Ice in TXVs
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Thread: Ice in TXVs

  1. #1
    Join Date
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    Ice in TXVs

    Ok so I'm new and I'm not a tech...but reading a post below made me want to ask a question. Bear with me as I'm learning and sometimes my trade vocab isn't the best...

    So at the market I work at we have one rack with split suction, the low temp "part" of it is serving some glass door cases, the the medium temp part (it has an epr) is serving a small walk in and 2 multideck beer displays. Last week I wanted to transfer refrigerant from this rack (let's call it Rack A) to another rack (rack D). Rack A's average liquid level as measured at the reciever averaged 85%, whereas the other rack had a leak (which was repaired) and the liquid level only measured 30%. Rack D has a very high load as well, lots of cases on it compared to all the other racks. So, the journeyman that I work with wanted me to find a liquid line service port on Rack A, and a suction line service port on rack D as close together as possible (he only had 75' of hose). Long story short, when I was looking for the liquid line schrader valve in the glass door cases, I noticed a huge ball of ice around the liquid line just after the TXV. The same day, I noticed the site glass for the same rack was black. So, talked witht he journeyman and he replaced the filter drier core and sightglass. Told him about the other problem (I thought it was a TXV that needed to be adjusted! Dumb!) and he said no, probably ice in the txv (this sort of txv doesn't have the removable screen). So now I'm going to put hot water on the ice ball and txv in hopes of melting the ice within the txv. My question is...if I succeed in clearing the txv of ice (internally) that water has to go somewhere, right? The journeyman I work with told me to buy a high water filter/drier core (RCW-48). Will it be able to strain out the tiny amount of water that must be blocking the txv? And I'm sure all the txvs in the glass door cases have the same problem....in other words, if I de-ice all of them, am I going to create a problem somewhere else in the rack, or will the new filter drier core be able to handle it?

  2. #2
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    First off, I would continue learning from and asking questions of your journeyman. One of the surest ways to know if the txv is working correctly is to check the superheat. If you have a moisture contaminated rack there are several steps you will need to take.
    Supermarket Tech...and anything else the boss finds for me!

  3. #3
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    Maybe I'm confused, but ice on the outlet of the TXV at the distributor has nothing to do with moisture freezing inside the TXV itself. If you had moisture inside the valve it would not feed much or any refrigerant to the evap coil and the box would warm up. Check your superheat to determine if it's feeding correctly. If it is, then don't worry about the ice on the pipe. As far as the black sightglass, it could be carbon in the system. The filter/drier core should catch most of that. You may need to replace the glass.

    Ice at the distributor is very normal, especially if you have electric defrost.

    A bit off topic, bit just last week I got a call from a local market where a guy took a hammer and chisel to a frosty distributor. Nice pinhole and hairline crack in the pipe was the result, along with a very large R-404a leak. That cost 'em some $$$. Luckily for me the pipe was right out in the open.

  4. #4
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    Quote Originally Posted by man from trane View Post
    Maybe I'm confused, but ice on the outlet of the TXV at the distributor has nothing to do with moisture freezing inside the TXV itself. .
    My understanding is that if moisture is in the system, it can freeze inside the txv, blocking it and causing the refrigerant to vaporize *just after* the txv, rather than in the middle of the coil. Several refrigeration mechanics have told me the same thing...I have even seen them pour hot water on the txv (or use a heat gun) and it's always worked. Well, not always...60% of the time. The times it didn't work the txv needed to be adjusted.

    Checking superheat is totally logical and I should have thought of it! Unfortunately I can't use my guages as I'm not certified yet. Hopefully that will change next week.

  5. #5
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    You can't use your gauges because you're not certified by whom? We have guys using gauges here one day and pouring concrete the next. They're not certified to mow grass let alone do refrigeration work. But if that's the rules where you live, that's probably a good thing.

    You're correct about ice freezing at the outlet of the TXV and restricting flow. I was only trying to say that ice buildup on the outside of the pipe doesn't necessarily mean it's freezing on the inside.

  6. #6
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    Saint Augustine, Florida, United States
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    Quote Originally Posted by man from trane View Post
    Maybe I'm confused, but ice on the outlet of the TXV at the distributor has nothing to do with moisture freezing inside the TXV itself. If you had moisture inside the valve it would not feed much or any refrigerant to the evap coil and the box would warm up. Check your superheat to determine if it's feeding correctly. If it is, then don't worry about the ice on the pipe. As far as the black sightglass, it could be carbon in the system. The filter/drier core should catch most of that. You may need to replace the glass.

    Ice at the distributor is very normal, especially if you have electric defrost.

    A bit off topic, bit just last week I got a call from a local market where a guy took a hammer and chisel to a frosty distributor. Nice pinhole and hairline crack in the pipe was the result, along with a very large R-404a leak. That cost 'em some $$$. Luckily for me the pipe was right out in the open.
    What? He chiseled the ice off? I guess he didn't want to waste that expensive water ya'll have down there. What island were you on?

  7. #7
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    Quote Originally Posted by JWB View Post
    What? He chiseled the ice off? I guess he didn't want to waste that expensive water ya'll have down there. What island were you on?
    The store owner told him to pick up any chunks of ice on the floor and the guy went a little too far. My repair and 15 lbs. of R-404a cost about as much as two truckloads of water. Poor guy probably got fired. I'm in St. Croix.

  8. #8
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    Quote Originally Posted by man from trane View Post
    You can't use your gauges because you're not certified by whom? We have guys using gauges here one day and pouring concrete the next.
    In the States you need to take an EPA test before you do anything "reasonably expected to release refrigerant". That (very specifically) includes hooking up guages. Kind of dumb, I know, but I don't really a) want my butt on the line with the EPA, 'cause I know they're watching us; and b) don't want to potentially release 250lbs of (expensive!!!!!) refrigerant without my butt covered.angel:

  9. #9
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    Quote Originally Posted by man from trane View Post
    You can't use your gauges because you're not certified by whom? We have guys using gauges here one day and pouring concrete the next. They're not certified to mow grass let alone do refrigeration work. But if that's the rules where you live, that's probably a good thing.
    EPA. July 1, 1994. Montreal Protocol. 196 Nations have signed, ODP, GWP.....doesn't ring a bell? You got it nice down there on the warm islands!

    Up here we have to recover refrigerant. Cant' just pull the stopper and let her fly when changing a compressor. Kinda sucks but it's all hourly wage.

    Didn't the ratification in 2009 include you guys too?

  10. #10
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    Anyone know the ratio of EPA officers to Unicorns?

    because Ive sure as hell never seen one....only mythical stories

  11. #11
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    You know I forgot about that. I am EPA certified but down here no one cares except United Ref when I buy gas. I do reclaim, mostly because I can resell the gas, but almost no one else does. I've seen guys blow the entire charge of a 5 ton AC in plain view of the public. I don't think we have EPA guys on island.

  12. #12
    Quote Originally Posted by Phase Loss View Post
    Anyone know the ratio of EPA officers to Unicorns?

    because Ive sure as hell never seen one....only mythical stories
    EPA confronted us on the side of a store. They were interested in why the water runoff was very foamy. Told to knock it off. I was not asked for my card.
    EPA looked into our dumpsters and found the tabs on most of the bottles not punched. We were told we better punch them.
    A guy was filming me at the roof weather pacs once which caught me by surprise, I got nervous. They asked me some basic questions and left. Do not know who they were.

  13. #13
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    Quote Originally Posted by man from trane View Post
    You know I forgot about that. I am EPA certified but down here no one cares except United Ref when I buy gas. I do reclaim, mostly because I can resell the gas, but almost no one else does. I've seen guys blow the entire charge of a 5 ton AC in plain view of the public. I don't think we have EPA guys on island.
    You RECLAIM????
    That is a fairly expensive set up to invest in to meet standards. Or do you recover??? If you recover, the refrigerant can only be used on the original cusomers equpment.
    If you really know how it works, you have an execellent chance of fixin' er up!

    Tomorrow is promised to no one...

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