The ISD controllers can be troublesome. Go off line like a regular cpc board and cause issues..
when it runs in fail safe the manual high and low safety come into play and they use the non adjustable screw on style which suck..the settings are way to low for 404 med temp causing the rack to run flat out.
The nice part about the ISD is you can monitor amperage, cycle counts, dis temp, suct temp all together.
Copeland has a hard on for this all because they are trying to go with scrolls in most apps. They wished it was scroll all the way. But they got to deal with the recip market. There is simply too much demand to ever depart from it. So in stead of doing what almost everyone else has done, using drives on recips, they figure if they can run a recip like they do their scrolls, with the same POS control using PULSED WIDTH MODULATION. To understand this all you have to do is understand the PWM is nothing more than 20 second windows. In them 20 seconds, it will be determined by set point how long loaded and unloaded the pump will be in that capacity. It can be very choppy suction. It's okay but don;t expect miracles with it.
After working with a few drives, and then you go try and tweak one of these digital controllers, it's night and day. The digital control sucks. On a rack with constant load changes the suction can be very choppy. On singles it's worse. Frequency drive is the only way these days. It's getting cheap.
Additionally, they have yet to come out with a integrated single control for it. You have to have like a AK255 or an e2 to run it. Let's say you wanted to do this to a single. Like we all talk about on here, where you have a single with multiple loads. You can not deploy this with out something like a rack controller because it needs the analog input and set point reference. A guy can do it with temperature using the digital stats. But I have not seen a contraption that will do analog for pressure.
I went to a seminar a few months back and this dude was touting this as the next big thing. SO I asked him and informed him of how choppy and how not tight of control it is. He tried hard to shut me up in front of the audience. And I don't even think he or the audience was understanding what I was saying. I don't think they understood choppy. Or how I was trying to explain tight suction.
If the cycle window could decrease to 3-5 seconds , it would be so much better. I think now it's a 10-20 second window.( I forget)
The thing that makes me laugh is that they are bragging about unloading down to 10% ( if I remember)...yeah that's impressive but, That's 100% compresser for 1 second and unloading for 9 sec.( or whatever the window is).
If it was CFM reduction from (example) 1000 CFM to 100 CFM I'd be impressed. If 100$ bills came out of my dogs behind..I'd be impressed.
If my credit cards were suddenly payed off...well you get it.
But at the shorter window the valve would probably die much quicker death(too many cycles)
A VSD on an E2 is the stuff , if all is dialed in correctly. But you still have low limits for oil issues.