What should be the ideal mounting for the Liquid line sight glass - Liquid flowing up or down??
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What should be the ideal mounting for the Liquid line sight glass - Liquid flowing up or down??
None
I dont like sight glasses, other than as a moisture indicator
when fitted some engineers seem to think charge to sightglass and often overcharge
R's chillerman
chillerman, if you do not like the use of sight glass (on the liquid receiver tank?), is there another way of checking the adequacy of ammonia in the system ? our rule of thumb is to assure that at least liquid level on the receiver tank is more or less 1/3 the tank's capacity. this we can only verify thru the liquid level glass gage. if there is another way ?
engrp.
What you describe is a level indicator which may have a sight glass to view the level from.
Which is totally different from a liquid line sight glass.
Which shows the state of the liquid refrigerant within the liquid line at any given time.
What chillerman refers to is, unless all parameters are correct and the "system is fully loaded.
Using a sight glass to indicate a systems charge level is pointless.
Actually if the running parameters are logged correctly a sight glass is totally unnecessary.
Grizzly
I prefer horizontal or upflow but it depends where's easy when your piping stuff up, just don't put them in upside down....
I have systems that have them fitted by the unit and by the evaporator, its not uncommon to see one full and the other bubbly, especially with hfc refrigerants, so i don't pay so much attention to them bubbling now.
Jon :)
Thanx GrizzlyQuote:
Originally Posted by Grizzly
will have to put you on salary at this rate mate, keep sorting the confusion I leave behind me :)
R's chillerman
Hi Jon / GrizzlyQuote:
Originally Posted by monkey spanners
they dont teach that at college or f-gas either do they ?
last week I was pulling out refrigerant after following up 'another'
who I told quite clearly on the phone to charge to sub cooling / not sight glass
sight glass was mounted on side of 5/8 tube via 3/8 stabs
I arrived checked temps/pressures and asked him what he charged to
''I charged to full sight glass & 4.5bar suction''
I explained his error and he said ''but but I could not get the suction pressure to rise and the sight glass was flashing''
I took a deep breath and tried to explain again
he said '' but but you have to have a full sight glass and I was doing my HNC at college but I dropped out as I would never use all the info ''
I took another deeper breath and slowly explained how a system works, whilst watching his head begin to spin...at this point I give up for the day, adjusted the charge faulted a txv and recommended coil cleaning
R's chillerman
You have to remember i grew up working on milk tanks which are just a copper coil in a water jacket, nothing fancy. Back it the day on R12 and old prestcold stuff with propper 5/8" pipe condensers a full sight glass worked great, fast forward to 2011 and R404A and dx tank on copeland 3/8" piped condensers and you will over charge them if you try for a full sight glass.
Who remebers the days with R12 when you'd get a bubble in the sight glass that stayed there and just got samller until it dissapeared as you charged the system? Don't see it anymore and i'm not sure if its either a combination of the blended refrigerants we use now and the cost cutting and material minimising that goes into units.
I never went to fridge college, all i've learn has been for other engineers, books, on here etc.
Jon :)
your sightglass should be after the drier the drier should be verticle refrigerant should flow from top to bottom this was the perfect way for a drier and sightglass to be fitted on a system as it maximised the surface area in contact with the drier at all times the sightglass was there to see if drier was actually blocked not for charging this was told to me by the engineer i did most of my apprentiship with Anthony Susans or tony top bloke what he didnt know you could write on back of a postage stamp hope that helps :)
Hi Jon
Yeah I do mate 20 years ago - R502 R12 R500 and would love the chance
to work on them again and see 'if' I actually got them set up right or not (prob not)
I have been very lucky the last 2 decade's to work with some top engineers who ironed out
some miss-conceptions along with some great minds on Re
am still learning; its those that claim to know it all that worry me most !
even though I have found some 'here' really do, of which a few can be spotted in my friends list
R's chillerman
I think we missed the subject. Again, what is the ideal mounting, liquid flowing from top to bottom OR bottom to top.Quote:
What should be the ideal mounting for the Liquid line sight glass - Liquid flowing up or down??
Can there be a scenario of low velocity liquid, flowing anti-gravity and sight glass always seems to be full!!
Hi jwasirQuote:
Originally Posted by jwasir
mount it anyway that looks the prettiest to you mate, the point I/we are making is dont use the sightglass as an indication of correct charge, just for moisture indication
check your charge by running at fall load and check temps/pressure
95% of all sight glasses I see are mounted horizontaly and the other 5% vertically with flow going up, all done by manufacturers
R's chillerman
Cman.
My income could do with a boost my friend;)
Not correcting just getting to answer first.
Simon.
Good explanation and one I at least, whole heartedly agree with.
If used as an indication of refrigerant flow as you say following the filter drier.
The sight glass serves a useful purpose.
Guru's are great and if you had one you were a lucky apprentice.
MS. If it helps I have friends that hold few formal qualifications.
But it would be a foolish person that questioned their ability or knowledge.
Grizzly
Hi Grizzly
just debating and extracting more thoughts mate
with hfc would agree but these newer blends flash too easily when on the liquid curvature
refrigerants seperate, even a couple of *c subcooled the resistance from the drier appears to
cause this even when the drier is new, so would say when we was taught on hfc's yes 100%
but now with mixed blends does not matter, especially R407c
You would need a considerable drop to overcome this
Your thoughts ???
another part the original poster refers to is anti-gravity/resistance of lift
if we are talking about a few metres up to evap height not much to consider
but if a rise of say 10 x 3 metre floors, 30 metres up to evap height, theres a considerable lift
what effect does this have ???
R's chillerman
Good points yet again.
Grizzly
grizzly/chilerman and all posters, thank you.
sorry and got confused with the LL sight glass. i thought the poster was referring to ammonia systems, but it seems he is not. sorry again, fellow members. as for the sight glass on other refrigerants, particularly, for r134 refrigerants, i just observed that on vehicles we used to work on that used r12, there was a sight glass, while on later model vehicles using r134 system, there is no more sight glass, hence , some of the poster's comments that the wight glass may have a wrong indication of the system charge. referring to the manifold gage readings and actual coldness of the aircon vent, is more reliable. thanks again
hi everybody,
i need help about sight glass.
my liquidline is 2.1/8", but i want to use smaller than 2.1/8 sihgt glass.
Are there any solution abut that?
Gokhan, why do u want to use smaller size?
Use whatever size sight glass you want and stub connect it to your liquid line .But as stated above don't use it for verifying charge best used for moisture indication only.
Cheers
Stu
thaks for answers.
@axelG: because i have a smaller size. :)
@stufus: thank for helping.
@stufus: may i find a video in internet about that??
Attachment 8565
That's the way i use small SG on a larger pipe. The SG can by vertical or horizontal but never under the larger pipe.
Nice one Chemi
I can't draw for sh1t.
Cheers
Stu
@chemi-cool; Thank you very much for helping. :))