Correct Resolution? Copeland Scroll Compressor / Rust Inhibitor / TEV/TXV Sticking

margsuarez

I saw the issue come up a couple times on this board and other HVAC boards. I know most of the pros here do heating but are also versed in A/C.

I am looking for updates for the situation of TXV sticking due to manufacturing defect (POE rust inhibitor) in Copeland scroll compressors. It is affecting my Rheem unit (and the TXV in my ADP coil). What do you think of adding AC-Renew to address the issue of sludge forming and clogging the TXV? What is the proper method to flush contaminants from my system if my installer is willing to replace the TXV and compressor? Supposedly the manufacturing process has been reverted and no longer uses the bad rust inhibitor.

Here's a post I put on a different board - not sure if you all hang out there too. Wanted to tap your expertise.

http://hvac-talk.com/vbb/showthread.php?1909671-Correct-Resolution-Copeland-Scroll-Compressor-Rust-Inhibitor-TEV-TXV-Sticking

Thanks as always for your time.

marg

njtommy

Depending on TXV you have in the system I would just replace the txv, liquid line drier, flush the lin set and then possibly add AC renew. If you have a txv with a screen/ strainer in it I would absolutely replace it.

Paul S_3

What about flushing with rx-11?....replacing txv... replacing all driers....preferably a flare drier so it can be replaced easier in future.....and add ac renew....What is actually going on with system?

aircooled81

I dont know much about the flush kits, but i know they are not cheap.

If you want to save a buck on a compressor that isnt bad (the mechanic wont appreciate this post though)
Pull the compressor, tip it over at pour out the oil. Replace the oil. Replace the liquid line drier, use a clean up liquid line drier (like an hh or acid/wax catch-all), oversized.
Run the ac for 24 hours (not non-stop, just clock it for 2 to 4 days) then swap the drier again, or install ports on entering and leaving side and swap when it gets about 2 to 3 psig drop.
Replace the txv, the time spent trying to clean it is better spent with a swap out.
Just replace the liquid line drier till the pressure drop goes away. Might take a few visits, but its how i treat an acid burn-out.
Suction driers only used on severe burn-outs, but i always recomend they are removed after the clean up, if you choose to use one to protect the new oil.

John Mills_5

As I said on HVAC-Talk, Rheem will pay the dealer to go install AC Renew. 90% of the time that solves the issue. If it doesn't, change the valve. Keep RX11 out of it. Do what the manufacturer says to do.

njtommy

Just talked to one of the guys at work today. His own house he installed brand new York/ Coleman equipment he had problems. He replaced the txv and installed the AC renew or what ever they gave him to install. Ran the rest of the summer. This year his system started banging off on high head again. Not sure what he is going to do at this point.

margsuarez

Thanks for the responses.

Very interesting, @njtommy - this is where i was going with this query. I had two incidents last summer - both during heat waves. First was frozen evaporator coil. Second was hi pressure limit shutdowns. Both seemed to go away after relocating (first incident), then shocking (with icecube, 2nd incident) the TXV sensing bulb. But we had no more hot days after the second incident and I pressed the installer who offered the warranty replacement of compressor and TXV.

Obviously installer is talking to Rep / Manufacturer who agree to replace compressor, even though it doesn't seem necessary.

Hence my question about official updates from manufacturers. My gut feeling (and probably your friend's too) is that they don't know how to totally eliminate this gunk and this cooling season will probably be hectic for all you pros and aggravating to us HO's.

Anybody else have new info/insights?

BTW I have been bouncing ideas off @Paul S (thanks Paul!) who was involved in the original install and whom I plan to hire to maintain/tweak my boiler.

I may pick up the phone and call Home Depot who subcontracted the original install, if only to continue to document my concerns.

marg

njtommy

Even with a new compressor there is no guarantee you want have problems again.

aircooled81

Refrigerant travels through the liquid line at about 300fpm, through the suction line at about 750 to 1000fpm. Ask the ac guy if the supply house can give him wax/slidge removing driers. Instal them, and replace as they get fouled.
Think of these as filters, catching the garbage, then he comes over and throws the trash out.
Changing the compressor/oil will speed this up. Its likely 90% of the oil is in the compressor. I assume the oil is where the problem is.

John Mills_5

What's wrong with doing it the way every manufacturer tells you to do with the rust inhibitor issue?

margsuarez

the intent is to educate myself as much as possible before finding out at the next heat wave (or 70 degree day, as @njtommy 's story might suggest) that it's still not fixed.

I lose money in terms of lost work each time I have to take time off to provide access for repairs, not to mention the inconvenience of living without AC during a heat wave. my unit was installed in June 2014. two incidents too many for such a new unit. from a homeowner's standpoint, "it fixes the problem 9 times out of 10!" is not a satisfying answer. As an elevator mechanic by trade, I know that kind of reasoning does not satisfy the building management. But I also understand that troubleshooting is an incremental process. I just want to make sure we are following the most thorough process this time around to avoid callbacks.

look, if this wasn't a wide-spread, repeating, documented issue I wouldn't sweat it. but it is. manufacturers sent out memos 1.5 years ago and I am still reading reports of trouble even after manufacturer's recommendations were followed. then no more memos from manufacturers? what conclusion do you draw?

at any rate, as no one seems to have updated information (except how adding AC Renew and replacing TXV didn't work in their case), I don't really have a choice but to let the installer do their thing next week. we will see...

thanks for your input.

marg

margsuarez

Good morning,

Here is an update. Installer came out on Monday and replaced compressor, TXV, and filter drier under manufacturer's warranty. They did not inject AC-Renew, but I trust they were in contact with the manufacturer rep when this decision was made.

The techs removed the old compressor, txv, and drier, then separately flushed the lineset, evaporator coil, and condenser coil with Pro-Flush/Nitrogen; installed new components; filled with Nitrogen to test pressure; pulled a vacuum; then charged with Virgin 410A to manufacturer's spec (6.5lbs).

I looked up the serial # of the replacement compressor. It was manufactured in March 2013, which is before the change of manufacturing process according to Rheem bulletin (40th week of 2013 through the 37th week of 2014). Incidentally it is larger in volume (more POE oil) and more efficient than what it replaced (EER 17.45 vs 15).

Compressor was humming away when the techs left. Pressures at 65deg outside temp were correct. Brought the house from 75 to 72 in less than 2 hours.

Will update when we are able to test the unit under load (too cold out now).

marg

unclejohn

The re nuz worked fine for me

ChrisJ

How low of a vacuum did they pull and for how long?
Did they flow nitrogen while brazing?

Just curious.....

njtommy

I would say neither Chris. Most guys don't purge with nitrogen while brazing and most guys don't have micron gauges that are even worth using.

ChrisJ

njtommy said:

I would say neither Chris. Most guys don't purge with nitrogen while brazing and most guys don't have micron gauges that are even worth using.

If a guy didn't both pull out a nitrogen tank with his torch and have a good micron gauge with his pump I'd have to ask him to stop working. I'm not sure I could be polite about it, it's a bit disgusting but I'd try.

I honestly tried vacuuming with nothing more than a manifold gauge, I tried. I couldn't, I had no idea where I was. Am I low enough? is there a leak? Should I stop? What's going on?

I then bought a Yellow Jacket Micron gauge.

njtommy

Yellow jacket makes some really nice stuff. I have there micron gauge as well. I've seen it time and time agian guys just let the Vacuum pump run for an hour or so and then start charging the unit. Old school refrigeration guys would even pull a vacuum they would just start dumping gas in a system and let it purge out the other side for a few seconds then just close the valve and keep adding gas.

ChrisJ

njtommy said:

Yellow jacket makes some really nice stuff. I have there micron gauge as well. I've seen it time and time agian guys just let the Vacuum pump run for an hour or so and then start charging the unit. Old school refrigeration guys would even pull a vacuum they would just start dumping gas in a system and let it purge out the other side for a few seconds then just close the valve and keep adding gas.

I'm not sure if it's necessary, but I was taught to pull a long vacuum and heat the evaporator and condenser if possible. Then fill with nitrogen and pull a deep vacuum again. I did a 450 micron vacuum but some guys seem to like to go lower, 200 microns or so.

Paul S_3

Sometimes it is difficult to achieve low microns....because refrigerant is still in the refrigerant oil....then i heat the crankcase with my heat gun that usually solves the problem....on new installations i usually can pull a vacuum well below 500 microns around 250 to 300....i also heard if you go below 250 microns there can be problems with the refrigerant oil...i always braze with a nitro purge , remove shraders and use the appion vacuum rated core removers with my UEI micron gauge ....im going to upgrade to the Bluevac soon.....i do not know 1 other contractor that use a micron gauge and use a nitro purge....besides the few supermarket techs i know that are required to use it

ChrisJ

Paul S said:

Sometimes it is difficult to achieve low microns....because refrigerant is still in the refrigerant oil....then i heat the crankcase with my heat gun that usually solves the problem....on new installations i usually can pull a vacuum well below 500 microns around 250 to 300....i also heard if you go below 250 microns there can be problems with the refrigerant oil...i always braze with a nitro purge , remove shraders and use the appion vacuum rated core removers with my UEI micron gauge ....im going to upgrade to the Bluevac soon.....i do not know 1 other contractor that use a micron gauge and use a nitro purge....besides the few supermarket techs i know that are required to use it

Well,
Now you know a DIYer that uses both.

Hi!

njtommy

Triple evacuation is a common practice for larger systems and any time your try to clean up acid in the system.

Some manufacturers want you to pull down to 200 microns and they also want it to hold there for 10-20 mins with outgoing up with out the vacuum pump running.

Some of the system I've worked I leave the pump run for 24hours or more. I leave the job site to do other work. Then come back a few hours later break system with nitrogen change vacuum pump oil. Do that a couple times that day and just leave it run over night. Hope for the best in the morning.

Paul S_3

@njtommy just for my knowledge what is your acid test procedure? I just recently purchased a couple of these from the supply house .....do you recommend using these or another brand? I know acid is formed mostly from poor evacuation, moisture and non-condensables any orher causes?

njtommy

That style of Acid test kits are great. I use them as much as possible. They also have ones where you don't need the oil test. You push them against the service valve and it uses the refrigerant for testing. Great for scroll and hermitic compressors.

Acid will also form from over heating the compressor and compressor oil. Could be from too much super heat or even system problems like dirty coils and running high head pressures. If you oil starts to look like Coffee it's a sign of over heating or being burnt. I'm sure it also caused by poor installation. Leaving dirt or copper Shards in the system. Could also start to see copper plating take place on semi hermetic compressors.

This is a valve plate from an Carlyle O6D compressor I replaced last summer.

njtommy

Also you can add acid away or acid scavenger to the system it works really well. To help clean it up.

njtommy

autopsy of a compressor Is a great book as well.

Paul S_3

Thanks @njtommy do you have the name of the product that does not need the refrigerant oil to test

njtommy

I get this at United refrigeration

@Paul S

Paul S_3

Thank you

margsuarez

hi @ChrisJ -

I am pretty sure they did not flow nitrogen while brazing. i know they used nitrogen with Pro-Flush to purge 1) each line in the lineset; 2) the evaporator coil; and 3) the condenser coil. Then after brazing they filled with nitrogen to hold pressure (15-20 min?) then pulled a vacuum (also 15-20 min?). not sure what a micron guage looks like but it was the same gauge he used next to check pressures during filling (which was done by weight).

I still have a complimentary preventative maintenance left until August with this company so I plan to schedule a visit during a hot day so they can verify the pressures/operation.

still haven't had to turn on the unit. I will update when I've had a chance to verify/test.

Thanks
marg

ChrisJ

margsuarez said:

hi @ChrisJ -

I am pretty sure they did not flow nitrogen while brazing. i know they used nitrogen with Pro-Flush to purge 1) each line in the lineset; 2) the evaporator coil; and 3) the condenser coil. Then after brazing they filled with nitrogen to hold pressure (15-20 min?) then pulled a vacuum (also 15-20 min?). not sure what a micron guage looks like but it was the same gauge he used next to check pressures during filling (which was done by weight).

I still have a complimentary preventative maintenance left until August with this company so I plan to schedule a visit during a hot day so they can verify the pressures/operation.

still haven't had to turn on the unit. I will update when I've had a chance to verify/test.

Thanks
marg

I'm betting if the manufacturer knew this they would not be happy.

Nitrogen must be flowed while brazing to prevent black junk from forming inside the tubing which will then contaminate and clog who knows what. This may take weeks, months or years but I highly doubt any manufacturer accepts brazing without flowing nitrogen. @Techman what do you think? Immediate void of warranty?


A micron gauge is a vacuum gauge that shows how low of a vacuum they pulled. Perhaps their manifold set is digital and has one built in? I don't know.

Here's a picture showing my Yellowjacket micron gauge. It's the blue and yellow meter with the black coiled cord. They get connected as close to the unit being vacuumed as possible. The blue and white analog gauge is the typical crummy manifold set gauge, it's practically useless for vacuuming but I use it for pressure testing with nitrogen on these units.

ChrisJ

Here's a video showing the difference between brazing with, and without nitrogen.

https://youtu.be/CKIP7k_FPRs

margsuarez

i should clarify - it is possible that i did not see the digital micron gauge, or whether the tech was flowing nitrogen through a service port while brazing (as required by the manufacturer). i did see the installation of "nipples" on the lineset ends, as shown in the video at timestamp 3:33 or so. these were used to purge. so i suppose it is possible that nitrogen was hooked up to a service port on the air handler when lineset was being brazed back together? but it didn't grab my attention (would it have made a hissing sound before the fitting was finished being brazed?)

all I know is the tech assured me that everything was being done "by the book"...

marg

aircooled81

Marg, I'm sure your ac will work great.

We apply the purge when we braze all joints, it prevents the oxidation of buring inside the pipe and fittings. Filter drier can catch some of this if it's floating around.
We can use the mircon guage to determine how many small particles of moisture may be creeping around, or if i tiny tiny leaks exists. This is while we pull the refrigerent system in a vacuum.
I typically try to achieve 500 microns on a system that holds more than 15lbs refrig, and 250 on anything smaller. One equip manufacture we instal requires 250 microns for 24 hours before start-up can commence.
these guys are right about the correct practice for brazing and evacuating a system. The life span of the equipment is 10 fold when appropriate measures are tanken to keep the inside clean and dry.
But I wouldn't loose any sleep over it.

Paul S_3

micron gauge and nitrogen purge rig.....the only thing with the nitrogen purge setup is that when i set it to the uniweld settings for nitro purge 3 to 5 CFH it seems very low pressure....like non-existent..... @aircooled81 what do you use for nitro purge? sometimes i dont know if its working i myself have never cut open my piping....before i braze, i fit the whole job.(residential) i do a complete nitrogen sweep at high pressure and the i "Chase" the nitrogen fitting by fitting....i nitro purged all my installs....im going to admit if i have to repair a leak real quick on a crappy system ....ill just pump down , braze (w/o nitro) evacuate always with micron gauge...and recharge....i purge 99% of the time.... rig

aircooled81

Paul S,
I like your set-up, looks clean.
I'll try and remeber to post some pics and models of my nitro purges and micron guages.
I, like you, will fit the whole loop then start the purge. Sometimes I get weirdo 90 that needs to be brazed on the end of a lineset sticking out the side of a wall then shoved in, 1 joint here and there doesn't seem to kill me with no purge (ohh boy)
My most common reg for nitrogen purge has 3 settings, no pressure regulation. It has braze, purge and test. I usually set the highside for the purge (either liquid line or disch if doing condenser coil repair) then purge to the low side. I try to go the same direction as the Liq Line drier flow. I use the braze setting which is minimal cfh, if I have a lot of joints or schrader taps in the loop I find the purge setting (likely double the cfh) is addequate.
I feel the low-side by licking the back of my hand, or putting a refer hose on the fitting at the end of the loop and bringing the hose up to my lip, then I can feel if I have flow. Over the years I stopped worrying about flow volume too much. IMO if there is even a tiny bit of flow, its nitrogen, if there's too much flow I wont get good penetration with the silphos.
When I have flow through the whole loop, I can then hit high and low side fittings as I go, so I dont have to follow the piping and come back past fittings skipped trying to follow the purge.
Somehow I think I can notice if there is no nitro purge while brazing, the joint doesn't seem to heat the same and the silphos doesn't flow as easy?
Regarding Micron guages, I have 2. I got the yellow jacket in the blue plastic box, and a CPS. The CPS is the one I seem to use the most, though it is not as sensative as the yellow jacket. I pull the schraders on systems larger than 10 ton to evacuate faster. I use a 10cfm vacuum pump, so I'm pretty fortunate to have that fat boy. I'll ususally attach my micron guage to a valve on short hose so I can valve it off whenever I break pressure with nitrogen, or charge.
I find that unless it was a fresh new system, small, or not open for long at all (quick repair) I can achieve 500 microns the first shot. When the system has been open for over 30 minutes, ran flat, or has new piping, I usually need to break the vacuum to 0psig with nitrogen multiple times, and change my vac pump oil. I usually pull the initial vacuum with the existing oil in the pump, then change the oil after I get down to 27"hg or around 2000-5000 microns, if it's not pulling down fast enough for me.
I let the system hold at a specific micron value, like 1000 for instance, for 30 minutes. If I have a rapid climb, there is a small leak. If I have a slow climb (lets say 1000 to 1300 microns) in 30 minutes I figure I'm boiling refer in the oil or still have moisture. If I cant pull to 1000 microns, large leak or a hell-of-a-lota moisture.
Most cases, after pressure test, but before evacuation, I blast the high side with nitrogen out the low side for 5 to 10 minutes. I think this is similar to what you mentioned. My idea here is to help force any water molecules one direction. I do this similar when I brake the vacuum, send it in the high side, then when I get to zero, only pull vacuum on low side the first 10 minutes. I'm trying to pull moisture one direction basically. After a short period I open the high side valve on my manifold to continue evactuation.
Big systems (over 15lbs refer) I like to see 500 microns hold for an hour (maybe climb to 540 or 550), small systems I like to see at 250 (maybe climb to 280 or 300) microns for an hour. I find tasks to keep my self busy while I monitor the guage, patience is hard to come by and staring at it every 5 minutes is tempting if you're not busy.
I keep spare o-rings for my hoses, I have found the leak on my evacuation drive me nuts because it was my hoses. I have found hoses leak that bubbles didnt show, but after replacement of those macaronni hose o-rings fixed it. When they start to get stiff, I swap them out.

ChrisJ

My nitrogen setup isn't anything special.

Since the stuff I work on only has 1 valve I connect my tank up and increase pressure until I can hear it hissing out of the joints some, not much. I wait a while, and then start brazing. Before making the last joint I shut the nitrogen off and let the pressure die off, then I make my last joint.

I do want to buy a flow gauge, but I suppose it's not really needed for my work.




Here's a closeup of some of my bazing, it's the best I have on hand. I'm not perfect, but I think my work is decent. I do wish I kept the heat away from the evaporator a little better though.

JUGHNE

A doubled up wet rag hanging over the evap coil may have prevented that. (cotton is good).

Another product is Thermo-Trap by Nu-Calgon it is a heat absorbing gel in a spray bottle (very clinging...rinses off with water.) I spray it on AC svc valves or filter driers. Still wrap with wet rags. Saves paint on LLFD and O rings in valves. Also use it for soft soldering ball valves etc. Just don't apply to any surface you want to heat.

Spray it on wood floor joists to avoid the branding during sweating water lines. That char never leaves a very professional look, especially in new work.

margsuarez

OP here with the update I promised.

After several days with the temps in the 80's and 90's I am glad to say the AC is working great. With ceiling fans the house is comfortable even with the stat set to 80. I even tried a setback yesterday and let the indoor temp rise to 85 -- the unit is able to recover within a few hours.

As the unit was charged back in April with outdoor temps in the 60's I was planning to have the installer come back to verify the charge in hotter weather.

This morning I was standing next to the air handler and could hear a sizzling/hissing noise coming from one of the lines (liquid?) in the vicinity of the filter drier.

Is this something to be concerned about? Does it indicate a problem? I have made an appointment with the installer for a week from tomorrow, when temps are forecasted to be between 75 and 91. Besides verifying the charge and checking into the noise is there anything I should make sure gets done during the visit?

Thank you for your collective expertise.

marg

JUGHNE

Did the filter drier feel the same temp as the liquid line? If cold it could be partially plugged.
The TXV can produce a hissing sound as it passes liquid that is turning into vapor inside the coil.

Paul S_3

sometimes....when a unit is undercharged i will hear that sizzling noise at the air handler/evap coil....it usually goes away when i charge it correctly.....maybe there isnt a full column of liquid going to the txv...subcooling is probably at 0F....a air conditioning system may seem to be working fine with an incorrect charge.....also what @JUGHNE said is correct. have the installer charge your system by subcooling....which is high side pressure converted to temperature minus the liquid line temp....usually 10F is ok....it should state it on the condensing unit.....also vertical rise can affect the amount of subcooling you need.

JUGHNE

I believe it has been brought up before; why don't we put a liquid line sight glass after the LLFD at the evap coil? would that make things simpler......I guess systems would get overcharged then.....assuming a clear glass would be good and add more to be sure. It seems to work in refrigeration but there we have a liquid receiver to compensate for extra charge. IMO