Please help with these questions!!

[tsl001]

Hi everyone,

I have to have these questions answered by tomorrow and my internet crapped out on me. (You can always count on Murphy!!) So it is hard to research on the net right now.

Anyway I do have dialup speed at this time so luckily
I can post these questions.

It will be a good refresher for most.

What is a supermarket rack?

What are the typical case evaporator temperatures found in racks?

What is an oil separator?

What is an oil reservoir?

On a rack or multiple compressor system how does the oil level maintain in the compressors?

What types of compressors are typically found on supermarket racks?

What types of *****s are typically used today in supermarkets?

What is split condenser used for?

What do most supermarkets use to make hot water?

If the hot water reclaim falls below temperature how is it raised normally?

What is heat reclaim used for?

How does it work? (Heat Reclaim)

Name 5 common types of valves found on rack systems?

What is the difference between an ORIT valve and a SORIT valve?

Explain how a TXV works. ____ What does the “E” typically mean at the end of the letters on a TXV id?

What does a manual stem do and where is it found?

What is a charge element or power head?

What is a stepper valve? ___– What operates it?

What are the 3 main styles of defrost used in supermarkets today?

What type of valve is a suction stop?

What are common names for the following valves, cond flood control, evap pres reg, cond pres reg?

Where are flo-con valves typically used?

Name 3 types of dryer cores commonly used on rack systems?

What is an OF303, 303t, 303BP, S4004, S4005?

What is the difference between an MKC1 and MKC2 and what are they ?

What type of brazing rod is most commonly used for supermarket work?

When is it necessary to use 45% cad free silver solder?

What types of flux can be used on refrigeration pipe?

What are the procedures for brazing in a solenoid valve with extended solder ends?
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What is the main difference between oxy / acetylene and acetylene only brazing?

What is a compound rack?

Name 4 rack manufacturers?

Name the most common control systems for supermarket racks,

What is meant by the term “self contained unit”?

What does the term ASH heaters refer to. Where are they found?

What does a digital output point do?

What does an analogue output point do?

What does a transducer do?

What type of signal does it typically produce?

What is a VFD? ___. What is its main purpose?

What has recently changed with regard to Copeland compressor ratings.?

Name 2 screw compressor manufacturers?

I bet some of you can answer these questions in 10 minutes!!

Thanks Everyone!!

Tracy

[The Viking]

This must be that american term "cramming"?

Too many questions and too little time, surely you would have had a term or so to learn all this?

Sorry, but good luck at your test tomorrow.

P.S. The best thing you can do now is to go to bed, you will perform much better tomorrow if you are well rested.

[eggs]

Fark me, forget it you've failed. Go and get a job in banking, i believe they're busy.

eggs

[tsl001]

Hey Guys,

These answers are not a test!

I thought this forum was for helping others!

I guess this is not a forum I want to be a member of after all.

[The Viking]

OK,
That's fair, you have a nice life...




Thing is, your first post to our nice and friendly forum didn't start with something like:
-Hi, I'm John Doe from sunny/windy/rainy/snowy [delete as appropriate] xxx. Currently I'm working my way through xxx and I really would appreciate if someone could help me by answering some of these questions that have been given to me because of xxx...

Instead you throw us a list of every question there is in the book about supermarket rack systems.

If you want friendly and helpful answers, it helps if you put a bit of effort in to learn to know us first.


Any way, as I said before, good luck.

[tsl001]

Your right,

"If you want friendly and helpful answers, it helps if you put a bit of effort in to learn to know us first."

I have learnt that the first impression I get from both you and eggs is that you are not the friendly type at all.

You could not wait to make an arrogant reply to my first post.

I hope you are not this welcoming to all new forum members.

You have a nice life also...

[Gary]

My idea of helping others is you pull and I'll push. If you don't pull then I don't push. We are not here to do your work for you.

42 questions and you need the answers by tomorrow. Sounds like a test to me.

[US Iceman]

I think it is safe to say, most of us grew up in an era where you had to show some ambition and effort to be successful. I for one, along with others here have been to school for this trade and we had no internet. In those dire straits we often found ourselves studying, in advance, to gain the understanding to pass an exam.

I believe most RE members will unselfishly respond to reasonable requests for help with explanations, if, it appears the student asks for help in explaining a specific topic.

However, posting a laundry list of questions and expecting answers is a bit much to ask for.

Let me use an example from the list: What is an oil separator?

Now think about this before you try to get spun up. If you actually expect someone to answer this question, when you obviously did not consider this yourself. My response is; Why go to school if someone else does your work for you?

You may have been expecting too much help, so you might consider this tough love.

If you think this is unreasonable, you should have had some of the senior guys that taught me. I would have gotten smacked for asking this type of question.

[tsl001]

I was not asking for anyone to do the work for me. I know most of the answers. There are a few I am not too sure of. I was just wanting to verify my answers and brush up on the ones I did not know.

I guess I should not have presented the post like I did.

I would have found the answers myself but my stupid internet has dropped from 6mb sec download to 33kb sec.

It is difficult to review answers and question with this crappy speed.

I have answered most of the questions myself.

[tsl001]

Could someone please review and possibly help with the answers I am not too sure about.

Thank you!

What is a supermarket rack? Multiple compressors on one system that refrigerate a series of food cases, walkins and ice machines.
What are the typical case evaporator temperatures found in racks? -35degrees (ice cream) -25degrees (frozen foods) +20degrees (medium temp foods)
What is an oil separator? Seperates the refrigerant oil from the refrigerant to prevent loss of oil into the system.
What is an oil reservoir? A vessel that stores the separated refrigerant oil and the oil required for use of the compressors.
*On a rack or multiple compressor system how does the oil level maintain in the compressors?
What types of compressors are typically found on supermarket racks? Recipricating
What types of *****s are typically used today in supermarkets? R22 and R404a
What is split condenser used for? Heat reclaim
What do most supermarkets use to make hot water? Split Condenser/Heat Reclaim
*If the hot water reclaim falls below temperature how is it raised normally?
What is heat reclaim used for? To heat hot water for the store and save money.
How does it work? (Heat Reclaim) Hot gas is bypassed to the heat reclaim coil which is used to heat the water in the vessel which also helps pull the
heat from the refrigerant.
Name 5 common types of valves found on rack systems? EPR,CPR,Holdback,TXV, Check valves
What is the difference between an ORIT valve and a SORIT valve? ORIT is a fixed setting (Direct acting) - SORIT is self adjusting (Pressure Regulating)
Explain how a TXV works. ____ What does the “E” typically mean at the end of the letters on a TXV id? Metering device that regulates the flow of
refrigerant into the evaporator. E means equalized.
What does a manual stem do and where is it found? Used to manually open a solenoid valve. Located inside the valve body. Adjusted on the bottom.
What is a charge element or power head? It controls the operation (metering) of the TXV and is attached to the TXV. .
What is a stepper valve? ___– What operates it? A valve in a refrigeration system that modulates the flow of refrigerant and it is controlled by a motor.
What are the 3 main styles of defrost used in supermarkets today? Electronic, hot gas/cool gas, time off.
What type of valve is a suction stop? EPR Valve.
What are common names for the following valves, cond flood control, evap pres reg, cond pres reg? Head pressure control valve, EPR/orit/sorit, CPR.
Where are flo-con valves typically used? FLO-Con is the brand name of a valve that is used in refrigerations systems. (Flow Control) CPR, EPR etc.
*Name 3 types of dryer cores commonly used on rack systems?
*What is an OF303, 303t, 303BP, S4004, S4005?
What is the difference between an MKC1 and MKC2 and what are they ? The voltage is differant 115/208-240. Solonoid Coils.
What type of brazing rod is most commonly used for supermarket work? I usually use 15% rods.
When is it necessary to use 45% cad free silver solder? To solder copper to brass.
What types of flux can be used on refrigeration pipe? Never us Acid. Try not to use any if possible. Paste flux for silver soldering.
What are the procedures for brazing in a solenoid valve with extended solder ends? Remove solenoid stem and spring to prevent damage. Wrap with wet rag.
What is the main difference between oxy / acetylene and acetylene only brazing? OXy/acetylene is hotter than just acetylene.
*What is a compound rack?
Name 4 rack manufacturers? Tyler, Hussman, McQuay, Crack
Name the most common control systems for supermarket racks? CPC, Einstein
What is meant by the term “self contained unit”? A unit which contains all the refrigeration componants in one case/unit.
What does the term ASH heaters refer to. Where are they found? Antisweat heater found on the product cases to prevent condensation (Sweating)
*What does a digital output point do?
*What does an analogue output point do?
*What does a transducer do?
*What type of signal does it typically produce?
What is a VFD? ___. What is its main purpose? Variable Frequency Drive. To adjust motor speeds.
*What has recently changed with regard to Copeland compressor ratings.?
Name 2 screw compressor manufacturers? Copeland, Carlyle.

The questions with the stars I am not too sure about!

[750 Valve]

Could someone please review and possibly help with the answers I am not too sure about.

Thank you!

What is a supermarket rack? Multiple compressors on one system that refrigerate a series of food cases, walkins and ice machines.
What are the typical case evaporator temperatures found in racks? -35C (ice cream) -30C to -25C (frozen foods) -12C to -3C (medium temp foods) 0C to +5C (hi temp)
What is an oil separator? Seperates the refrigerant oil from the refrigerant to prevent loss of oil into the system.
What is an oil reservoir? A vessel that stores the separated refrigerant oil and the oil required for use of the compressors.
*On a rack or multiple compressor system how does the oil level maintain in the compressors? by use of a low side float connected to each comp (oil level control) or electronic oil level control
What types of compressors are typically found on supermarket racks? Recipricating, scroll or screw
What types of *****s are typically used today in supermarkets? R404a, R134a - R22 on older plants but is not enviro friendly
What is split condenser used for? capacity control of the condenser under low ambient conditions and during heat reclaim
What do most supermarkets use to make hot water? a water preheater - uses racks discharge gas to preheat water coming into their hot water system
*If the hot water reclaim falls below temperature how is it raised normally? i think they are looking for the answer of a discharge pressure offset to run higher cond tempos - this is not energy efficient and is not practiced on the stores in australia
What is heat reclaim used for? To reject the heat the evaporators remove and reuse it for another task - sometimes it is heating water, sometimes it is heating the shopfloor using a DX coil.
How does it work? (Heat Reclaim) Hot gas is bypassed to the heat reclaim coil which is used to heat the water in the vessel which also helps pull the heat from the refrigerant or is diverted to an air cooled coil in the AHU and used to warm the shopfloor.
Name 5 common types of valves found on rack systems? EPR,CPR,(Holdback?),TXV, Check valves, ball valves
What is the difference between an ORIT valve and a SORIT valve? ORIT is a Direct acting - SORIT is pilot operated
Explain how a TXV works. ____ What does the “E” typically mean at the end of the letters on a TXV id? Metering device that regulates the flow of
refrigerant into the evaporator. E means externally equalized.
What does a manual stem do and where is it found? Used to manually open a solenoid valve. Located inside the valve body. Adjusted on the bottom.
What is a charge element or power head? It controls the operation (metering) of the TXV and is attached to the TXV- it provides one of the necessary forces to regulate the flow.
What is a stepper valve? ___– What operates it? A valve in a refrigeration system that modulates the flow of refrigerant and it is controlled by a bipolar step motor.
What are the 3 main styles of defrost used in supermarkets today? Electronic, hot gas/cool gas, time off.
What type of valve is a suction stop? EPR Valve.
What are common names for the following valves, cond flood control, evap pres reg, cond pres reg? Head pressure control valve (sometimes called a headmaster valve), EPR/orit/sorit, (CPR - a CPR is a crankcase pressure regulator so this is incorrect).
Where are flo-con valves typically used? in the liquid line to provide a pressure difference during defrost, allows saturated gas/condensed liquid to be reintroduced to the liquid line.
*Name 3 types of dryer cores commonly used on rack systems? liquid line dryer, suction felt and burnout (acid removal are 3 that come to mind
*What is an OF303, 303t, 303BP, S4004, S4005? not sure - part numbers suck
What is the difference between an MKC1 and MKC2 and what are they ? The stem diameter is different, voltage can be the same. Solonoid Coils.
What type of brazing rod is most commonly used for supermarket work? I usually use 15% rods.
When is it necessary to use 45% cad free silver solder? To solder copper to brass or steel.
What types of flux can be used on refrigeration pipe? Never us Acid. Try not to use any if possible. Paste flux for silver soldering.
What are the procedures for brazing in a solenoid valve with extended solder ends? Remove solenoid stem and spring to prevent damage. Wrap with wet rag.
What is the main difference between oxy / acetylene and acetylene only brazing? OXy/acetylene is hotter than just acetylene.
*What is a compound rack? 2 stage compound compressors fitted or rack is designed to provide 2 stages of compression with no open intercooler or intermediate vessel
Name 4 rack manufacturers? Tyler, Hussman, McQuay, Crack, linde, bitzer austral, frigrite, (last 2 are aussie )
Name the most common control systems for supermarket racks? CPC - Einstein, Danfoss - AK255SC
What is meant by the term “self contained unit”? A unit which contains all the refrigeration componants in one case/unit - condensing unit mounted above/below case.
What does the term ASH heaters refer to. Where are they found? Antisweat heater found on the product cases to prevent condensation (Sweating) found around doors or case perimeters that may fall below dew point
*What does a digital output point do? basically a switch, is used for on/off control using a signal sent from controller
*What does an analogue output point do? produces a variable signal - 0 to 10V DC or 4 to 20 mA to control something in infinite steps
*What does a transducer do? converts one form of energy to another, eg, senses pressure and turns it into an analogue signal (0-10V DC or 4-20mA) for an electronic controller to read, can also be used to sense temp, RH, power among others
*What type of signal does it typically produce? see above - analogue 0-10V DC or 4-20 mA
What is a VFD? ___. What is its main purpose? Variable Frequency Drive. To adjust motor speeds.
*What has recently changed with regard to Copeland compressor ratings.? not too sure sorry, don't use copelands much mainly bitzers
Name 2 screw compressor manufacturers? Copeland, Carlyle.

The questions with the stars I am not too sure about!

seeing as you had a crack I have added some info in red for you

[tsl001]

Thank you very much 750 Valve.

I owe you a beer!

I will thoroughly review the answers that I did not know. I am trying to improve my knowlege on rack systems so I can move to that department of my job.

[Gary]

On driers, the numbers refer to core and connection sizes. For example, 303 is a 30 cubic inch core and fits a 3/8 line. 162 is 16 cubic inch for 2/8 (1/4") line.

I'm thinking OF303 is a 30 cubic inch 3/8 oil filter, and I believe 303BP is a bypass filter.

[tsl001]

Thanks,

I had a feeling that they were numbers for liquid line driers but I have not seen these numbers before!

[Brian_UK]

On driers, the numbers refer to core and connection sizes. For example, 303 is a 30 cubic inch core and fits a 3/8 line. 162 is 16 cubic inch for 2/8 (1/4") line.

I'm thinking OF303 is a 30 cubic inch 3/8 oil filter, and I believe 303BP is a bypass filter.

As an aside to this thread topic I was interested to see Gary give a measurement as 2/8 for 1/4".

When buying some fluorescent tubes the other day I was informed that they are still sized on the American way which is multiples of 1/8"

Hence tube sizes are T5 or T8.. T5 = 5/8" diameter and a T8 is 1" (8/8ths)

Another piece of information to store away ready for the next pub quiz.

[Gary]

And in England they drive on the left side so that their right arm is free for jousting.

[Porkington]

And in England they drive on the left side so that their right arm is free for jousting.

Its actually so your right arm is free to hold your mobile phone....

[The Viking]

Its actually so your right arm is free to hold your mobile phone....

Bet you get less fine/points for jousting

[Gary]

Nonetheless, that's how the whole left side of the road thing got started. Right handed opponents on horseback approaching each other to do combat with lance or sword. (You will need to know this for the next pub quiz)

[Smart42]

Could someone please review and possibly help with the answers I am not too sure about.

Thank you!

What is a supermarket rack? Multiple compressors on one system that refrigerate a series of food cases, walkins and ice machines.
What are the typical case evaporator temperatures found in racks? -35degrees (ice cream) -25degrees (frozen foods) +20degrees (medium temp foods)
What is an oil separator? Seperates the refrigerant oil from the refrigerant to prevent loss of oil into the system.
What is an oil reservoir? A vessel that stores the separated refrigerant oil and the oil required for use of the compressors.
*On a rack or multiple compressor system how does the oil level maintain in the compressors?
What types of compressors are typically found on supermarket racks? Recipricating
What types of *****s are typically used today in supermarkets? R22 and R404a
What is split condenser used for? Heat reclaim
What do most supermarkets use to make hot water? Split Condenser/Heat Reclaim
*If the hot water reclaim falls below temperature how is it raised normally?
What is heat reclaim used for? To heat hot water for the store and save money.
How does it work? (Heat Reclaim) Hot gas is bypassed to the heat reclaim coil which is used to heat the water in the vessel which also helps pull the
heat from the refrigerant.
Name 5 common types of valves found on rack systems? EPR,CPR,Holdback,TXV, Check valves
What is the difference between an ORIT valve and a SORIT valve? ORIT is a fixed setting (Direct acting) - SORIT is self adjusting (Pressure Regulating)
Explain how a TXV works. ____ What does the “E” typically mean at the end of the letters on a TXV id? Metering device that regulates the flow of
refrigerant into the evaporator. E means equalized.
What does a manual stem do and where is it found? Used to manually open a solenoid valve. Located inside the valve body. Adjusted on the bottom.
What is a charge element or power head? It controls the operation (metering) of the TXV and is attached to the TXV. .
What is a stepper valve? ___– What operates it? A valve in a refrigeration system that modulates the flow of refrigerant and it is controlled by a motor.
What are the 3 main styles of defrost used in supermarkets today? Electronic, hot gas/cool gas, time off.
What type of valve is a suction stop? EPR Valve.
What are common names for the following valves, cond flood control, evap pres reg, cond pres reg? Head pressure control valve, EPR/orit/sorit, CPR.
Where are flo-con valves typically used? FLO-Con is the brand name of a valve that is used in refrigerations systems. (Flow Control) CPR, EPR etc.
*Name 3 types of dryer cores commonly used on rack systems?
*What is an OF303, 303t, 303BP, S4004, S4005?
What is the difference between an MKC1 and MKC2 and what are they ? The voltage is differant 115/208-240. Solonoid Coils.
What type of brazing rod is most commonly used for supermarket work? I usually use 15% rods.
When is it necessary to use 45% cad free silver solder? To solder copper to brass.
What types of flux can be used on refrigeration pipe? Never us Acid. Try not to use any if possible. Paste flux for silver soldering.
What are the procedures for brazing in a solenoid valve with extended solder ends? Remove solenoid stem and spring to prevent damage. Wrap with wet rag.
What is the main difference between oxy / acetylene and acetylene only brazing? OXy/acetylene is hotter than just acetylene.
*What is a compound rack?
Name 4 rack manufacturers? Tyler, Hussman, McQuay, Crack
Name the most common control systems for supermarket racks? CPC, Einstein
What is meant by the term “self contained unit”? A unit which contains all the refrigeration componants in one case/unit.
What does the term ASH heaters refer to. Where are they found? Antisweat heater found on the product cases to prevent condensation (Sweating)
*What does a digital output point do?
*What does an analogue output point do?
*What does a transducer do?
*What type of signal does it typically produce?
What is a VFD? ___. What is its main purpose? Variable Frequency Drive. To adjust motor speeds.
*What has recently changed with regard to Copeland compressor ratings.?
Name 2 screw compressor manufacturers? Copeland, Carlyle.

The questions with the stars I am not too sure about!

Even though I have just started working for a company that uses rack systems. I'll help where I can.

*What is a compound rack?
a compound rack is normally a low temp rack that uses compressors that are of compound design. Carlyle makes a compressor that is a compound design. These compressors use 2/3 of cylinders to compress the refrigerant from low pressure to Med pressure then it is sent to the last 1/3 to final head pressure. A common model is 06cc.

*What does a digital output point do?
A digital Point (in or out) is basicly an on or off signal of voltage that the control board and read and send.

*What does an analogue output point do?
An analogue point (In or Out) normally uses a varring values of voltage 0-10Vdc or 4-20mvdv

*What does a transducer do?
takes a pressure reading and converts it to an electical signal or visa versia take an eletrical signal and regulates a pressure. basicly this is one of your analoglue devices that connect to your analogue points.

*What type of signal does it typically produce?
I think I covered this in the above 2.

[Peter_1]

Time for so many posts and no time for answering?
So many posts in one day and you lost your internet conncetion?

[Peter_1]

*What is a compound rack?
a compound rack is normally a low temp rack that uses compressors that are of compound design. Carlyle makes a compressor that is a compound design. These compressors use 2/3 of cylinders to compress the refrigerant from low pressure to Med pressure then it is sent to the last 1/3 to final head pressure. A common model is 06cc.

I think you're describing an internal 2-stage compressor.
A compound is where the discharge of the low evaporating pressure compressors is injected in the suction of the high pressure compressors.

In a compound, you need both low and high stage compressors as mainly used in NH3 freezer/cooling flooded combinations.

[taz24]

Nonetheless, that's how the whole left side of the road thing got started. Right handed opponents on horseback approaching each other to do combat with lance or sword. (You will need to know this for the next pub quiz)

Your right partialy

We drive on the left because we mounted and dismounted a horse from the left.

We mounted from the left due to the sword we carried and fought with. The sword was on the left hip so it could be drawn by the right hand and thus mounting a horse from the left was easier when wearing a sword on the left.

It then put us on the correct side to fight with the sword not the lance. It then moved to walking with a lady. We gentlemen would walk with the lady on our left which left our right arm free to draw the sword and deffend the lady.


Right handed people holding the lance in their right hand actualy point the lance across to the left side and thus joust to the right.

taz

[Grizzly]

And at the start of this post It's Member were described as unhelpful.
And at the end we have had a myriad of helpful answers (total respect 750valve- "above and beyond" effort)
Including a social history lesson!
Grizzly

[matt.yelland]

Tahnks all, I have learnt a lot about why we brits drive on the left, added bonus, a little bit more about refrigeration!!!

[Mark]

Tahnks all, I have learnt a lot about why we brits drive on the left, added bonus, a little bit more about refrigeration!!!

Matt,
Hope you are fully recovered mate after your recent problem.
Mark

[Abdul Q Khan]

HI TO ALL MEMBERS
Please help me to answer these questions before monday May 3rd.
1-name 4 things yuo need to know about a system when
replacing a TEV(TXV).
2-what is the purpose of having a distributor on an evaporator?
3-can you charge a system with a TEV by only
measuring superheat?
4-what does the term Volt means.
5-virgin refrigerants means what?
6-what is the advantage of having an automatic pump-down system?
7-by measuring compressor amperage what will
that help us do?
8-are liquid line solonoid valves normaly open or
closed and why?
9-what 2 things must you consider before selecting a
replacement refrigerant for a system?
10-what does the term split system means?

[Peter_1]

Wrong section and certainly if you post it within another thread.

This is not a site where we make your homework.
If you have studied some minutes, then you must be able to answer all these questions.

Give us the answers you already have and we will look then where we can upgrade your answers.
But I bet we will see only one post of you

[cool runings]

HI TO ALL MEMBERS
Please help me to answer these questions before monday May 3rd.
1-name 4 things yuo need to know about a system when replacing a TEV(TXV). Is there any refrigerant inside the system, what refigerant is the system on, is the the valve internal or external equalised and Why does the valve need replacing.
2-what is the purpose of having a distributor on an evaporator? to split the refrigerant trough differant parts of the evap so there is a more even distrabution of temperature.
3-can you charge a system with a TEV by only measuring superheat? Yes but as always it is not a yes - no answer.
4-what does the term Volt means. Its a blokes name.
5-virgin refrigerants means what? They have never had sex.
6-what is the advantage of having an automatic pump-down system? You don't have to do it manualy
7-by measuring compressor amperage what will that help us do? See how hard it is working.
8-are liquid line solonoid valves normaly open or closed and why? Normaly closed, so they close if they fail.
9-what 2 things must you consider before selecting a replacement refrigerant for a system? Cost and environmental impact.
10-what does the term split system means? It is in 2 halves.

Cool runnings

[Peter_1]

Cool runnings, the man can now sleep 2 hours longer this Sunday morning instead of searching the answers, you gave him 50% of the answers in your free time .

[Abdul Q Khan]

Thnk u cool for answering

[D.D.KORANNE]

Reading roy j dossat book on refrigeration would help understand it better . Basics are nicely answered