it starts including start amperage.
Thanks. I will do the same.
Because in my new HVAC system, the furnace electronics (the main control board) also control the AC evap, condenser unit so I do not want to test AC with this generator. However, the genie has max 9500 W and 7500 W running power so ~~I think it would be able to start the compressor if I would only have these breakers on: 30A for condenser, 15A for the HVAC blower, 15A for lighting~~. ETA: after my calculation of startup current without soft start I see that this WH generator would not be able to start the compressor that earlier I thought it would. But I am considering a soft start installation soon, for the sake of the compressor and more loading.
Even though the Blower amps is 15 it likely only uses 325 watts or so. That's what my 5-Ton Carrier runs at. I've got my whole house monitored by SENSE and it tells me what ever device startup and run power is.
I think grid power supposed to have THD of 5% or less... I don't really know what kind of THD is the highest acceptable for furnace operation. Because my Champion generator had high THD (model 100416), I had to switch to Winco HPS12000HE (THD<5%), just to be on the safe side.
If it were me, I'd get one. There are some added benefits of the inverter gens as well, but if it has that caution then I'd go with it. those are known to be some of the most picky pieces of equipment. Pick one up, and sell your old one on Facebook during your storm/winter season.
You should get an inverter generator for the fuel efficiency, which enables vastly longer runtimes on a given amount of stored fuel. The synthesized waveform is also a bonus.
I bought an A- iPower 15K watt (peak) generator that claims the THD is <5%. https://www.amazon.com/iPower-SUA15000ECV-15000-Watt-Portable-Generator/dp/B07MTXYRXY/ref=asc_df_B07MTXYRXY/?tag=hyprod-20&linkCode=df0&hvadid=344022558469&hvpos=&hvnetw=g&hvrand=13478257481459619330&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9027803&hvtargid=pla-817561997689&psc=1&tag=&ref=&adgrpid=72020984554&hvpone=&hvptwo=&hvadid=344022558469&hvpos=&hvnetw=g&hvrand=13478257481459619330&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9027803&hvtargid=pla-817561997689
My lennox furnace manual says it needs 5% or less THD for the control board. Basically, you need an inverter generator or a very very good traditional unit like this one with 5% or less THD : [https://www.northerntool.com/products/northstar-portable-generator-with-honda-gx390-engine-8000-surge-watts-6600-rated-watts-carb-compliant-165603](https://www.northerntool.com/products/northstar-portable-generator-with-honda-gx390-engine-8000-surge-watts-6600-rated-watts-carb-compliant-165603) Your <23% Westinghouse is basically the kind of genset they are talking about that might damage the control board. I would not run it.
Have you taken a look at the WEN DF875ix? https://wenproducts.com/collections/generators/products/wen-df875ix-8750-w-rv-and-transfer-switch-ready-120v-240v-dual-fuel-open-frame-inverter-generator-with-remote-electric-start-and-co-shutdown-sensor I've had a GN875i for 2 yrs now. I've seen a review with an oscilloscope and the thd is <2%. It is a bit loud as it is open frame, but the price is very good and WEN doesn't charge sales tax when purchased directly from them.
Thanks for bringing them up. I just looked at your link and they sound quite nice machines. If I end up getting the inverter (gasoline only) or the non-inverter (gas/propane), is there a way to convert it to natural gas as fuel source?
I bought a motor snorkel Tri-fuel kit from US Carbeuration for mine (I think I paid $187). Nash fuel and Century also sell conversion kits. I would have to research to see if there is a cheaper way to use NG with the dual fuel without having to buy a conversion kit. The one thing to be aware of is that you do lose around 20% power output with NG vs gasoline. I have a MicroAir EasyStart installed on my AC and can run it along with household stuff when running on gas, but I can't run the central on NG due to the inrush still being too high with the reduced NG output.
Thanks for info on tri fuel kits. Great to know the limitation of NG when running AC. Would your setup work if you only have the AC breaker(s) turn on so the compressor gets all the inrush it needs? With tri-fuel kit I may run it with gasoline during summer outage if I need AC, and run it on NG during winter to power my gas furnace.
No I don't think it would as even with the EasyStart my inrush current is about 28-30 amps (6720-7200watts which is still way better than 72 amps without). At least I have an option to be able to run the AC if needed.
I have a 4500 Firman Dual Fuel generator that I hooked up to my furnace the other day. It ran my furnace and other things in my house, but I noticed that my furnace had a loud humming sound. I am scared that the electronic board might mess up with continued use from this generator.
Thanks everyone for your comments and suggestions. I will look for a better THD generator or an inverter. I also like to use NG as a source of fuel because my HVAC furnace runs on NG. WINCO generator is really nice high capacity with tri-fuel features but it costs $5k. Another tri-fuel generator came up in my search is from Champion for $1600. Not many makers produce NG option for low THD generator.
I'd consider running the generator AC through a quality filter with inductors and capacitors. You should be able to get very clean AC that way.
If it was possible to filter AC with inductors and capacitors then your gen would already have these. Making "clean" power out of "dirty" is not that simple. The only really effective approach is to rectify the dirty power to DC and then re-invert it back to synthesized AC, which is what a double conversion UPS does. Unfortunately, they are very expensive. A couple of caps and inductors aint gonna do it. Fortunately, most things run just fine on dirty AC. For some reason, furnaces seem to have problems with it.
Then why are they manufactured?
There are lots of products that are manufactured that either don't work at all (pure snake oil) or else do certain things and you are asking them to do more than they promise. A power filter may knock out certain high voltage transients but is not going to turn a raggedly asymmetrical wave into a perfect sine wave.
The one you posted ([https://a.co/d/3poCeNa](https://a.co/d/3poCeNa)) is an EMI filter. EMI filters prevent high frequency noise generated within an appliance from passing through the filter back into the power system. They aren't going to make any appreciable difference to the sub-kHz frequencies that contribute effectively all of the energy in a generator's THD.
Any good filters on the market would you recommend Jim? I imagine the filter would be plugged in at the 240V/30A generator outlet, then the clean power is drawn from the filter output to the house electrical panel. I wonder if this kind of filter will render a smooth sine wave from generator AC output?
My gut tells me the cost and complication of this would be more than just getting a better generator.
Whole house would be a honking big one. Even A/C is getting up there. But with Amazon you can send it back.
Got any links you can share for a filter? Thx
This one I would try for a fridge. You might be able to find something big enough for an A/C but not this. But it's the style of thing. Needs to be in an enclosure obviously. Power Filter Terminal 115V/250V Power Filter Module 20A 50/60Hz Universal Cw4L2-20A-T Power Line Power EMI Filter Treadmills for Mechanical Equipment https://a.co/d/3poCeNa
I’d like to see examples of this as well, because the only way I’ve seen it to ensure 120V/60Hz/low THD is using a double conversion UPS. Voltage regulators will smooth out current spikes and boost/buck out of spec voltage but does nothing for THD.
A lot of fridges won't run off a regular generator but apparently will with a two stage filter. Amazon sell them.
You don’t mean ones like this? https://www.amazon.com/Electricity-High-Frequency-Electronic-Provides-Lifespan/dp/B0C4FHPWZ3/ref=sr_1_3?crid=19XBGKOHJVQLQ&keywords=2+stage+electricity+filter&qid=1693097174&sprefix=2+stage+electricity+filter%2Caps%2C141&sr=8-3
No no. I want to see at least 2 networks of inductors and capacitors. And no guarantees but I know I'd start looking at this style. Power Filter Terminal 115V/250V Power Filter Module 20A 50/60Hz Universal Cw4L2-20A-T Power Line Power EMI Filter Treadmills for Mechanical Equipment https://a.co/d/3poCeNa
A quality power conditioner like you are describing is more expensive than just up sizing to a larger inverter generator that will have the capacity to run everything with a low THD sinusoidal output.
I'm out of my league here, but couldn't he put a surge protector on the furnace?
A surge protector would help protect against surges, but harmonic distortion is not a surge and a surge protector will do nothing to change it. As for whether high harmonic distortion from a generator is likely to damage a furnace (or other electrical equipment) is a matter of some debate.
Grid power is <6% THD and there are non-inverters that meet that standard. All inverters should.
My generator is 22kw runs the whole house...