OK Lets take a vote.

[slingblade]

Im sure most of you will have heard about Marc o'brien and his recent 2k temp. drop over a drier article in service engineer magazine.
Question:- If a 2k temp drop is an industry standard rule of thumb that requires a drier change how many of you have done it?

[rbartlett]

Sling

I seriously thought you were over this nonsense..

Why not come up with a written paper on why and where you think this is wrong rather than try to turn it into a personality contest ?

The paper was written in order to get engineers questioning the status quo rather than running away shouting "I can't hear you ,I can't hear you"

I was always tought to change the drier whenever the system was 'broken into' both for moisture and financial reasons...

Either way I was not taught to 'wait till it blocks' nor would I recommend this as acceptable from my engineers...So I must admit I'm shocked that you feel this could ever be considered 'good refrigeration practice'


Cheers

Richard

[Andy]

Hi:)

we change all the driers on our industrial sites every year:)
Probably a little over the top, but by changing the driers, checking changing the oil, cleaning the condensers and tightening the electrical connection we remove nearly all the call outs to condensing units bar the usual freeze ups.

I have long suspected that driers deteriorated over the years and that temperature drop accross them was no real indicator on the drier state.

Another one to watch is which drier you fit with a new compressor. If the unit runs on Ester oil there is an additive used to increase boundary lubrication. Most people change the drier when fitting a compressor, for the first run after new a different drier is required that does remove the additives for boundary lubrications.

A drier is an important component in any system, requiring a little consideration:)

Kind Regards Andy:)

[slingblade]

I for one have never heard of this "industry standard rule of thumb".

Take for example a brand new 50kw air cooled water chiller and as a comissioning engineer you encounter the 2k drop, do you change it?

what if still has a 2k drop with a new one.

I fully agree that a system should have a new drier when broken into, but why break into one just to fit a drier unless it is BLOCKED?

I am neither running away nor shouting i cant hear you but canvassing the opinion of fellow engineers on what i feel is a rather odd subject.

No personality contest intended.

regards

sling.

[Brian_UK]

I have to agree with Richard here Slingblade, have you written to the magazine concerned to discuss the article yet and if not, are you going to ?

I haven't read the article so will not comment on it directly here as it is not the place.

[rbartlett]

I for one have never heard of this "industry standard rule of thumb".

Take for example a brand new 50kw air cooled water chiller and as a comissioning engineer you encounter the 2k drop, do you change it?

what if still has a 2k drop with a new one.

I fully agree that a system should have a new drier when broken into, but why break into one just to fit a drier unless it is BLOCKED?

I am neither running away nor shouting i cant hear you but canvassing the opinion of fellow engineers on what i feel is a rather odd subject.

No personality contest intended.

regards

sling.

If I saw a sight glass that was yellow I would change the drier whether it was 'blocked' or not, I actually wouldn't even test the drier -it would be a natural swap out .

Plus preventative maintenance as Andy mentioned is another reason to change driers.


Your second point is like saying "what if the drier was blue and you changed it and it was still blue what then?"

Cheers

Richard

[chillin out]

You should change driers only when you have to or when the comp is replaced.

Doing this any other time just proves you have too much time/money on your hands.

It would be nice to change the drier when we wanted to but there is always someone else pulling the strings.

Chillin:) :)

[slingblade]

I have to agree with Richard here Slingblade, have you written to the magazine concerned to discuss the article yet and if not, are you going to ?

I haven't read the article so will not comment on it directly here as it is not the place.


Brian,
I have not written to service engineer magazine for the simple reason that i saw no need to. I can understand your view that this is not the place to comment on the article but there has been a thread started on this forum by someone else directly questioning the subject posed in the article. I notice your opinion does not relate to that particular thread, only mine.


If I saw a sight glass that was yellow I would change the drier whether it was 'blocked' or not, I actually wouldn't even test the drier -it would be a natural swap out .

Plus preventative maintenance as Andy mentioned is another reason to change driers.



Two very good points i am in full agreement with.
However neither are in discussion here, what is being questioned is the bizzare generic rule of thumb whereby a drier needs immediate replacement when a 2k temp. drop is found.

Your second point is like saying "what if the drier was blue and you changed it and it was still blue what then?"

I do not understand this richard. the colour of the drier is irrelevant. I thought my point was quite clear, but i will explain further.
If a drier is changed because of this 2k temperature differential and the new drier still shows a 2k temperature differential does it need replacing again?
No, clearly it did not need replacing in the first place.


You should change driers only when you have to or when the comp is replaced.

Doing this any other time just proves you have too much time/money on your hands.

It would be nice to change the drier when we wanted to but there is always someone else pulling the strings

Thank you.
Common sense prevails.


I notice also that the poll is starting to prove this point.;)


Regards


sling.

[fixit]

Hello folks
Two things, i agree with Richard, dont like the carry on,
also can you be sure you are getting 2 oC difference, usually dry roasted one side the other wet cold.
Must get my self a copy of Service Engineer.

Regards Fix

[old gas bottle]

this is busy one, 2k or not 2k !, dont know if i agree with that or not, i tend to work on the understanding that driers need changing periodicley nomater what, if i go to a system thats got a old drier in i change it IF the customer accepts the cost,same goes with filtercores, over the years i have had several problems where driers have broken up,i personaly consider it good practice,i had a brilliant pic on my old phone where the liquid line on top of the drier was full of old black drier internals, when it started up you could hear them jingling up towards the TEV, that system was never any good after that,

[taz24]

I have changed driers for all sorts of reasons and temp differances. The worst was a brazed in dryer that was white over with ice from about half way down its body.

Cheers taz.

[rbartlett]

Two very good points i am in full agreement with.
However neither are in discussion here, what is being questioned is the bizzare generic rule of thumb whereby a drier needs immediate replacement when a 2k temp. drop is found.

A 2k drop can indicate a 40 psig drop. Now why would anyone risk not changing it when they now know. ? This is tantamount to negligence



I do not understand this richard. the colour of the drier is irrelevant. I thought my point was quite clear, but i will explain further.
If a drier is changed because of this 2k temperature differential and the new drier still shows a 2k temperature differential does it need replacing again?
No, clearly it did not need replacing in the first place.

Basically you're making up a question the answering it with 'your' answer and then proclaiming as the truth. However why don't you prove that this isn't true rather than just making something ??

This is very bad practice and considering the cost of a drier shows wanton disregard to the system and customer.




Thank you.
Common sense prevails.

No frankly I would like all those who think it's pointless -9 to date- to come back here and tell us why it's pointless bearing in mind that Lana himself has proclaimed it as true.


I notice also that the poll is starting to prove this point.;)

No what it's proving is that there are another 8 idiots who can't understand principles. They are also lazy in mind and attitude who rather than read and learn are willing to go along with someone else taking the idiots way out.

Sling as a business owner you're very irresponsible and show poor judgement. This forum is partly to educate those within our industry, your attitude reflects badly upon our industry and the standard of education within...

Who ever those 8 are lets see if you are man enough to now admit it here...

Regards


sling.


Sling , you need to raise your game -if only for your customers sake..

Cheers

Richard

[monkey spanners]

If i changed a drier in a system like for like due to a 2k drop and the new one showed a 2k drop also, i'd want to check it was sized for the system correctly and might consider putting a bigger one in. Or i might have dropped my thermometer one too many times:D
I'd change one on a service if its been in for a few years, and i'm ashamed to say wasn't to difficult to get at:o also when the pipeworks been opened, new compressor etc.
Fluke have got a new thermal imaging tester (Ti 20 check it out) that would be ideal for this as it would show the temperature of the inlet pipe, drier, and outlet pipe. But at 4grand i think Dave would have a fit:D
Send off for the free DVD and im sure you will want one also, imagine being able to scan a condeser and see which part is desuperheating and which is condesing and subcooling, scan an evaporator and see if all the circuits are doing equal work, check wireing for loose conections, hang on, the whitecoated guys are back at the door......

[chillin out]

No what it's proving is that there are another 8 idiots who can't understand principles.
I have already said that I change driers when they have to be changed.
If I replace a comp then the drier gets changed.
If there is a perfomance drop in the system and it is traced to the drier then it is changed.
If there is moisture or suspected moisture in the system then the drier gets changed.
If when the system is opened up elsewhere and found to contain debris then drier get replaced.

As a supermarket pack engineer I have to get the job fixed in the least time possible, whether the system is at it's peak perfomance or not is not up to me. Most sites I visit are a complete waste of energy anyway so a dirty drier is of no concequense.
They are also lazy in mind and attitude who rather than read and learn are willing to go along with someone else taking the idiots way out.
I may be "lazy in mind" but my abilities and actions are certainly not.
Reading and learning does not always make the best engineer. You could read all the books in the world and still not fully understand a fridge in real life. You need to have the ability to adapt to every situation, not everything is black and white.

Chillin:) :)

[Temprite]

I change the dryer any time the gas is removed or the system is pumped down to make a repair.

If the system is short of gas and has been operating in a vacuum, dryer and gas get changed.

If the system has problems due to moisture then the dryer gets changed.

If the system isn't operating correctly and the dryer is suspected. I would feel for a temp difference and then perhaps measure the temp across the dryer and change it if required.

I certainly agree that taking temperature readings around a system can be a useful diagnostics tool and I am not disputing the 2K across the dryer.

If people choose to check temperature readings all around the system, check subcool, superheat, discharge temp, low and high side pressures, current draw and whatever other readings they want, thats fine by me. But how the hell do they ever keep up with the volume of work that comes in.

[LRAC]

This thread has a means to kill off members rather quickly, as engineers we decide what course of action to take with driers and this can be learnt or taught.

Make your own minds up how to test driers.Marc O'Brien is correct but whether you follow his teachings is up to YOU.

Lrac

[winfred.dela]

Make your own minds up how to test driers.Marc O'Brien is correct but whether you follow his teachings is up to YOU.


Nice piece of advise, i just vote and keep the decision to myself. :D

Believing the correctness of the advise is one thing, Following it is other one. ;)

As always in life there are no clear cut solutions to everything.


. . . :)