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  1. #51
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    Re: 404a high pressure?



    Quote Originally Posted by flyboy3b View Post
    yes,, the evap fan runs all the time,, its my only protection against freeze up.
    Don't worry about freeze up.

    Quote Originally Posted by flyboy3b View Post
    no,, if i moved the sensing bulb for the thermostat to the return air for the evaporator,, i would have to readjust the contacts back close at a higher temp.
    The return air is where the sensing bulb belongs. Why would you have to adjust it?
    Last edited by Gary; 07-12-2007 at 06:12 AM.



  2. #52
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    Re: 404a high pressure?

    Hmmmm... I'm trying to get a mental picture of this system. Apparently you installed an oversized condensing unit. Assuming the airflow is pull through, and we know the airflow exits the front, then the condenser coil must be sticking out the back. And you have it buried in the wall?... so it's getting restricted airflow, but the air is really cold because it is winter. Does that about describe it?

    Please tell me I'm wrong and the condenser is not inside the wall.
    Last edited by Gary; 07-12-2007 at 06:14 AM.

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    Re: 404a high pressure?

    hi Sir flyboy3b,your thread looks interesting and educational i had a great time reading and thanks to Sir gary for such overwhelming exchanging of professional ideas i may say

    i am working here in the middle east where ambient temp varies from time to time especially now a days,where it is getting colder,but not as colder than in US,

    as young compare to you guys ,LOL,i just encouraged myself to ask question about your thread's query

    your Box temp=43f is desirable to you as application call's for it ,in these temp what really problem's you Sir,i mean is/are other components of the system affected,i mean those visible undesirable symptoms like frosting.

    thank you very much
    Last edited by cristopher_uy; 07-12-2007 at 07:45 AM. Reason: spelling corrections

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    Re: 404a high pressure?

    the reason for asking is that,it seems your desired room temp is quitely near to the point u wanted but
    still problems you

    hope your scrap designed system will soon works well.

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    Re: 404a high pressure?

    Okay... here's where we are at this point:

    The thermostat sensing bulb should be sensing the return air.

    The condenser should be at least 3 inches from the wall. If this means you have to move the ice machine, then move the ice machine.

    The unit isn't running long enough to get good readings, apparently because you are concerned about frosting the coil.

    The suction pressures are going to run low and the coil is going to frost, because the condensing unit is oversized. Not to worry, it will melt during the off cycle.

    Place a glass of water in the middle of the box and stick a thermometer in it. This will tell you the actual product temperature and then you can ignore the box temperature, which seems to be close to the evap air out temp for some reason.

    Are we making any progress this morning?
    Last edited by Gary; 07-12-2007 at 05:25 PM.

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    Re: 404a high pressure?

    BTW, I can understand saving money by doing the job yourself. What I can't understand is using junk parts, which are not even designed for this type of system, from the surplus store. Get a real thermostat.

    There is a time to be tight and a time to be right.
    Last edited by Gary; 07-12-2007 at 06:26 PM.

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    Re: 404a high pressure?

    I Am Sure That The Unit Tev Is Too Small And There Is Far Too Much Gas In That System.
    Check The Sub-cooling And Check The Superheat!change The System To Cap Tube!!!
    325 Psi At 70f.you Will Murder That Compressor If That Ambient Temp Goes Up!too Much Gas Backing Up In The Condenser.

  8. #58
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    Re: 404a high pressure?

    it looks like i wont be able to get those readings till tues or wed. me and my girlfriend are heading out for a couple days,, just to get out of town,, maybe sit in a hot tub for a while,, have a nice dinner or two,, and try to warm up.

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    Re: 404a high pressure?

    Quote Originally Posted by Gary View Post
    Hmmmm... I'm trying to get a mental picture of this system. Apparently you installed an oversized condensing unit. Assuming the airflow is pull through, and we know the airflow exits the front, then the condenser coil must be sticking out the back. And you have it buried in the wall?... so it's getting restricted airflow, but the air is really cold because it is winter. Does that about describe it?

    Please tell me I'm wrong and the condenser is not inside the wall.
    the condenser is 2" from the wall, and i also opened up the wall to give it some extra space and yes,, the condensing unit is oversized, but at the time i needed to get it running and thats all i had on hand to get it working. at some point when i have more time,, i will reinstall the old system with a cap tube.
    remember,, i have never built a system from scratch before,, so i just went with what i knew (or thought i knew) and it has been a good learning experience for me.

    as far as the thermostat goes,, its not a "cheap" thermostat,, i just didnt pay alot of money for it. its a ranco thermostat and it is adjustable. give me a few days and ill go in and move the sensor bulb and adjust the differential down.

    markacs,, the txv is a 1/4 ton and it should be plenty big for a little box like this,, but i agree,, it should be a cap tube system. it started out as a cap tube systm.
    thanks for all the input,, ill see you folks in a few days,
    mike

  10. #60
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    Re: 404a high pressure?

    I'm sorry but as 404a is a blend of refrigerants you cannot charge to a full sight glass, due to the fact that some vapor is always going to be present. This is quoted from Althouse. Turnquist, et. al., and also known from experience.

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    Re: 404a high pressure?

    hi honey, im hooome,

    man,, we ended up driving back through that ice storm yesterday. it wasnt as bad in wisconsin as it was elsewhere, but it sure was slippery, and the snowflakes in milwaukee were 2" wide. crazy stuff.

    so,, here is where we are today.
    i moved the thermostat bulb to the inlet of the evap coil and adjusted the thermostat. these are the current readings (taken before i moved the thermostat)

    ambient 74f
    box temp 47f
    cond air in 74f
    cond air out 90f
    evap air in 56f
    evap air out 42f
    suc after the evap coil 53f
    suc at compressor 62f
    liquid at receiver 98f
    pressures 52/278 psig

    ive included a couple of pictures (if they arent too large to post) so you can get an idea of what this thing looks like. if i could ask a favor,,, gary,,,, would you apply your magic formula to these measurements and post the results?

    ok,, the pictures were too large,, so i posted them to my website,, and i will try to include the link here,,,
    http://wavespub.com/cooler.html
    lets hope this works,
    thanks again
    mike

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    Re: 404a high pressure?

    Wait until the evap air in is 40F or less, then take measurements. If the unit shuts off before the evap air in gets below 40F, then the thermostat isn't set low enough.

    BTW, I don't think you could pick a worse location for that condenser. Judging by the picture, its a wonder that it gets any airflow at all.
    Last edited by Gary; 12-12-2007 at 09:48 PM.

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    Re: 404a high pressure?

    i dont think the evaporater return air will ever get that low,, but what the heck,, i have time. maybe next monday when no one is going in there.

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    Re: 404a high pressure?

    and yes,, i agree,, the condenser coil is in a bad place,, but ill make sure it gets the air it needs. the restaurant is very small and there is no basement. you would be shaking your head even more if you knew where all my remote condensing units were and how i keep them cool.

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    Re: 404a high pressure?

    I take it the thermostat is located inside the box? The thermostat can be located anywhere that's convenient, as long as its sensing bulb is located in the return air. For example, you might want to locate it in the machine compartment on the outside of the evap cover plate.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    and yes,, i agree,, the condenser coil is in a bad place,, but ill make sure it gets the air it needs. the restaurant is very small and there is no basement. you would be shaking your head even more if you knew where all my remote condensing units were and how i keep them cool.
    I've been shaking my head for forty years. Nothing surprises me anymore. Let me guess: They are in a crawl space under the building, sitting in the mud... or maybe up in the attic, roasting in the summer and getting a hernia from the head pressure. Been there, done that.

    You might consider turning the entire condensing unit 180 degrees. Room air would enter the condenser from the bottom of the opening and the heated air would then rise and exit out the top of the opening back out into the room.

    I hope you aren't planning to put a door on that opening. You would have the hot air recirculating.
    Last edited by Gary; 12-12-2007 at 11:21 PM.

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    Re: 404a high pressure?

    if you look closely at picture of the right side,, you will see and electrical box with some yellow wirenuts sticking out. along the edge of that junction box, in the middle, you will see a brass knob. that is the thermostat.

    all the pipe connections are on that end of the condensing unit,, turning it around would be a real nightmare to install or repair, but its a nice idea.
    ideally,, i would have one or two remote units in the basement, and just pipe everything from there,, but its not possible

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    ambient 74f
    box temp 47f
    cond air in 74f
    cond air out 90f
    evap air in 56f
    evap air out 42f
    suc after the evap coil 53f
    suc at compressor 62f
    liquid at receiver 98f
    pressures 52/278 psig
    52psi = 17F
    278psi = 112F

    112 - 74 = 38F TD. This shows a very heavy load OR non-condensables. I believe it is heavy load because the subcooling is not excessive (112 - 98 = 14F subcooling), but I could be wrong.

    We can check for non-condensables by pumping down the unit and comparing the high side pressure to the temperature of the condenser.

    Close (front seat) the receiver outlet valve. When the low side pressure reaches around zero psi, shut off the unit. Let it sit for about 15 minutes, then measure the temperature of the condenser. Insert your temperature probe between the fins near the center of the condenser.

    We will need to know both the condenser temperature and the high side pressure.

    BTW, do you have a pressure/temperature chart? They give them away at refrigeration supply houses everywhere.

    Or here is an online chart:

    http://www.parker.com/rs/PDFS/Ref_Temp_Chart.pdf
    Last edited by Gary; 13-12-2007 at 04:56 PM.

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    Re: 404a high pressure?

    ill do the pump-down thing tomorrow morning. i havent taken any temps down there,, but it looks like the box temp has dropped to the low 40s.

    i would be surprized if there was any non-condensibles in there as i pulled it down to a 500 micron vacuum last time and the system itself has never run into a vacuum, but what the heck,,, it cant hurt to look.

    and yes,, i grabbed a bunch of those little charts. handy little devils. i wonder if i can find a software for that to put on my cell phone?

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    Re: 404a high pressure?

    its me again,,,

    i took these readings before i pumped it down,,,

    amb 79f (this number can be misleading because at the time, both the ice machine and wine cooler were on. if you took the reading from the middle of the room,, it would be closer to 70f)
    box temp 44f
    evap in 52f
    evap out 37f
    cond in 70f
    cond out 90f
    suc line after evap 44
    suc line before comp 56f
    liq line at receiver 100f
    pressures 45/280 psig

    i closed off the receiver valve and it pumped the low side down to 0 psig in less than a minute. i shut the cooler off and waited for about 25 mins. at that time the temp in the cond coil was 66f and the pressure was 180psig. now i know what you might be thinking,,,,,, 66f would indicate a pressure of 138 psig for 404a,,, quite a difference from 180 psig. and im not saying that it would be impossible for there to be non condensibles in the system, but,,,,,, the temperature at the cond coil may be reading falsely wrong because when everything is off,, the adjacent (outside brick) wall would bring that temp down fast. the compressor was still warm (maybe 90f) so maybe the true temperature is somewhere in between those numbers. the low side pressure remained at 0 psig the whole time.

    one question i would have is,,,,, if i somehow fractionated the refrigerant when i put it in,, how much of a pressure difference could i expect to see. i was unable to find a P/T chart for 143a or hfc 125 (the major components of 404a).

    anyhow,,, thats where we are.
    thanks,
    mike

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    Re: 404a high pressure?

    flyboy3b
    1]your design is aircooled chiller.
    2]insufficient subcooling @ condenser.
    3]wrongly select xpansion valve

    if you look into the above you'll have better cooler box.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    i closed off the receiver valve and it pumped the low side down to 0 psig in less than a minute. i shut the cooler off and waited for about 25 mins. at that time the temp in the cond coil was 66f and the pressure was 180psig. now i know what you might be thinking,,,,,, 66f would indicate a pressure of 138 psig for 404a,,, quite a difference from 180 psig. and im not saying that it would be impossible for there to be non condensibles in the system, but,,,,,, the temperature at the cond coil may be reading falsely wrong because when everything is off,, the adjacent (outside brick) wall would bring that temp down fast. the compressor was still warm (maybe 90f) so maybe the true temperature is somewhere in between those numbers. the low side pressure remained at 0 psig the whole time.
    Another possibility is that your gauge is off by about 40psi, although that seems highly unlikely. Just to make sure, hook your gauge up to your refrigerant jug. The pressure should correspond to the temp of the jug.

    Most likely you have air in the system and you will need to evacuate it again. Did you evacuate from both sides? Did it hold vacuum?
    Last edited by Gary; 15-12-2007 at 07:45 AM.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    the temperature at the cond coil may be reading falsely wrong because when everything is off,, the adjacent (outside brick) wall would bring that temp down fast.
    You might try placing a piece of cardboard between the condenser and the wall to block the cold air, then check temp and pressure.

    Or better yet, measure the temp on the drip leg (the line between the condenser and the receiver).
    Last edited by Gary; 15-12-2007 at 02:09 PM.

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    Re: 404a high pressure?

    i dont actually recall if i pulled a vacuum from both sides or not, but its such a small system,, do you think it would matter?

    i held the vacuum for about 10 minutes at 500 microns, i even tapped the side of the compressor,, just in case. but it is a new system,, and i have leak-checked it a couple of times. but like i said before,, the system has never run into a vacuum, so if it were leaking,, the pressure would be dropping (instead of sucking air).

    my bottle of 404a is sitting outside, and its cold out,, but i should be able to check my guages with it. i have several other guages to try as well,, but these are the newest.

    hendry, i appreciate your input. yes,, its an air cooled wine chiller and i agree,, i could use some more air across the condenser coil. at a point,, im going to have to live with a less-than-efficeint cooler, because that is the only location it can go (its a very small place). the txv, however, is a 1/4 ton, 404a txv. it should be plenty big for this small box.

    anyhow,, ill post the latest results later tonight or tomorrow morning.
    thanks again,
    mike

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    Re: 404a high pressure?

    ok,, heres the deal,,,

    it would appear that gary is much smarter than he looks (just kidding gary).
    i checked my gauges against my bottle of 404a i brought in from outside. it is 26f and my high side gauge read 150 psi. well,, thats not right. so i checked the low side gauge and it read 65 psi. that sounds more like it.

    i purged the gauge set and retook the readings and both sides measured about the same (correct) pressure .

    i double checked this against my bottle of 134a and both sides measured correctly

    what do i gather from this? is the lossless fitting not letting the gas back out of the high side fitting? is there something in the high side of the gauge set thats not letting the pressure equalize? is this normal for a REFCO set of gauges or are they broke. this wine cooler is the only system ive worked on in the last week,, so i had no reason to purge the gauge set each time i used it. and why does the low side equalize properly each time? the fittings are the same and they are all brand new.

    thanks again gary for your sage and intuitive advice.
    mike

    ps,, i will retake the readings tomorrow when the restaurant is closed

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    i dont actually recall if i pulled a vacuum from both sides or not, but its such a small system,, do you think it would matter?

    i held the vacuum for about 10 minutes at 500 microns, i even tapped the side of the compressor,, just in case. but it is a new system,, and i have leak-checked it a couple of times. but like i said before,, the system has never run into a vacuum, so if it were leaking,, the pressure would be dropping (instead of sucking air).

    my bottle of 404a is sitting outside, and its cold out,, but i should be able to check my guages with it. i have several other guages to try as well,, but these are the newest.

    hendry, i appreciate your input. yes,, its an air cooled wine chiller and i agree,, i could use some more air across the condenser coil. at a point,, im going to have to live with a less-than-efficeint cooler, because that is the only location it can go (its a very small place). the txv, however, is a 1/4 ton, 404a txv. it should be plenty big for this small box.

    anyhow,, ill post the latest results later tonight or tomorrow morning.
    thanks again,
    mike
    [QUOTE][/QUOTE

    thank you to you, too!

    you know ... you could modify the condenser to be more efficient with current constraints.

    i've done it for my clients.

    it became a hybrid condenser. you know what?
    lesser condensing pressure/temp & better performance.

    worth trying if you are in for better system.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    it would appear that gary is much smarter than he looks (just kidding gary).
    I'm not as stupid as I look... nobody is... lol

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    Re: 404a high pressure?

    here we are again,, and here are the current readings.

    ambient 75f
    box temp 39f
    evap air in 50f
    evap air out 41f
    cond air in 68
    cond air out 81f
    suction line at txv 52f
    suction line at comp 68f
    liquid line at receiver 91f
    i closed the receiver valve and pumped down the system and the temp at the condenser was 80f and pressure was 190 psig which is about 15 lbs high,, but that may have balanced out had i waited a bit longer.
    when i took these readings the pressures in the system were 55/200 and i suspect a small leak. i leaked checked it again and found no leaks,, but i have not checked either of the coils. next monday
    i will recheck the pressures and leak test the other parts if needed. in the meantime,, i topped it off with a couple of ounces of 404a.

    hendry,, what modifications are you reccomending?

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    Re: 404a high pressure?

    I do a mostly reataurants and if you're chilling fancy wines then the mean temp is around the low 50's. I've done several cases that have heater to bring the temp up.
    as for 404a, I used to do a lot of Wendy's. they used hobart reach in freezers for french fries. My job was to go behind the other guys reluctantly doing food service(HVAC guys who thought they were too good) I had a unit this guy worked on that had 2 9' cap tubes he replaced then walked away without checking. unit running low pressures. I pressurized to 125psig with nitro and leak checke. pressure held the entire time. weight the charge in and still low pressure. called the factory about the caps. they were correct. factory tech said if the unit was in an area with an ambient temp higher than 78 then the oil seperates from the refrige and coats the inside of the evap. the unit was next to the fryers. I added a couple ozs and temp dropped. they make a flush I have used on other fry freezers since.

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    Re: 404a high pressure?

    Quote Originally Posted by Chicharronne View Post
    factory tech said if the unit was in an area with an ambient temp higher than 78 then the oil seperates from the refrige and coats the inside of the evap. the unit was next to the fryers. I added a couple ozs and temp dropped. they make a flush I have used on other fry freezers since.
    i am aware of the oil problem,, i dont think the temp has been high enough for that to happen,, plus the fact that it is a new system. but i will keep it in mind as a possible problem. i keep the temp down in the wine cooler partly because people are in and out of it all day and the temp rises fast.
    thanks,
    mike

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    here we are again,, and here are the current readings.

    ambient 75f
    box temp 39f
    evap air in 50f
    evap air out 41f
    cond air in 68
    cond air out 81f
    suction line at txv 52f
    suction line at comp 68f
    liquid line at receiver 91f

    when i took these readings the pressures in the system were 55/200
    55 = 19F
    200 = 89F

    Well... that changes everything... and it explains everything.

    89 - 68 = 21F TD

    Light load... and we can forget about non-condensables.

    52 - 19 = 33F superheat

    89 - 91 = -2F subcooling

    You have low subcooling (not enough refrigerant in the high side) with high superheat (not enough refrigerant in the low side). That combination tells us the system is undercharged. Add refrigerant until the subcooling is 10-15F. Then we will see some very different readings. It helps to have accurate gauges.
    Last edited by Gary; 19-12-2007 at 03:57 PM.

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    Re: 404a high pressure?

    lol

    ill try to check the subcooling this aft,, otherwise in the am

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    i keep the temp down in the wine cooler partly because people are in and out of it all day and the temp rises fast.
    Right now it is working reasonably well despite being grossly undercharged with a maladjusted TXV. Once we get this thing working right, you will be able to set the temp wherever you want and it will hold no matter how often people are in and out of it. The TXV will give you very fast recovery. That's what a TXV does best.
    Last edited by Gary; 19-12-2007 at 05:03 PM.

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    Re: 404a high pressure?

    well,,, there is trouble in paradise.

    the system has a small leak,, and im not sure where it is. ive leak tested everything accessible and no luck. itll probably be monday before i can get at the 2 coils.

    when i went to adjust the subcooling i noticed the box temp had climbed to 52f, so i checked it over and decided to just pump it down and start over. after evacuating the system i hooked up my vacuum pump and started pumping it down. the vacuum gauge hovered between 400 and 700 microns. when i disconnected the hose going to the cooler,, it promptly came down to 200 microns and when i hooked it back up,, it jumped back to 700 microns. so that rules out the hoses, fittings, vacuum gauge and vacuum pump.
    anyhow,, i hope its in the evaporator,,, its much more accessible.

    on a different matter,, i asked this question on another thread,, but im still not exactly clear on this,,,
    with a standard recovery tank with a liquid port and vapor port,, does the liquid port reach into the bottom of the tank? in other words,, if i want to get liquid to come out,, do i leave the bottle upright and use the liquid port,, or do i invert the bottle and use the liquid port.
    sorry if this is a stupid question,, but ive never seen the insde of one of those tanks.

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    Re: 404a high pressure?

    or can i invert the bottle and use the vapor port?

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    Re: 404a high pressure?

    Yes, from the liquid port is a dip tube to the bottom of the bottle.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    well,,, there is trouble in paradise.

    the system has a small leak,, and im not sure where it is. ive leak tested everything accessible and no luck. itll probably be monday before i can get at the 2 coils.

    when i went to adjust the subcooling i noticed the box temp had climbed to 52f, so i checked it over and decided to just pump it down and start over. after evacuating the system i hooked up my vacuum pump and started pumping it down. the vacuum gauge hovered between 400 and 700 microns. when i disconnected the hose going to the cooler,, it promptly came down to 200 microns and when i hooked it back up,, it jumped back to 700 microns.
    That doesn't mean you have a leak. It means you didn't leave the pump on long enough. Refrigerant is absorbed into the oil in the compressor. When you shut it down, some of that refrigerant escaped from the oil and brought up the pressure. The question is, after it came up to 700 microns, did it stay there or did it continue to rise? A leak doesn't stop rising until it reaches zero psi.

    Quote Originally Posted by flyboy3b View Post
    on a different matter,, i asked this question on another thread,, but im still not exactly clear on this,,,
    with a standard recovery tank with a liquid port and vapor port,, does the liquid port reach into the bottom of the tank? in other words,, if i want to get liquid to come out,, do i leave the bottle upright and use the liquid port...
    Yes.
    Last edited by Gary; 19-12-2007 at 08:03 PM.

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    Re: 404a high pressure?

    Hmmm... I don't understand why you decided to evacuate it and start over?

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    Re: 404a high pressure?

    gary,, i had considered that,,, or the possibility of moisture in the system, but this system is so small. i figured it would have balanced out over a period of 20 or 30 minutes. also considering the rise in box temp (which it had been holding fairly well) and the drop in pressure. it just seems the most likely answer.

    monday,, possibly sooner,, i will retake the reading and see where we are at

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    Re: 404a high pressure?

    i left it at 700 microns for 10 minutes.

    when i had the vacuum pump hooked up,, it would hit 400 microns,, and then slowly drift back up to 700,, then back down and up again. isnt it possibly to have a leak so small that it would only leak under extreme vacuum or pressure?
    in either case,, i figured it wouldnt hurt to rule out any chance of fractionation or noncondensables.

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    Re: 404a high pressure?

    I have seen nothing remotely indicating a leak. What this system needs is to be charged up to 10-15F subcooling.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    i left it at 700 microns for 10 minutes.

    when i had the vacuum pump hooked up,, it would hit 400 microns,, and then slowly drift back up to 700,, then back down and up again. isnt it possibly to have a leak so small that it would only leak under extreme vacuum or pressure?
    No, it isn't. What you are seeing is refrigerant escaping from the oil.
    Last edited by Gary; 19-12-2007 at 07:46 PM.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    isnt it possibly to have a leak so small that it would only leak under extreme vacuum or pressure?
    Perfect vacuum is something less than -15psi. If it leaks under extreme vacuum, then it will leak at 15psi positive pressure. There is nothing extreme about it.
    Last edited by Gary; 19-12-2007 at 08:15 PM.

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    Re: 404a high pressure?

    and you are probably correct,, but what about the sharp drop in pressure and rise in box temp. it was 39f yesterday,, and 52f today,, and the high side presure was down to 200psig

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    and you are probably correct,, but what about the sharp drop in pressure and rise in box temp. it was 39f yesterday,, and 52f today,, and the high side presure was down to 200psig
    The high side pressure was probably around 200psi all along, but the gauge was not accurate. There is something wrong with that lossless hose fitting.

    I can't see the system from here. I can only evaluate it from your measurements, so those measurements need to be accurate... or at least in the ballpark.

    The box temp isn't going to tell us anything until we get the right amount of refrigerant into the system... and even then I would go with the glass of water with a thermometer in it. We don't care what the box temp is, we care what the wine temp is... and I'm betting that the wine temp is closer to evap air in temp than it is to box temp.
    Last edited by Gary; 19-12-2007 at 09:40 PM.

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    Re: 404a high pressure?

    Quote Originally Posted by Gary View Post
    and even then I would go with the glass of water with a thermometer in it. We don't care what the box temp is, we care what the wine temp is.
    since you said that, ive been taking the temp of an open bottle of wine from the cooler,, so that part was accurate.
    as far as the gauges are concerned, i have been making sure to purge them before taking the readings for the last couple of days, so i believe the readings to be accurate.

    im not saying im right, but what else could account for such a large increase in box temperature. it had all night to reach temp and i had the thermostat set to its coldest setting (yesterday, when i looked in the cooler,, i had noticed the temp had gone up a bit, so i turned down the thermostat). the wine was at 39f the last time i checked it,, and this morning it was 52f. and the temp has been dropping since i filled it.

    i guess we'll know more tomorrow.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    since you said that, ive been taking the temp of an open bottle of wine from the cooler,, so that part was accurate.
    as far as the gauges are concerned, i have been making sure to purge them before taking the readings for the last couple of days, so i believe the readings to be accurate.

    im not saying im right, but what else could account for such a large increase in box temperature.
    Not enough refrigerant in the system.

    I haven't been telling you to add refrigerant because the high side pressure (and therefore the subcooling) has been erroneously saying that it didn't need it.

    Quote Originally Posted by flyboy3b View Post
    it had all night to reach temp and i had the thermostat set to its coldest setting (yesterday, when i looked in the cooler,, i had noticed the temp had gone up a bit, so i turned down the thermostat). the wine was at 39f the last time i checked it,, and this morning it was 52f. and the temp has been dropping since i filled it.
    What are the subcooling and superheat temperatures, now that you have filled it?
    Last edited by Gary; 19-12-2007 at 10:12 PM.

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    Re: 404a high pressure?

    Quote Originally Posted by flyboy3b View Post
    as far as the gauges are concerned, i have been making sure to purge them before taking the readings for the last couple of days, so i believe the readings to be accurate.
    It occurs to me that lossless hose fittings are designed to be used on schrader type valves. If the high side access is not a schrader valve, then the hose won't work properly. If this is the case, switch to a standard hose.
    Last edited by Gary; 20-12-2007 at 08:00 AM.

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    Re: 404a high pressure?

    i can disconnect the lossless fittings,, no biggy there,, itll be tomorrow before i can take any more measurements (me and my sweetie had a little too much rum last night and i overslept).

    ps,, i know its hard to try to diagnose a system just by reading all my mispelled words (did i mispell mispelled? it looks funny) anyhow,, i appreciate your time,
    thanks,
    mike

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    Re: 404a high pressure?

    i took some more readings this morning,,,

    ambient 74f
    box 45f
    cond in 72f
    cond out 87f
    liq line at receiver 94f
    suc line at bulb 41f
    evap air in 54f
    evap air out 44f
    pressures at 35/250 psig

    subcooling is 10f
    superheat is 27f

    the coil had started to ice up (i had the thermostat set to low) so i shut it down for 15 mins and restarted. at that point the pressures were 50/250 psig. ill check it again tomorrow am,, or sunday am.

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