I have had a Micro Air EasyStart on my 4 ton Rheem unit for 5 years with no problems at all. I did the install myself. My service guy had nothing but praise for them. I can run my AC using my 10kw dual fuel generator. It dropped the inrush current from 118 to 40-60 depending on temperature.
Micro-Air EasyStart Flex - HVAC soft start kit
- Thread starter dnewton3
- Start date
The link to the product is in the OP's second sentence of Post #1.
4wd
$50 site donor 2026
After reading this again - I’m reminded why my guy recommended a soft start that I paid for. He was about to change a compressor under warranty - then said the new one did not reset the warranty clock - but felt the SS was prime mitigation against future issues …
I'm with you.
I have experience with Airgo soft starter. On a new 3 ton with scroll compressor, the inrush current was reduced from ~ 80 amps to 19.x amps. The entire duration of the soft-start seems to be around 1 second.
Seems to me this would benefit the compressor by vastly reducing the sudden surge of current and presumably mechanically as well.
My install is in the third year and works well.
dnewton3
Staff member
I have emailed them and asked for them to address this issue of harmonics as a point of discussion.
I must confess I am at a disadvantage; some of those topics you refer to are beyond my current understanding of how the product works in relation to the unit.
I can say that the graph shows that SS unit only alters current for less than 1 second. Would this topic of "harmonics" be of any real concern if the application period is less than one second total, when the compressor runs for several minutes? It would represent a mere fraction of the total time, and I don't understand how such a minimal duration could "heat up" a compressor. Could you elaborate?
Is this an issue when the SS isn't tied into the fan circuit? The EasyStart Flex inserts into the compressor power "start" lead; it's not even connected to the "run" lead. And it does not involve the fan motor wiring whatsoever.
https://www.microair.net/products/easystart-flex-home-ac-soft-starter
From the installation page:
https://micro-air.com/support-documents/EasyStart/EasyStart-Flex-quick-install-insert.pdf
I understand what you are saying but as a homeowner I didn’t demand an in depth explanation. We work with people we trust based on experience and reputation and generally heed their advice.
From a management perspective, if you have managed an organization of any size you realize that you can only be an expert on a fraction of what passes in front of you. You hire good people, hold them accountable, but otherwise empower them or you tend to demoralize people by becoming a micromanager. My perspective is that this father son duo had no reason to give me anything other than their best advice - they had no financial stake in it - and they have been in business for a long time and don’t even take new customers. So I took their advice and passed it on to you in case the perspective was helpful. Bear in mind that I was calling myself out for making what I think was mistake and wanted to share it to be helpful. Obviously you have a different view that may be appropriate based on the equipment you use but at least with the Carrier or Bryant equipment these folks install they don’t like it. Because it disagrees with what you think doesn’t make it hooey of whatever term you used.
I have looked at the product and I don't see a contactor. Normally, on the products I work with, the SCRs are current limited so that's how they control "soft starting". Back in my Square D days, we sold different types of soft starters.
Part winding, Wye-Delta, Autotransformer, SSRVS (Solid state reduced voltage starter), VFDs, and one other I don't remember right now. The product you have may control voltage and not current - I don't know.
Most of the units Square D sold back in the day have gone by the wayside (like saltwater rheostat motor controllers) because of current model VFDs and SCR driven soft starts.
I am wondering what they will tell you on the power circuit and it's impact on harmonics. Also, I see they list as UL, but I can't tell if it's UL recognized or UL listed. Maybe ask them that question as well.
Okay, I have looked into this a little more. It appears to change capacitance for a short duration as a "boost" - basically acting as a start capacitor and it drops out so the run capacitor can do it's job - and it drops out the starting part within one second or so.
If I am correct in my assumption, then their should be no harmonics and only minimal heating of the motor during the initial starting sequence. The capacitor in the unit is a start capacitor, and that explains the lower initial current draw. Old school PTCR or start cap in a new look, possibly with a thermal modeling setup to look like a variable resistor. I don't know based on what I can find online.
So it's still a "hard starter", but it most likely limits inrush with stored voltage. Interesting new take on old design - again, if I'm seeing it right as there isn't much online in a W/D schematic to review.
Take a look at this videos:
Part winding, Wye-Delta, Autotransformer, SSRVS (Solid state reduced voltage starter), VFDs, and one other I don't remember right now. The product you have may control voltage and not current - I don't know.
Most of the units Square D sold back in the day have gone by the wayside (like saltwater rheostat motor controllers) because of current model VFDs and SCR driven soft starts.
I am wondering what they will tell you on the power circuit and it's impact on harmonics. Also, I see they list as UL, but I can't tell if it's UL recognized or UL listed. Maybe ask them that question as well.
Okay, I have looked into this a little more. It appears to change capacitance for a short duration as a "boost" - basically acting as a start capacitor and it drops out so the run capacitor can do it's job - and it drops out the starting part within one second or so.
If I am correct in my assumption, then their should be no harmonics and only minimal heating of the motor during the initial starting sequence. The capacitor in the unit is a start capacitor, and that explains the lower initial current draw. Old school PTCR or start cap in a new look, possibly with a thermal modeling setup to look like a variable resistor. I don't know based on what I can find online.
So it's still a "hard starter", but it most likely limits inrush with stored voltage. Interesting new take on old design - again, if I'm seeing it right as there isn't much online in a W/D schematic to review.
Take a look at this videos:
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No position on the device. I dont know enough about them other than what is read on both sides of the debate (not just in this forum)
But one part of me thinks too much on all subjects like this.
How slow is "soft start" ? I only ask because I did have a retail store with roughly a dozen compressors of all types for refrigeration, Copeland was one of the bigger brands, both air and water cooled. But forget that, Im just mentioning, I have a little background with compressors including of course standard type HVAC.
Anyway, the reason I ask is how slow is "soft start" is let's say for instance some compressor equipment, and you can buy these devices for even home refrigerators will have a feature that will prevent the unit from trying to start up in low voltage situations. Maybe less common in todays world because utilities know how low they can go with voltage but used to be known as "brown outs"
After typing all this, maybe irrelevant but I do wonder, without that fast jolt of voltage/current with soft start limiting it, is it really better? Why wouldnt this be implanted on higher end units if it was a good thing?
No position, just thoughts of something I didnt research.
But one part of me thinks too much on all subjects like this.
How slow is "soft start" ? I only ask because I did have a retail store with roughly a dozen compressors of all types for refrigeration, Copeland was one of the bigger brands, both air and water cooled. But forget that, Im just mentioning, I have a little background with compressors including of course standard type HVAC.
Anyway, the reason I ask is how slow is "soft start" is let's say for instance some compressor equipment, and you can buy these devices for even home refrigerators will have a feature that will prevent the unit from trying to start up in low voltage situations. Maybe less common in todays world because utilities know how low they can go with voltage but used to be known as "brown outs"
After typing all this, maybe irrelevant but I do wonder, without that fast jolt of voltage/current with soft start limiting it, is it really better? Why wouldnt this be implanted on higher end units if it was a good thing?
No position, just thoughts of something I didnt research.
@alarmguy, In order to have a good idea of it's workings, I need to look at the assembly without the cover and big label covering it. But after a little research, it seems to be a start capacitor added in electronically to lower inrush demand (the W/D shows it taking the place of the start cap).
I don't know if it changes phase angles and it probably does overload the windings for just a brief while, but the windings should be able to withstand that and not sustain damage.
I really want to hear what the manufacturer has to say on this, and I would like to see one with the label out of the way, and both sides of the assembly.
That brings up a memory: anyone remember years ago there were companies selling power factor correction caps to homeowner's (KVAR)? Even though homeowners didn't get penalized for power factor. Big money for a capacitor in a box that did nothing but hum. I put a power quality analyzer on one and the device really didn't do anything. Didn't hurt, but didn't help either.
https://www.nist.gov/news-events/ne...ifies-utility-power-factor-correction-devices
https://www.powerwizard.com/blog/what-is-an-electricity-saving-box-and-does-it-actually-work/
I don't know if it changes phase angles and it probably does overload the windings for just a brief while, but the windings should be able to withstand that and not sustain damage.
I really want to hear what the manufacturer has to say on this, and I would like to see one with the label out of the way, and both sides of the assembly.
That brings up a memory: anyone remember years ago there were companies selling power factor correction caps to homeowner's (KVAR)? Even though homeowners didn't get penalized for power factor. Big money for a capacitor in a box that did nothing but hum. I put a power quality analyzer on one and the device really didn't do anything. Didn't hurt, but didn't help either.
https://www.nist.gov/news-events/ne...ifies-utility-power-factor-correction-devices
https://www.powerwizard.com/blog/what-is-an-electricity-saving-box-and-does-it-actually-work/
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I'm not sure on this particular brand/model of the exact circuitry (Would need a teardown or a gerber/pcb file for that) but usually these types of units switch on the winding that is typically linked to the start capacitor, switching SCRs or triacs( much less common...at least in my experience...which isn't much when it comes to these specifically) though they typically also have a switching path on the run winding that they modulate (I've not looked at the schematic for this unit...). I always try to install them on my home units just to lower the inrush current, I'm not really concerned with a small increase or decrease in the amount of joule heating that occurs during these times, the I2t values are typically reasonablly approximate to each other. I do like them for the lower magnetic forces that the windings typically experience during startup which scale (approximately) quadratic with current. The larger inrush values put more force on the bearings and windings, resulting in higher wear and tear...is it meaningful .....I dunno, never completed a endurance and teardown to fully see. As a nice side effect though it keeps my voltage regulation here at home within a more meaningful band for the rest of my home equipment. Hope you get many many years of service out of it !
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IMO, It's not. If your home is up to date and has a 200A, 300A, or 400A service, you won't even see the lights dim when the compressor turns on.
Most folks worry that it's hard on the motor, but most motors are made to withstand across the line starts per their spec sheets (starts per hour within specified voltage range).
I have customers that have line start 200HP three phase motors. NOW those will dim the lights if the service is week. That's what the SS and VFDs are for now. But, if the motor starter fails, and they need production, across the line it goes.
The biggest killer of home AC compressors I've seen is loss of capacitance on the capacitors for the condenser fan and/or compressor, and short cycling.
dnewton3
Staff member
On the MicroAir website, they do have a FAQ which states they can be wired to other types of equipment. They include a generic wiring diagram.
Given that planers, joiners, table saws, etc are low use (not a lot of hours), I don't know if the savings for lifecycle improvement would ever offset the high unit cost.
