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  1. #1
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    LL Sight Glass Mounting



    What should be the ideal mounting for the Liquid line sight glass - Liquid flowing up or down??



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    Re: LL Sight Glass Mounting

    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
    If the World did not Suck, We would all fall off !

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    Re: LL Sight Glass Mounting

    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 ?

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    Re: LL Sight Glass Mounting

    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

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    Re: LL Sight Glass Mounting

    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
    Mostly found in Oxfordshire, UK :)

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    Re: LL Sight Glass Mounting

    Quote Originally Posted by Grizzly View Post
    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
    Thanx Grizzly

    will have to put you on salary at this rate mate, keep sorting the confusion I leave behind me


    R's chillerman
    Quote Originally Posted by monkey spanners View Post
    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
    Hi Jon / Grizzly

    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
    If the World did not Suck, We would all fall off !

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    Re: LL Sight Glass Mounting

    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
    Mostly found in Oxfordshire, UK :)

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    Re: LL Sight Glass Mounting

    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
    Last edited by simon@parker; 11-10-2011 at 06:42 PM. Reason: grammer
    I can fix broke but I cant fix stupid :)

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    Re: LL Sight Glass Mounting

    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
    If the World did not Suck, We would all fall off !

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    Re: LL Sight Glass Mounting

    What should be the ideal mounting for the Liquid line sight glass - Liquid flowing up or down??
    I think we missed the subject. Again, what is the ideal mounting, liquid flowing from top to bottom OR bottom to top.

    Can there be a scenario of low velocity liquid, flowing anti-gravity and sight glass always seems to be full!!

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    Re: LL Sight Glass Mounting

    Quote Originally Posted by jwasir View Post
    I think we missed the subject. Again, what is the ideal mounting, liquid flowing from top to bottom OR bottom to top.

    Can there be a scenario of low velocity liquid, flowing anti-gravity and sight glass always seems to be full!!
    Hi 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
    If the World did not Suck, We would all fall off !

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    Re: LL Sight Glass Mounting

    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

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    Re: LL Sight Glass Mounting

    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
    If the World did not Suck, We would all fall off !

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    Re: LL Sight Glass Mounting

    Good points yet again.

    Grizzly

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    Re: LL Sight Glass Mounting

    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

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    Re: LL Sight Glass Mounting

    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?

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    Re: LL Sight Glass Mounting

    Gokhan, why do u want to use smaller size?

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    Re: LL Sight Glass Mounting

    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
    Tool's ? check ! Condom's ? check !
    If you can't fix it , f*ck it !!!

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    Re: LL Sight Glass Mounting

    thaks for answers.

    @axelG: because i have a smaller size.

    @stufus: thank for helping.

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    Re: LL Sight Glass Mounting

    @stufus: may i find a video in internet about that??

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    Re: LL Sight Glass Mounting

    Email.jpg

    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.

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    Re: LL Sight Glass Mounting

    Nice one Chemi
    I can't draw for sh1t.
    Cheers
    Stu
    Tool's ? check ! Condom's ? check !
    If you can't fix it , f*ck it !!!

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    Re: LL Sight Glass Mounting

    @chemi-cool; Thank you very much for helping. )

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