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Thread: Bitzer Compressor
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19-01-2022, 10:59 AM #1
Bitzer Compressor
Hello guys,
Need some help please from yourselves who have experience on a CSH7573-90Y Bitzer compressors controlled by am inverter.
Have attended a site where they are suffering from high discharge temperatures. Recently carried out a coil clean to which they dropped around 20 degrees less than normal.
However, after this they started to go above 85 degrees, aware Bitzer state higher degrees but looks like compressor keeps tripping on high temperature sensor, has a new temp sensor and motor protection module when installed, these units do suffer air recirc but only bad in the summertime, oil level is good ok. Bit lost atm.
Looking into liquid injection for these, wondered if anyone had any opinions on this?Last edited by Stretch79; 19-01-2022 at 11:26 AM.
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19-01-2022, 11:26 AM #2
Re: Bitzer Compressor
Thought I'd add the noted running conditions.
Discharge temp - 69.4
Condensing pressure - 16.2B
Evap temperature - 13.1
Evap pressure - 4.8B
Liquid line temp 36.3
Air on condenser - 14.3
Air off condenser - 24.6
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Re: Bitzer Compressor
Does it have an oil cooler?
I've commissioned a similar one a couple of years ago and I think we ran with 18bar discharge, no issues with the discharge temp.-Cheers-
Tycho
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19-01-2022, 04:49 PM #4
Re: Bitzer Compressor
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19-01-2022, 06:06 PM #5
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Re: Bitzer Compressor
Hi
You can go to liquid cooling or ECO .System
Both helps you to bring discharge temp down
But ECO. much better than liquid Injection
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19-01-2022, 08:01 PM #6
Re: Bitzer Compressor
Stretch,
Had a look but could not find, but discharge temperature cut out I think is 105 deg C.
Suction superheat might increase a little bit, but 69.4 degC sounds good.
Not sure what refrigerant you are using though.
Consider changing oil filter if you have not done already & if has extended pump down period can get hot.
Oil temperatures usually up to 70 deg C with or without oil cooling.
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19-01-2022, 08:26 PM #7
Re: Bitzer Compressor
It's impossible to make anything foolproof because fools are so ingenious...
Don't ever underestimate the power of stupid people when they are in large groups.
Please, don't teach me how to be stupid....
No job is as important as to jeopardize the safety of you or those that you work with.
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21-01-2022, 09:09 AM #8
Re: Bitzer Compressor
Morning all,
Sorry should of mentioned the fridge type. Appreciate all your input
It is running on R407C.
The discharge temps have crept up to 70 odd degrees C which is not bad but the housing is very hot to touch.
This is running at 100% for the compressor, the secondary compressor has failed so only one operational, have changed recirc. time to 720 secs from 360 to help limit the starts.
This suffers as most probably do at this time of year, due to lack of heat load.
New compressors, new oil charge and new filters, re manufactured by Bitzer units.
Will have to look into the ECO side of things, only looked at the injection part.
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21-01-2022, 10:04 AM #9
Re: Bitzer Compressor
Stretch,
You must have written incorrectly, as R407c more like 1.8 b low pressure.
As Josip mentioned discharge pressure high for low ambient.
Discharge temperature fine, but would be lower if discharge pressure lowered.
SCT 45 deg C in 14 deg C ambient.
I don’t think economiser would really help on low load, only if compressor 80-100 % loaded.
you do not mention room temperature or whatever this unit is cooling, which is also important.
You do not want sustain pressure any lower than necessary.
What is minimum load for compressor, 50%?
Units have worked on in the past have 7 minute LST, but your 12 minute better.
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21-01-2022, 01:05 PM #10
Re: Bitzer Compressor
Hello Ranger,
Isn't that rather low 1.8B for R407c, would expect that pressure from R134A?
This chiller is feeding fan coil units within apartments, water cooled.
Compressor is on an inverter, used to be staged but that has been changed, believe minimum is 33% not 100% sure on this.
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21-01-2022, 07:02 PM #11
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24-01-2022, 02:35 PM #12
Re: Bitzer Compressor
This is a big block of flats that is mainly glass panels so cooling is required albeit low loads high starts for the chiller.
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24-01-2022, 08:20 PM #13
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25-01-2022, 10:47 AM #14