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Member Post posted an update
April 27, 2025 (edited)
Have a tt300 that drives the igv closed for ages everytime it’s turns off or on. I’ve had to replace the igv motor as the gears had failed on a different comp. Is there any settings I can change to sort this out?
On another note I have a second compressor that fails a calibration test and then resets (driving the igv closed even when it is closed) however the compressor runs fine. – yes I’ve unplugged j1 –
the last picture is of a calibration which was able to complete but still failed.
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i cant upload a yenta file here.
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Is it taking a long time to close, or is the controls just holding it closed for a long time, and not opening it?
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@the-chiller-guys nah the motor drives closed for however long it thinks it needs to close even though it’s already closed, the whole mech is clunking away
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@Vas so the mechanism is bad? it sounds like its never getting into speed mode. the IGV should drive open, once it reaches 110% it will switch to speed mode.
Send us a short yenta recording from startup, into operation for a little while
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@Vas from what i can see is its doing it after a control mode change, are you doing this, or is the chiller controller changing the control modes via modbus?
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@the-chiller-guys nah the mech works fine when the chiller is operating. on startup and when It fails a calibration it seems to send a signal to drive the igv closed even though it’s already closed.
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@Vas can you upload that yenta, and I can take a look? It should work now
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@the-chiller-guys yep will do when I get back to site
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Sounds good, we should be able to see whats happening then. Also, can you verify the sensors on the chiller are correct, and fill out a log sheet for the entire chiller once its stable? It could be a number of system problems that put the compressor outside the “Choke” Or “Surge” line, and the BMCC could be overriding the demand to protect the compressor.
with the yenta and a logsheet, we can figure out whats going on.
you can download the diagnostic log sheets from the “Technician Resources” in the “Member Files” Section if you don.t already have them.
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this is during a calibration, if you watch the igv position it jumps back to 110% without actually physically changing, then tries to drive closed again. whilst operating it functions normally.
unfortunately i haven’t got time to do a full test on the compressor at the moment until i get a PO from the customer to do so.
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this one is during normal operation with no faults.
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During calibration, does it draw a decent circle for the front radial bearing ?
What are the gain values on the calibration report ?
What version BMCC ?
It will drive the vanes closed when it initializes, because there is no feed back for the vane position. So it doesn’t know where the vanes are.1-
@joe-patton nah it doesn’t draw a circle at all, maybe a 1/6 of a circle and then fails
Im on holiday at the mo so ill flick through more data in a few days
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@Vas when you get back in front of it, check your bearing sensors and the sensor cables (the cables are known to fail). If any of your gains during a bearing calibration are 0, it’s probably and electrical issue and I would start at the bearing sensor and work back from there.
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There is no way to change IGV stepper motor speed on SMT. It requires in-depth knowledge of the BMCC. As far as the IGV motor, ever time it satisfies and/or clears an alarm it will drive the IGV closed as part of it re-initialization process. No way around it.
If the compressor runs, what’s the reason for bearing cal?-
@J.MC all good, so just an initializing sequence?
Just part of the routine maintenance we check the calibration against the stored.
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