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  • – Urgent – Blast Chiller Problems – Urgent –

     fixbear updated 2 years, 3 months ago 1 Member · 52 Posts
  • guest

    Member
    February 22, 2017 at 12:00 am

    Hello Hello! 

     

    This one’s gonna be for all the refrigeration techs out there,

     

    I am running into an issue with my T40 blast chiller, Its giving me the error code “All 14” which means its not getting cold enough fast enough.

     

    This unit has 3 modes, 38* Blast, 38* Hard blast and 0*

     

    From what I observed it will pull the room down to whatever temp you set it for and keep it at that temp, maybe a little below. 

     

    Problem is, there is a problem and its not doing it good enough. I went to the compressor and checked it out, found a leak on the high side service valve which bothered me so i fixed it and then put some refrigerant in until I cleared the sight glass, 

     

    Here’s what I got

     

    Compressor is: 3DB3F33KE-TEC-200 made by Copeland

    Condensing unit is: W075L6-IT3A-3166 made by Trenton

     

    LL: 258 PSI, Liquid pipe temp: 93.6* F

    SCL 12.6*

     

    SL: 12 PSI, Suction pipe temp: 14.3*F

    SH: 40.4*

     

    Then today I went to check it out again and its all different, compressor would shut off and the suction would go into a 8″ vacuum so I adjusted cut in and cut out per Trentons install and service manual and the compressor started short cycling, my suction pressure with the room above 30* would be around 15-16 PSI but as it pulled down, the pressure went down to running about 4 PSI until eventually, the box reached temp and I set the LPCO to kill compressor at about 1 PSI.

     

    I added about 1 lb yesterday, not a lot for a system like this I would think but seemed to clear the SG. I saw bubbles in it again today so I added a couple of ounces and it cleared again.

     

    Having hit the 10-12* SC I would think my solid column of liquid is there so I would need to dial in the SH using the TXV which I started doing and the box hit temp again so I am letting it warm back up and will see what effect it had.

     

    Also, after having the comp run for a little bit the suction line became around -20 F and started frosting on the compressor that was as the box was getting to 0* F and the suction PSI was around 4 or 5.

     

    Any advice would be awesome, I am pretty much on my own and trying to get help from Delfield, Trenton A.K.A Keep Rite and HVAC Talk, I haven’t serviced a blast chiller before nor has anyone I work with.

  • ectofix

    Member
    February 22, 2017 at 6:19 pm

    I have absolutely no experience on that creature…and – I stepped away from serious refrigeration work five years ago.  Our supposed “HVAC” shop does all that (***cough***).  ‘Scuse me…

     

    So, no help from me.  Sorry.

     

    You’ve certainly gotten allot of input about this already.  They can be a bit cruel in their critique(s) and intimidating over there at HVAC-Talk, Olivero.  Been there and done that.

     

    You have the right attitude about it though.  They can EVENTUALLY help you.  Just stick with it.  The solution will hit you when you weren’t expecting it.

     

    Maybe fixbear can chime in.

  • olivero

    Member
    February 22, 2017 at 7:00 pm

    Cool, appreciate the input

     

    They are a bit rough but I do understand them, having to help rookie after rookie after rookie can be a bit annoying, I am sure some guys out there think its all just fun and games and then eventually get hurt or hurt someone, that’s why I sometimes will answer a bit angry or rough, some people just don’t get that it’s serious work.

     

    Either that or they just are like that, either way

  • fixbear

    Member
    February 22, 2017 at 8:54 pm

    You never mentioned the refrigerant in use.Perhaps R404. .  Regardless, the suction line superheat being 40 degrees tells  me the evaporator is starving. Type of metering system? TXV, balanced TXV or cap tube? Being it has a sight glass i’m thinking a balanced TXV. Check the charge and see if it has rusted though and lost it’s charge. The sight glass should be after the dryer, so that’s not the restriction  How long did you let it run after adding refrigerant. It takes 20 min. for the system to stabilize. Seven and 1/2 HP is a lot of compressor for so small a box

       You should also feel the hot gas defrost line near the evaporator to make sure that the valve is not leaking. Once you check those items install temp probe and suction gauge. Open the TXV 1/2 turn and see if it has a effect. It probably won’t , so you will have to replace the charge and chect the liquid screen in the valve inlet..

  • olivero

    Member
    February 22, 2017 at 9:31 pm

    I am just happy you showed up.

     

    Its 404A yes, correct, also TXV yes, correct and yes once again with the SG after the drier, impressive.

    Its also water cooled

    Well, I have been working on it pretty much all day, tricked the door open so it still runs with the door open and now I can mess with the system and see effects.

     

    Looks like it was starved and that was all it was, might be slightly undersized though, opened the TXV, water regulating valve as well as the 2 balancing valves on supply and return are now cranked all the way open and now I am starting see what I want.

     

    Suction pressure is hanging 15-17 PSI, SH is about 20-40* as it pulls down it gets less.

    High side is about 250 with a SC of about 11*

     

    When I started in on this unit I had absolutely no clue about it at all but looks like we are getting somewhere now. Suction pipe is below 32* Pretty much the whole time and after a while will go down below 0- probably in an effort to make that box 36* come hell or high water

     

    well… buddy… it’s not gonna happen when the door is open all the way

     

    IT can go down to 36* and 0* I am doing all this with the unit trying to go to 36* not sure how its gonna all work when it tries to go to 0*, should I worry about that? Chefs use the 36* setting way more than freezing.

     

    after opening the TXV all the way I am seeing bubbles in the SG again, probably added about 2 lbs. on top of the 1 lbs I did the other day. I will weigh it when I am done but just guessing about 2 lbs.

     

    Adjusting the TXV definetley had an effect, brought it from 60* SH to 20*-40* SH.

     

    Gonna turn it back on now that I let it warm back up and see what I got, hopefully its good. So far its improving. *furiously knocking on wood*

  • fixbear

    Member
    February 23, 2017 at 7:57 am

    olivero wrote:

     

    having to help rookie after rookie after rookie can be a bit annoying

    It is our obligation as seasoned tech’s to train and help those starting and even proficient in the trade. .All of us have had that one machine that frustrated us to death.

  • fixbear

    Member
    February 23, 2017 at 8:03 am

    Thank you for telling me it’s water cooled. Now, is it a txv or balanced TXV? Sounds like TXV and that you overrode it so it no longer regulates. Is it a Alco, Sporeland or Danfoss valve? You have to be very careful with this size machine opening the metering as when you add staving refrigerant you can flood back the compressor. That would be like 4 to 5 grand gone.

    Looks like it was starved and that was all it was, might be slightly undersized though, opened the TXV, water regulating valve as well as the 2 balancing valves on supply and return are now cranked all the way open and now I am starting see what I want.

    Where are these at, water side or refrigerant side? Something caused this and you still don’t have the ideal 10 degree superheat. You say that the condenser unit is downstairs, Make sure to visualize the lines the whole way for damage. sometimes workers hit them and crush causing starvation.  If that is all well, change the charge on the valve. be cautious to set the calibration back to where it was before you changed it as you can destroy to compressor. also makes it easier to put the charge on.

     

    As a side note on this one, I had a cooler that was starving like this that drove me crazy. Finally went to change the expansion valve (soldered in) and saw that someone previous had replaced it with soft solder instead of braze. .Now I have to correct by cutting  back due to solder..Can’t do that on the evap due to distributor. It also had a lot of solder glop hanging and in the drain pan. Ok, lets just try rebuilding the valve. Pumped it down and disassembled the valve in place only to find it was full of solder. This cooler could never have worked right from the beginning yet was 6 years old. Just love a AC guy who thinks he can do refrigeration. Can’t tell you how many I’ve been called in to trouble shoot for over the years.

  • olivero

    Member
    February 23, 2017 at 9:59 am

    Yup, water cooled but the location is opposite, Condensing unit is upstaits, chiller is downstairs. 

     

    Its a Alco TXV, TI series. 

     

    Just ran the unit again in freezing mode, took this reading when it was almost at set point of 0*

     

    SP: 5 PSI  Suction pipe temp: -19*F

    SH 15*

     

    LP: 247.2 PSI Liquid Pipe Temp: 90.5*F

    SC: 12.5*

     

    When I ran the unit in cooling mode (36* box temp) yesterday, here is what I got, the unit ran for about 20-30 minutes as I had the door open all the way. Box temp was about 40*

     

    SP: 17.5 PSI          SPT: 11.1*F

    SH: 32.9*

     

    LP: 273 PSI            LPT: 98.7*F

    SC: 11.6*

     

    This looks good to me, What do you think?

  • john

    Member
    February 23, 2017 at 11:09 am

    I lurk over there and really dislike how some folks act. Lots of posts on the web suggest the younger generation is the disrespectful group with a keyboard behind the screen– clearly they haven’t visited over there. 

     

    I’d argue that with great users like you (fixbear, ectofix, olivero, and izzygreen, just to name a few) and our techs here, we rival their knowledge base in commercial kitchen equipment. 

     

    Speaking of, I haven’t seen alnelson or badbozo2315 around here lately. I know bozo is active over there. Any thoughts on that?

  • olivero

    Member
    February 23, 2017 at 11:13 am

    Its true, I do agree.

     

    I think helping the guy next to you out is the responsibility of knowing. Being the guy with the manometer in your hand trying to figure out WHY oh WHUY!!!!!!! this unit won’t do what It’s gotta can bring your understanding of rage to whole new highs

     

    I like teaching what I know, I definetley don’t know a lot, only been in the trade for 3-4 years but I started from scratch with no official training or anything, so I know it can be done.

  • fixbear

    Member
    February 23, 2017 at 11:22 am

    Still wonder why the valve/feed changed.  If the bonding of the bulb was loose it would over feed. I still think the charge has lost some gas. do you see variation in suction temp like the valve is throttling? It should be varying a few degrees as it hunts. If you have the adjustment screwed all the way out, it is not working on the spring. What’s your compressor full load amps and running amps? Tells you if your near capacity.  Something had to change.

     

    How big is the liquid receiver?  Just trying to determine if it could have just been a volume loss that caused it. Water cooled have a very even head pressure compared to air cooled.

     

       Now the big design question.  What is the elevation from the bottom of the evaporator to the suction line on the condenser and the diameter of the tubing. I ask because of oil return.  Milk tank installers were my worst on this.  If you have a high rise one need to place traps every 3 ft to keep the oil returning right. and not choking off the suction. The oil only returns on the tube wall from velocity. Every shut down it drains back to the evaporator without the traps. Makes for a abnormally long equalization.    I imagine this unit must have a suction receiver on it for oil feed and slug protection.

     

    FYO the charge is what opens the feed. the spring closes that you can adjust closes it. The coil back pressure works against the charge that senses the tail coil.  With a bypass TXV a tube is added from the end of the evaporator tail coil to make more accurate sensing and load limiting.

  • olivero

    Member
    February 23, 2017 at 2:01 pm

    Went up to the platform, compressor is half covered in frost, went and grabbed my gauges, hooked in and I had about 3-6 PSI suction, SH was going around from 9-10* SH and the suction pipe temp went all the way to -30* I believe it was.

    That pan of chicken never stood a chance, loaded at 160*F brought it down to -8* in about 90 minutes.

    No error code there. They will be using it a lot this afternoon so I will be perched over the compressor making sure everything runs okay but looks to me like its running good.

     

    With a 9* SH at least I am not flooding it, wouldn’t mind it being a little higher but if I start messing with it, it will affect it when its running on its cooling (38* temp) mode and will put the SH higher.

     

    is 9* SH too low? Trenton’s tech support is saying I am all good and happy but I like multiple opinions.

     

    Got it on the frost, I know its just telling me that my pipe is below freezing and its humid, just never saw it before and was worried I was flooding the compressor.

  • fixbear

    Member
    February 23, 2017 at 2:55 pm

    How certain are you of the calibration of your gauges and temp probe. Was their calibration tested in the last month.  I always keep a low pressure gauge just for testing and regularly check my temp . Have had to replace a few thermocouples. over the years.  If you have a compressor that is covered in frost, you are getting flood back. It’s ok to have a bit of frost on the head and around the suction valve,  but if you are seeing ice farther down the crankcase and near the discharge side you have a problem.  You really need to monitor a machine like this for twenty minutes.  Better yet through a full cycle.

  • olivero

    Member
    February 23, 2017 at 3:15 pm

    Fairly certain, I calibrated them about a month ago.

     

    Its not the entire compressor, only one half of it where the suction is.

     

    If I am getting SH I am not getting a flood back, its 9* above its vaporizing temperature. Again, its a low temp unit, it brings food down to 0* in 4 hours max when its in freezing mode, IT did this pan of chicken to -8 *F in a little less than half that time, now its running in cooling mode and there is not an inch of frost visible on the compressor but the suction line is still below 32*.

     

    Pulling the room that low put that suction line at -20 degrees while its running, 404A at 4 or 5 PSI is about -30 degrees so I am not surprised its frosting, I did have the same concern so I know where you are coming from but after watching it run for 20-40 minutes in freezing mode just sitting on an electrical box watching numbers move and never once did it go below 9* superheat while it was on but the suction pipe temp was slowly going down along with the suction pressure until it hit set point and the chicken was -8 *F. I also asked Trentons tech support who made the condensing unit and he told me its pretty common in Florida for low temp units because there is high humidity.

     

    Here is something on frost and all that.

    Frost And Low-Temp Compressors 

  • fixbear

    Member
    February 23, 2017 at 6:35 pm

    Ah, you never said Florida.. As long as the TXV screw is not deadheaded to one end, you may be ok. I like the superheat and frost on the compressor.  What’s your take down temp?  How much air velocity does this cooler have? 

  • badbozo2315

    Member
    February 23, 2017 at 6:41 pm

    >Speaking of, I haven’t seen alnelson or badbozo2315 around here lately. I know bozo is active over there. Any thoughts on that?

     

    None.  Nope. Zero. 

     

    As some have guessed, I actually work for a PT Holdings sub company, and have been told I need to only post using our company-sanctioned username here, and only in certain forums.

     

    Well, we can see how that’s going. 

     

    Combine that with turning 61 the other day, now counting the days until I can retire, at least somewhat, and give my knees a break.

     

    Also, there is a good group of helpful, knoweldgeable techs at both places, who are more willing to gently guide the young’uns along- as it should be. There’s little need for someone of my calls-em-likes-I-sees-em lambasting of silly-to-stupid shenanigans.

  • fixbear

    Member
    February 23, 2017 at 6:47 pm

    Nice to hear from you young-in!. Tell them to stuff it. free speech. LOL  Unless they supply the comm device.

  • olivero

    Member
    February 23, 2017 at 9:29 pm

    Funny how me mentioning Florida anybody I talk to says “Ah, that explains it”

     

    Yeah, I screwed it in 1 1/4 turn but seemed like it needed to be opened a bit.

     

    Take down temp? Sorry, not familiar with that. I should probably also mention I am from Denmark so some terms may be lost on me, actually, a lot of them are lost on me

     

    Its got 3 fans, its a T40 from Delfield’s Convochill series of garb..*** *cough* sorry… I mean equipment.

  • fixbear

    Member
    February 24, 2017 at 7:20 am

    “Take Down”  is the temperature drop across the evaporator.  Climate in Florida is it’s own thing. Especially the humidity and bugs. That box has to be a costly item to run.  And I’ve never seen a evaporator mounted vertically. How do they control the condensate and refrigerant flow?  Seems to me that refrigerant distribution, flow, especially when undercharged or underfed would be a real nightmare. 

     

    1 and 1/4 turns on a Alco is ok. Sporland, that would be a lot.  You said at one point that you had to bottom the valve. Valve must be under-size for the capacity or you would have flooded it.  Be happy that Delfield run’s on the cheap side.

     

    “Take down” is also important in design for application.  If you where building a floral case, you would design in a 5 degree to keep from drying out the flowers.  Dough retarders would be 5 to 8 degree for the same reason. normal walk ins are 10 to 15 degrees.  As you can see, it’s all about moisture control. With that big compressor and 4 by 5 box the take down has to be enormous.. And once you know it for a cooler,  it’s a fast, cheap, and easy way to check capacity.

     

    Glad your unit runs ok.

  • olivero

    Member
    February 24, 2017 at 8:56 am

    You know, I have no idea how they designed or any of their design specs, I tried to get it from Delfield but they say it’s built in Italy…… I guess that’s a good reason to have no design data?

     

    Its an odd thing, it’s a Delfield unit with a Copeland compressor and a Trenton Condensing unit made for Convotherm’s Convochill series

     

    I had the same thought, since having to open the balancing valves all the way and the water regulating valve were opened all the way. Then the TXV got opened almost all the way, looks like someone undersized it, wonder if its intentional or not.

     

    Is Take down the same as TD?

  • fixbear

    Member
    February 24, 2017 at 9:11 am

    I won’t say undersized, but definitely minimal.  I’m certain cost was the primary as long as if “worked”.  Low temp Copeland is the only reliable solution for compressors. Trentons are one of the least expensive condensers for manufacturers.  .Reliability you by Sporland,  Cost Alco.  That specialized chill evaporator is what I’m interested to learn more about.

     

    Yes TD is take down.

  • olivero

    Member
    February 24, 2017 at 9:53 am

    Yeah, I guess that’s true.

     

    Based on the pressure specs I scraped from Delfield, I think its 10 – 20 TD, Box can pull to 0 Max so the refrigerant is at about -20*F  to -11*F at those pressures.

     

    Then as the box temp drops and suction pressure drops, you end with almost a -40* TD with it at 4 PSI.

     

    Pretty hefty. I think it could be made more efficient though, for some reason, I am not completely satisfied and willing to let it be fixed.

     

    Unit has, soft chill, blast chill and blast freeze. Each one operates their own way, how can you design a system to run efficiently in 3 different ways? Beyond me.

  • john

    Member
    February 24, 2017 at 10:13 am

    badbozo2315

    I did know that since (as admin) I can see your e-mail–and I dig for information.

    Interestingly, I didn’t know you guys were mandated to only post in certain forums. I was hoping the company would say “yeah, use your expertise across the site.” 

    I suppose they’re at odds with giving too much information away. Don’t want to take jobs from the techs (and I truly do not, of course), but we can’t have a working database without users who possess the technical knowledge.

  • fixbear

    Member
    February 24, 2017 at 12:38 pm

    You can’t.  for each working temp change they have to give up something. Delfield is calling the compressor a 6 hp,  but Copeland say’s 7.5. That means that Delfield has found a way to derate it for the wide range.  Is that what you balancing valves are for?  Does this unit have a crankcase regulator valve or suction pressure valve?  They only show a refrigeration schematic for the T15.  Being water cooled they don’t need a head pressure control. Being in Florida it would never need one anyway.  That would also explain the undersized metering.

  • olivero

    Member
    February 24, 2017 at 1:05 pm

    Right, I don’t see how it can ever really run as efficient as possible with the 3 settings all having different TD’s and pull down temps.

     

    Balancing valves are to control head pressure, they control the supply and return of water, not refrigerant.

     

     

    No other valves than the service valve on the suction and liquid side of the compressor, like right off the compressor, not inline.

     

    Not sure what a Crankcase regulator valve is, still kind of new to this cold side of the field.

  • fixbear

    Member
    February 24, 2017 at 1:42 pm

    Makes it so the suction can not go above a set point so that you can have a low temp compressor run a high temp application without overload. They are sweet, to dial in full load without tripping breakers or fuses.  Makes it a method to convert a walk in freezer to a plain walk in.  Also has a tap you can use for a suction pressure control. 

  • olivero

    Member
    February 24, 2017 at 2:43 pm

    Wow, that sounds awesome.

     

    Wonders of the trades, somebody figured it out .

  • fixbear

    Member
    February 24, 2017 at 4:17 pm

    Balancing valves are to control head pressure, they control the supply and return of water, not refrigerant.

    That troubles me.  Do the still have a head pressure water valve to keep it constant?  Without this the ambient and load will make it drift all over the place.  With the water regulating valve the head will stay within 5 lb’s.  They could of  added the bypass for when and if the valve fails.

     

    Supply to the heat ex-changer should be unrestricted and above 30 psi.  It should then go to open drain.  Unless it is being cooled by brown water instead of potable. 

  • olivero

    Member
    February 26, 2017 at 9:43 am

    Yes, there is head pressure water valve as well.

     

    It is brown water circulated, well, with chemical treatment of the loop its more pink than brown.

  • fixbear

    Member
    February 26, 2017 at 12:59 pm

    That explains it. The Valves are to cjhemical clean the system.  Cooling tower or ground sump?

  • olivero

    Member
    February 27, 2017 at 10:17 am

    Neither, direct expansion system with the condenser coil outside with 3 horizontally mounted fans.

     

    The valves only adjust the amount of flow in the pipe, the water is treated to prevent chemical corrosion and whatnot.

  • fixbear

    Member
    February 28, 2017 at 8:07 am

    That would fall under a cooling tower.  Why; Because the heat exchange would still have to have a column of water above it to prevent air entrancement and to allow expansion and replacement of coolant.  A pressure tank can be used for the expansion and minor makeup,  But there still has to be a column above the cooling tubes to vent en-trained air that could impede circulation.   Don’t confuse “cooling tower” with “evaporative cooling tower”.  Different animal that now has to be treated very carefully due to Legionnaires virus. 

  • alnelson

    Member
    February 28, 2017 at 2:56 pm

    Hi

  • alnelson

    Member
    February 28, 2017 at 3:02 pm

    If your condensing unit has a receiver, you don’t need to check subcooling. Since excess liquid refrigerant can stack in the receiver, subcooling doesn’t do much to help determine if you have a full charge or not.

     

    Look for a clear sight glass and check the receiver level to determine if you are low on refrigerant.

     

    When you are adjusting the txv, check superheat on the suction line right at the evaporator.

  • olivero

    Member
    February 28, 2017 at 3:22 pm

    Well, there is some argument on the SC with receiver, been through it before but in theory you can tell if you have sub cooling between the outlet of the condenser to the receiver but after the receiver it won’t be accurate due to the equalization of pressure and temp that can occur in the receiver.

     

    I don’t even think this unit has a liquid receiver despite it being described in the diagram, there are 2 tanks near the compressor, 1 is an oil separator which is on the liquid side and there is what seems like an accumulator on the suction side but could also be an oil separator (wrapped in insulation so I can’t tell). The outlet of the condensing unit that goes to the filter dryer and SG has no receiver on the platform and I doubt they mounted one halfway down.

     

    Oh and get this, they sat the unit on the floor, no legs, no nothing, unit defrosts water gets out the door or someone cleans it and the water gets under it… can’t clean it……………………… could have been installed better IMO.

     

    Sucks for the cleaners, hoping to one day move it somewhere else and have it raised off the floor by at least 5″ per NSF/FDA code.

  • alnelson

    Member
    February 28, 2017 at 3:31 pm

    Oh ok.

     

    The wrapped tank on the suction side is probably an accumulator. 

     

    If no receiver definitely go by subcooling.

     

    Does sound like you got it by adjusting the superheat.

     

    If you have a sight glass with no receiver, the intermittent flashing of the sight glass is probably just from when the txv opens or closes. As long as the glass clears out and you’ve got the correct subcooling it’s all good.

     

    Most txv’s have a screen on the Inlet, sometimes those can plug up and cause high superheat as well.  

  • olivero

    Member
    February 28, 2017 at 3:52 pm

    Okay cool,

     

    I figured it was, don’t understand why the liquid line has no receiver, you would think it would since its load can vary so much.

     

    Yeah SG bubbling and no bubbling is making me think its not low, and I am seeing a good SC so I think I am okay. I think i need to iron out the operators a little to make sure they pick the right type of chilling or freezing depending on the type of food as that will also play a role, unit might think its not getting cold enough but if they pick a soft cooling cycle to cool down roasted pork, it ain’t gonna happen.

     

    I would have to recover all the refrigerant, vacuum and recharge to clean the screen on the inlet?

     

    I have been thinking about this unit for the last couple of days, I would think running 2 separate lines each with its own solenoid would be logical for this unit, 1 would open on the blast cooling and soft cooling cycle and the other would have a receiver and would open on the blast freezing cycle, they would also each have their own TXV so they could be fine tuned for optimum performance.

     

    Right now it’s the same line, same TXV feeding the evap on freezing temps or cooling temps which to me, is not that logical.

     

    I am not an expert in any way, I am actually fairly new to all this fancy schmancy removal of heat systems but to me, that would seem better.

  • alnelson

    Member
    February 28, 2017 at 4:15 pm

    Yes with no receiver there’s no way to pump it down so you would have to recover the charge to clean the txv screen, so probably don’t want to do that unless you absolutely have to. 

     

    Sounds like you’re on the right track. Just need to make sure they set it right and keep the door shut. 

  • olivero

    Member
    February 28, 2017 at 4:25 pm

    Yup Yup.

     

    luckily its got a reed switch on the door so as soon as it opens, unit shuts off, not good for the compressor to flap the door open and closed, they don’t do that but it wouldn’t be good if they did.

     

    Thanks for the input Alnelson.

  • fixbear

    Member
    February 28, 2017 at 9:57 pm

    olivero, It does have a receiver. It is that big shell tube condenser that it sets on.  It holds 56 lbs’s of refrigerant if you are wondering. BTW that condenser is a low temp unit designed to run at a max -5F,  55,000 BTU’s and drop to 25,000 at -40F.  Some other things you might want to know about that condenser. Max water in temp is 80 and out 105.  A shell tube condenser has a tremendous amount of space available volume wise between the outside of the tubes and inside of the shell.  There also is a lot of room between tubes due to the meat needed on the end plates. Normal ones I’ve worked on have three passes for the water

     

    Right now it’s the same line, same TXV feeding the evap on freezing temps or cooling temps which to me, is not that logical.

     

    I am not an expert in any way, I am actually fairly new to all this fancy schmancy removal of heat systems but to me, that would seem better.

    That would put the compressor in overload due to higher suction pressure,/ temp. 

     

        If you follow this linc it will tell you about suction accumulators and show you the inside. http://orders.sidharvey.com/IMAGES/specs/3706.pdf 

     

    I was also surprised to find a Trenton installation and maintenance manual for the T-40 condenser.  Trenton #1068156.  Never seen one nor do I know what it contains. It is active on Trenton parts for that condensing unit. 

  • alnelson

    Member
    March 1, 2017 at 10:48 am

    Yes, good point fixbear, I forgot that the shell/tube condenser is the receiver.

  • fixbear

    Member
    March 1, 2017 at 1:41 pm

    They are a real piece of engineering, but they are prone to leaks due to the tube bundle expanding and contracting. One has to make sure to use their leak detector on the water vent. 

  • olivero

    Member
    March 1, 2017 at 8:39 pm

    Thanks for that Fixbear.

     

    Would have never thought of that.

     

    which part would put the compressor in overload? My idea was to run 2 seperate lines, 1 for cooling, 1 for freezing which is not the case in this moment.

     

    I was just looking at the document you sent me and regarding the suction accumulator and it says it prevents frost and sweat.

     

    The suction service valve on the compressor as well as a good 1/4″ of the compressor builds up frost when the unit is freezing and definetley sweats when its cooling, how can that be if the accumulator prevents that? I have confirmed I have SH so I am not worried about flooding the comp but just curious if there are exceptions.

  • fixbear

    Member
    March 2, 2017 at 5:29 am

    “which part would put the compressor in overload? My idea was to run 2 seperate lines, 1 for cooling, 1 for freezing which is not the case in this moment”.

     

    Your compressor has a very big bore for it’s size and is designed only for low temp. That means suction pressure has to be kept below about 30 psi.  As the pressure rises,  so does the load.  If you use a ammeter on the compressor,  as you adjust the expansion valve or as the load comes down you will see a load change. Other than the starting inrush it should never be over RLA rating.  Remember that start inrush is normally 17 times full load amps. 

     

    Air research makes most of the accumulators and recievers we see. A suction accumulator is primarily used to prevent liquid flood back slug.  As you can see the inlet is below the outlet and faces down. The inlet is at the top and the “U” pipe has a metering hole in the bottom to return oil.  It is a must have if line sets run through a cold area or the evaporator is above the compressor with longer runs.  They also have versions with a tap off for oil tank and make up pump.

     

    I was just looking at the document you sent me and regarding the suction accumulator and it says it prevents frost and sweat.

       It does, if there is some liquid causing it. Your system is at a below zero suction.  Naturally the gas is cold and will carry away heat even though it is light. It still has mass.   Copeland puts the suction on the end of the motor on this unit just to help with that .  The gas has to pass threw the motor,  into the crankcase, and then up into the cylinder.  Frost is expected over the motor area.  One needs to worry if it gets to the crankcase. 

  • badbozo2315

    Member
    March 2, 2017 at 4:12 pm

    I have to say, Mr Bear, while this whole thread has been very informative to this Hot Side guy, your last paragraphs above contain a wealth of information and knowledge right there. Thanks.

  • olivero

    Member
    March 2, 2017 at 9:08 pm

    Thanks Bear.

     

    That makes more sense then, I was thinking with the accumulator there should be no frost so I was worried for a second.

     

    I still think there should be a more effecient way of running it, for the purpose of learning something, why do you think having 2 seperate lines going down is a bad idea? The suction pressure would stay well below 30 in both cases, just SH would be different depending on the application of cooling or freezing.

  • fixbear

    Member
    March 3, 2017 at 7:52 am

    Running two lines would just be a extra. Unless you had a second evaporator.  And even then they could just Tee with solenoid valves.  Trenton is already controlling the temp of the box somehow or they wouldn’t have 3 modes.  One way is to have different evaporator pressure regulators on the tail coil with valves (Dual Pressure valve). Lets the compressor go very low in it’s pressure curve but holds the evaporator at a set temperature and pressure (load). That way the compressor load will self regulate.  With the advent of AC variable speed motor control there are a lot of people trying to use motor modulation.  Primarily on air conditioning right now.  There is also a lot of new electronic TXV’s coming out. But modulating there creates a lot of superheat control and compressor load problems.  One still wants a saturated evaporator for the right capacity.   

     

       I’m certain that someone spent a lot of time designing this chiller.  It  had to be a major pain if the manufacturer and Trenton worked hand and hand on it to the point that Trenton made a service manual special for it.  Perhaps Trenton also made the evaporator?   

  • olivero

    Member
    March 3, 2017 at 8:44 am

    That’s a good point there.

     

    I wouldn’t be too surprised if Trenton made the whole refrigeration enchilada. Seems like Delfield barely has a clue on this unit when it comes to the cold side but they can help you on the electrical side.

     

    They say it’s made in Italy, so it might even be 3 different companies making it. What is that service manual of which you speak? I got the condenser maintenance manual and the blast chillers service manual, is there something else I am missing?

  • fixbear

    Member
    March 3, 2017 at 11:33 am

    Trenton installation and maintenance manual for the T-40 condenser.  Trenton #1068156  

  • john

    Member
    March 3, 2017 at 11:54 am

     fixbear, talking about this?
    http://docs.t-rp.com/1068156.pdf 

  • fixbear

    Member
    March 3, 2017 at 5:08 pm

    The number corresponds, but it’s generic to their condensers. The manual section for look up said for the T40 specifically. under his condenser model.Really would like to talk to the engineer that designed it.

  • rispurge

    Member
    April 27, 2018 at 10:04 pm

    Is this condensing unit inside or outside with a headmaster ? I have seen where a few ounces will clear a site glass and bring a system back to life only to have the outdoor temp drop and unit act up again and bubbles in glass due to an under charged system.

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