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dolce
02-11-2008, 11:00 PM
Hi all
What are the damages if i install comprossor was designed to work in -32C :-36C suction pressure in system work -42 C: -45 C ? the comprossor is Grasso screw

dolce
03-11-2008, 02:23 PM
Is this asking difficult or no one understand me ?

abet_meneses
03-11-2008, 03:05 PM
dolce,

Operating a compressor beyond its specified performance capacity will only lead you to compressor trouble,broken valves.piston ,connecting rod,seized crankshaft etc.Better stick to what is specified.

regards,

abet_meneses
03-11-2008, 03:13 PM
Dolce,

operating the compressor beyond its performance capacity will only lead to mechanical trouble like broken valves,piston,connecting rod,seized crankshaft etc.

regards,

Lowrider
03-11-2008, 03:22 PM
Could also be: No problem, just less or more capacity!

Usually compressors are made for more then just one suction temperature.

You'll have to get hold of a table from the manufacturer. This will show what refrigirants you can use and at which suction temperatures and condensation temperatures and what the capacity of the compressor will be. (Plus displacement etc.!!)

So no straight forward answer! You can if the manual says you can! And if the system around it is designed correctly.

US Iceman
03-11-2008, 04:03 PM
It is not a simple question to answer. You have to look at the limitations of the compressor. You can get these from the manufacturer.

Pressure ratio should not be exceeded. This can greatly decrease the compressors life due to increased wear.

Lower suction temperatures can greatly reduce the compressor capacity. Yes, the evaporating temperature will decrease, but the capacity will also. So, you have to balance the lower temperature with the lower capacity. Getting colder is NOT always the answer.

dolce
03-11-2008, 06:57 PM
many thanks for your replies

TXiceman
04-11-2008, 03:31 AM
Partically depends on which series GRasso screw. The manufacturers publish the normal operating limits in their literature, so look there first. They usually have a minimum suction temperature and a maximum pressure differential pressure (not pressure ratio) across the compressor.

Forgot to ask, is the machine in high stage service or booster service?
What is the compressor Vi?
What is the refrigerant?
What type oil cooling?
Which compressor series?
What type evaporators?

Even if it has the wrong Vi slide valve, it will most likely run at the new conditions, but the efficiency will drop off more.

Good luck.

Ken

dolce
04-11-2008, 05:36 PM
Partically depends on which series GRasso screw. The manufacturers publish the normal operating limits in their literature, so look there first. They usually have a minimum suction temperature and a maximum pressure differential pressure (not pressure ratio) across the compressor.

Forgot to ask, is the machine in high stage service or booster service?
What is the compressor Vi?
What is the refrigerant?
What type oil cooling?
Which compressor series?
What type evaporators?

Even if it has the wrong Vi slide valve, it will most likely run at the new conditions, but the efficiency will drop off more.

Good luck.

Ken
Dear Mr. Ken
Greetings to you.here it's data sheet i'm sorry becaus i wrote type of comp. grasso but is'nt
Product name / SAB 283 L
Product Group / Screw comprossor unit
Evaporation Temperature C -36 C
Intermediate Temprature Saturation-9 C
Refrigerant / R717
Oil Type /M 300
Oil cooling system /Refrige.
VI Man/Auto /Auto

Grizzly
04-11-2008, 06:06 PM
Dolce.
I would just like to point out that a SAB 283L
Is manufactured by Sabroe
and is defiantly nothing to do with Grasso!
I will see if I can upload some tech data that should clarify your question!(shortly)
Grizzly

Grizzly
04-11-2008, 06:24 PM
Dolce.
As there are several detailed options.
Could you let us know what refrigerant you are using?
Grizzly

nh3wizard
04-11-2008, 06:31 PM
Dolce.
As there are several detailed options.
Could you let us know what refrigerant you are using?
Grizzly


Grizzly, It looks like its ammonia (R717) according to his last post.

Grizzly
04-11-2008, 07:16 PM
Grizzly, It looks like its ammonia (R717) according to his last post.

As they say "Good point .Well presented."
Silly me!
O.K. What does type of comp. grasso but is'nt mean?

I will try and upload more as I promised
but my initial feeling is it's to low!
Grizzly

dolce
04-11-2008, 07:37 PM
O.K. What does type of comp. grasso but is'nt mean?

I will try and upload more as I promised
but my initial feeling is it's to low!
Grizzly[/quote]
I'm pleasure for your reply I mean there are mistake in my frist thread i wrote wrong type of comprossor

josef
04-11-2008, 08:02 PM
Sabroe SAB 283 L
Suction pressure - Low warning+alarm -1,0 bar.

nh3wizard
04-11-2008, 08:15 PM
As they say "Good point .Well presented."
Silly me!
O.K. What does type of comp. grasso but is'nt mean?

I will try and upload more as I promised
but my initial feeling is it's to low!
Grizzly

:D Was just trying to help, Im not sure if it has a fixed VI or if its variable / auto.

josef
04-11-2008, 08:22 PM
Please watch for oil