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Member Post posted an update
Hey gents
I have a Carrier AquaSnap air cooled giving me T077 fault – Saturated suction temperature is greater than leaving fluid temperature for 5 minutes. I’ve replaced all sensors and transducers and I’m still getting the fault periodically. Verified all the readouts on the display are accurate to what I’m getting my temp gun/probes.
Is the next step replacing the MBB? Thanks for all help and input in advance.
Member Post, Member Post and Member Post15 Comments-
Are you sure your sensors aren’t backwards?
I don’t have the book in front of me, can you clear it and run the machine for a couple minutes or no?
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@the-chiller-guys yea, verified they are correct and plugged in to the right terminals. It runs and pulls the loop down to within 2F of SP then shuts off on the fault.
The run time of that alarm is 5 mins with the SST being higher than LWT. But when I look at the readouts on the controller, the SST is never higher than LWT.-
@goldie Are you calculating the SSt yourself, or looking at the controller?
could it have the Wrong refrigerant selected in the program? Its a long shot, but if the control thinks it has a refrigerant with a higher SST,
What is your calculated evaporator approach with you doing it from your gauges, and also with the numbers from the machine?
also, whats your EEV position?1
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@the-chiller-guys I am calculating everything with gauges and vs what it shows on the controller.
My pressures read vs what the controller is showing is off but the temperatures are accurate which is weird.
I’ve setup the GPM through the heat x with an ultrasonic flow meter and found it was low so I’ve cleaned the strainer and upped the pumps to achieve better GPM. Thought that fixed the issue.
I haven’t checked what refrigerant it is selected to see but its 410a and these chillers only come 410a.
Customer just called and said it was off again.-
@goldie but the controllers are used in other stuff besides just that machine.
What pressures are off? Which transducers?-
@the-chiller-guys discharge. I’ve replaced both.
I understand the controller calculates the SST but I’ve never actually seen the SST go higher than the LWT on the controller when I’m watching it. Watched it run for 6 hours or so.
I’m going to have to go back obviously so I’ll get the manual with the setup charts and run through everything. Make sure it’s setup properly.
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@goldie What was your measured approach? (Leaving water temp- SST)
Let me know when you think your going back, maybe we can chat on the phone
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@the-chiller-guys on startup when there was a good load, anywhere from 3-5F. Once it got closer to setpoint, 1-2F.
Probably headed there next week. I’ll go through all the setup and see if anything obvious stands out and let you know. If I’m seeing a high approach, I’m going to recommend clean/flush the heat x.
Thank you brother, may need the phone convo 🤙🏼
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@goldie sounds good man, just let me know.
Go through all of the configuration, and if you can grab a running log of all of the data it will help with the troubleshooting if we need to chat
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@the-chiller-guys I have read through the tables and charts, don’t see a table to change the refrigerant type. I do not see a slot anywhere where you can change the refrigerant type or even put an offset or calibrate the temp sensors or transducers. Am I missing something?
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@goldie you cant put offsets in these, if they are off, they need to be replaced.
I just went through the manual on this one, looks like everything is configured for the refrigerant from the factory in the EEV board, so thats probably not it, unless the eev board was recently changed.
When you go back, check the following, then call me.
1. Go through the configuration starting on page 104, and make sure someone didin’t mess with the EEV settings.
2. SSH setting for the EEV, the book calls for a 9°F ssh setting from the book.
3. Run through the EEV Troubleshooting procedure starting on page 54 of the manual, and make sure everything is working correctly.
4. Check the Pressure Drop Across The Evaporator, and compare it to design.5. Note down any discrepancies with configuration, or sensors/transducers that are off, Write down our operating readings, and call me.
i think i gave you my cell in the past right?
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@the-chiller-guys did not give me your cell and if you did I didn’t put it in my phone.
I’m headed back there now and will record everything
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@goldie Check you private messages
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See if your EXV setpoints are set too low. There is a superheat and approach setpoint into the EXV menu. Otherwise, maybe, the EXV is hanging up and flooding the evaporator. Watch your superheat and where it is while it’s running. 1-2 degree approach is low for that machine. Under full load it should be around 8-10°
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@micho-tankosic thanks for the advice 👍 I’ve ran through the setpoints for the whole machine and everything is per sec. I adjusted the SH SP to make sure the EXV was bouncing around and not stuck or hanging up and it was ok. Both transducers are significantly off from my gauge readings as well.
I’ve talked with Carrier about it and they have recommended a software update or installing a new MBB board. Going to install the new board and I’ll post back what my findings were.
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