re: Who has an A/C soft start?

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now yall have me concerned with running a 5 ton unit with firman trifuel... maybe i should go bigger generator

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As others have said, you likely can run your HVAC on the smaller one with a soft starter. But you’ll probably be on the edge of what it can handle so any other moderate loads will stall it or trip the breaker on it. Your heavier loads are anything that use 240V (AC compressors, ovens, driers, cooktop, etc.) and the moderate loads on 120V will be appliances like a microwave, fridge, or vacuum cleaner.

If you’re willing to run your HVAC and some lights (LED) and maybe a tv, you should be okay. But if you’re already on the edge of that limit you’d have to be extremely aware of whatever else you’re using.

So, if you’re capable and willing to do that, rock on. If you have a kid (or multiple) who will plug something in and turn it on without paying attention to your directions, get a larger generator .

EDIT: just noticed you mentioned propane or gasoline - that thing will drain with a quickness if running your 5 ton. I probably wouldn’t do it without an NG line.

i have big propane tanks (100lb) and could last 2-3 days with them. i would only run the central air during the day and 2 fridges and a freezer. I will run window units at night in sleeping rooms

im going to test load all this once my micro air arrives

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Yes. Variable speed units are variable frequency drives. They already "soft start" when kicked on.

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i had the same question. I have two units that are VFD. Soft starts will not hurt them?

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had the same question. I have two units that are VFD. Soft starts will not hurt them?

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As Downshift mentioned, a VFD soft starts your unit while also varying the speed. If you tested the inrush on it with a meter it would be really low. Earlier in this thread I described the difference:

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VFDs can soft start but soft starters cannot vary the speed of a motor. Once the motor is started the soft starter typically removes itself from the circuit whereas the VFD uses an inverter to vary the speed. That is the main difference with the two devices

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I will have a NG 30KW generator/auto transfer switch installed (haven’t decided on what generator yet), and will need to run two A/C systems (5-ton and 4-ton).

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I think the soft starters will assist in reducing inrush on those compressors but man that is some serious horsepower from that gennie. We’re mostly talking about starting units on a portable 5500W-10kW generator. That 30kW will probably barely feel one of those crank up.

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i have big propane tanks (100lb) and could last 2-3 days with them.

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Should work just fine then. And I agree that testing all your equipment after installing the soft starter is the best plan. If you want some more advice on load management once you test, feel free to pop back in .

Have you tried a local industrial hose supplier? Hose guys in Kenner for example? They can make whatever you want and the prices are generally better than hardware store 0rices for specialty stuff.

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I dont think the soft starter will drop the run amps at all.

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I'm skeptical that it will, but others have stated there was a small drop. I'm thinking there was simply a difference in clamp on meter reading versus soft start data reading.

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Main reason my ac manufacturer approved this device...

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That was my question.. I have a 5 ton Trane still under warranty. Will a softstart installation void my warranty?

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Why is it so hard to find 3/4 inch hose over 12 feet? And when you do they want nearly $150-$200 for it.

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Once you get over 1/2 inch prices shoot way up. Keep in mind also that most come with a brass quick connect fitting, and the price difference between 1/2 inch quick connects and 3/4 - 1 inch quick connects is significant.

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Do these soft starts save money on electricity for the ac units or is this just so you can start them with generators?

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There likely isn’t any energy savings but I’ve heard some people tell me the inrush can make the meter jump a bit, so in theory it’s possible. I haven’t really seen that in practice but I also didn’t do a side by side test so I’m unsure.

But yes the main goal is to be able to start with a generator. It should also benefit the compressor to not start across the line every time and hopefully increase the lifespan. I have an R22 unit from 2003 so time will tell for me.