Unit has a leak? What more to try.....?

[alexio]

I bought this unit say 3 months ago. Didn't really have time to do extensive testing so I just fired it up one time. Saw sub-40C dual-headed, nice. Stupid me didn't look at pressures then, so I can't compare now. After that I was in the hospital for 5 weeks and when I came back home I smelled something. I had no idea what it was and nobody else in the house smelled anything. I smelled gas...

A few days later I had some time to play with the unit, so I fire t up. Weird thing was, I couldn't get it below -32C. Pressure were something like 1 bar low-side and 12 bar high-side. So I PM'd Piotres for some tips and he said I should turn both CPEVs counter clockwise until high-side was 12-17 bar and the low-side was at 0.2-0.5 bar (yes, the unit has a rotary).

Today, about 2 weeks after Piotres' tips I tried to tune the unit once more. I checked the high-side static pressure and it was 5-5.5 bar. I knew it was kind of low so I became a little worried and I fired it up.

High-side is rather stable at 9-10bar (should be 12-17bar) and low-side is very dependent on CPEVs setting. I tried everything from 0 bar (meter reads even negative values) all the way up to 1.5 bar. I can't get the evaps below 2 degrees Celsius. I'm testing without a load.

Anything else I could try, or does this unit need to be fixed? Gas in the unit is 80% R410a and 20% R507, or close to that.

Thanks for you help,

Alex

[LukeXE]

Leak my friend, if pressures are that low (I mean highside) and now you can`t get lower than 2*C...there is too small amount of gas, so unit is leaking.

[alexio]

Leak my friend, if pressures are that low (I mean highside) and now you can`t get lower than 2*C...there is too small amount of gas, so unit is leaking.
Bummer, But I didn't really expect otherwise. I guess I'll let it get fixed then :)

Do you happen to know if R410a and R507 are toxic or unhealthy?

[LukeXE]

Bummer, But I didn't really expect otherwise. I guess I'll let it get fixed then :)

Do you happen to know if R410a and R507 are toxic or unhealthy?

Hehe, they are safe in small amount, in your unit you had about 200g of gas, this is much to small to be unhealthy IF R410 or 507 is unhealthy, but I don`t think so.

[Brettbeck]

I think R507 is a HFC, not sure about R410 though...

[LukeXE]

lol, if he hasn`t died already, he will live :D :D (joke).

don`t worry Alexio !

You will send that unit back to piotres or someone else will repair it ?

[jinu117]

Sounds like low side leak if it took so long to develop over time unless sudden rupture (which doesn't sound like the case). Usually, suction line, evap and metering device in this cases are suspect (as well as schraeder).

[alexio]

lol, if he hasn`t died already, he will live :D :D (joke).

don`t worry Alexio !

You will send that unit back to piotres or someone else will repair it ?
I'll work something out with Piotres. It's probably better to get it fixed in The Netherlands, because shipping is so expensive. You think 50/50 cost share is fair? He made a very good deal for me already and I have one year warranty, so I pay at least a part of the repair cost.

Sounds like low side leak if it took so long to develop over time unless sudden rupture (which doesn't sound like the case). Usually, suction line, evap and metering device in this cases are suspect (as well as schraeder).
One of the CPEVs is faulty it seems. It could be my imagination, but it felt like one of the CPEV's farted on my hand while I was turning it :D

[wdrzal]

ALL Refrigerants are toxic,Some are much more toxic than others.......What refrigerant & To what degree is the Question ! , amount of exposure and for what length of time must be considered as to determine total effect. Sometimes PPM (parts per million) can have effects. Each refrigerant is different . All can asphyxiate in large amounts.

Look up the MSDS (material safety data sheet) for each refrigerant, and Basic toxicity will be there ,effects and symptoms and exposure times and amounts.....if the "COMPLETE MSDS" is listed ........on the net, I seen where this is not always true & some info is left out........ Also "Poison control centers" will have proper information on hand as will a hospital emergency room.


As always, if you have any concerns contact A poision control center ,emergency services, or a Doctor.

[alexio]

As always, if you have any concerns contact A poision control center ,emergency services, or a Doctor.
Thanks. I know about these safety cards for substances. I didn't expect they were on the internet for freons. I'll just open a window, that's good enough for me ;)

OT: I really like to point out that Piotres did an amazing job building this unit. It's more than likely that it isn't a faulty braze, but rather a faulty component; probably one of the CPEVs.

Thanks for the info y'all :)

[wdrzal]

OT: I really like to point out that Piotres did an amazing job building this unit. It's more than likely that it isn't a faulty braze, but rather a faulty component; probably one of the CPEVs

I Agree , a properly made Braze Does not leak or fail............. Only a joint that received severe damage or more likely was made with the wrong rod or just a poorly made joint ........

Tip: I always check joints I can't see completely around with a small extendable mirror, To be sure the braze flowed completely around the joint in its "Liquidus" state and there are no pin holes. Much easier to reheat now, than charge a system & have to pump it down to fix a pin hole;)

[Revage]

I had a problem with piotres built unit too.
My friend who fixed it told me that it was brazed bad

[piotres]

I had a problem with piotres built unit too.
My friend who fixed it told me that it was brazed bad

It's not bad braze ..I think the problem is in flex hoses which we are all using in Poland ...that's why all my future builds will be having braided suction flex hoses :fact: (that which I've been using till now is without mesh, it like to crack just near braze, and just isn't good for static pressures over 10 bara) . Sorry guys.

I'll write more soon.

Regards
Peter

[boshuter]

Gas in the unit is 80% R410a and 20% R507, or close to that.

This is why I don't think it's a good idea to sell units with a mixture. If you get a leak in a braze joint and just have to heat it to fix the leak.... how are you going to top it off and maintain the same mix? Especially if all you have is "or close to that" ;) Problems can and will crop up with leaks now and then, most can be attributed to rough handling during shipping. If you use a commonly available gas there is no problem getting it topped off or recharged locally. I know people like to have their "secret" mix that gives a few degrees colder temps, and that's fine for your own unit.... but selling one to someone with a mix IMO is not a good idea. I try to stick with r507 or r404a, different gasses could possible give a slightly better temps, but if a problem crops up the owner will not have a problem finding someone locally that can recharge the unit.

[Revage]

It's not bad braze ..I think the problem is in flex hoses which we are all using in Poland ...that's why all my future builds will be having braided suction flex hoses :fact: (that which I've been using till now is without mesh, it like to crack just near braze, and just isn't good for static pressures over 10 bara) . Sorry guys.

I'll write more soon.

Regards
Peter
i had leak near compressor:(

[wdrzal]

piotres butting the ss braid over the inner ss corrugated tube just keeps from growing longer as far as I can tell and will do very little to stop a crack at the end unless there is a build up filler and getting the filler to completely flow thru the mesh will be tough, thats not its reason for the mesh.The mesh id changes as it is compressed or elongated.its generally stretched over rubber hose and a mechanical crimp is used to stop inner hose elongation and expansion.

any joint made has to 1: be constructed correctly mechanically first before brazing(correct thickness metal ,connection type & overlap,metal fatigue must be considered at stress points 2: must use correct filler(rod) and flux if stainless to cooper, 3: correct method & temperature of heating and applying filler.
4: leak test, 150 psi low side, 300 psi high side,is recommended but if you can't separate since these are small systems ,do as I do many times test all at once at 200 psi 5: check all brazed joint first visually,w small mirror if needed 1" to 2" round or equivalent will do. for filler flow and pin holes, then with a leak test solution,I like the ready mixed ones as they are thick and do not drip off w/applicator(bubble test)best test & be sure to test all brazed joints & components where this is a seal, around nuts,caps,flare nuts,compressor electrical pins and compressor inlet and outlet,valve core ,etc ,etc ,that may have a o ring or some other seal. inlets ,outlet thru can wall rarely leak unless damaged or overheated,same goes for around electrical pins,rarely leaks unless damaged. but check,especially on cheap compressors,but any compressor can have a defect that was not caught,all quality testing is not the same worldwide.Also check condenser U joints since they are so accessible in most units

After pressure test vacuum and retest with micron meter, this can be tricky as a small amount of moisture or refrigerant trapped in the oil will cause meter to rise, how fast is the preliminary key but moisture can also cause meter to rise on a leak free system.ultimately you should get the micron reading to stabilize.always below 1000 (RSES maximum recommendation).but I like 300 to 500 microns . you need a good manifold that does not leak and hoses that don't permeate.

ps: during visual inspection look for pinholes filled with flux or carbon,sometimes they wont leak until many cycles are run or even much longer. If you see a black dot ,on a otherwise good looking joint scrap at dot as it usually flux and carbon from the fuel that gets like a hard black glass or scale, and usually it floated to the surface and comes off.

If it can not be removed it may be a pinhole full of carbon and flux. The longer a joint take to heat the more carbon and flux scale you will have on the outside if purged with nitrogen or co2 on the inside, over heating also worsens this condition. take a pointed pick and try to determine if it is a hole.

pressure built up from purge gas can also cause pinholes

[t800]

ALL Refrigerants are toxic,Some are much more toxic than others.......What refrigerant & To what degree is the Question ! , amount of exposure and for what length of time must be considered as to determine total effect

With that principle you could say that all gasses expect air, are toxic? Personally i think R xxx refrigerants are "quite safe" compared to other refrigerants


This is why I don't think it's a good idea to sell units with a mixture. If you get a leak in a braze joint and just have to heat it to fix the leak.... how are you going to top it off and maintain the same mix?

Sounds like ss builders should consider more "unit will leak at somepoint" than making unit "not leaking" .:hehe: Make it good at one time and don't need to worry reparing it.

[SexyMF]

Swagelok make a great product for leak testing. 'Snoop'
http://www.sisweb.com/referenc/articles/snoop.pdf

In my case I found the safety cutout pressure switch to be leaking slightly.

[boshuter]

Sounds like ss builders should consider more "unit will leak at somepoint" than making unit "not leaking" .:hehe: Make it good at one time and don't need to worry reparing it.

It must be nice to be perfect :clap: ... not everyone is; that's why you see one of these threads now and then.... things can happen, shipping damage, seals leaking, accidents at home, etc.

[wdrzal]

Swagelok make a great product for leak testing. 'Snoop'
http://www.sisweb.com/referenc/articles/snoop.pdf

In my case I found the safety cutout pressure switch to be leaking slightly.

Yes read the MSDS for snoop 95% water 5% surfactant.

If you don't know what the last word means look it up telling you is too easy.I,m getting ready to wash my hands of this.;)

[piotres]

Hi

wdrzal thanks for lesson :) , but I reallt know about that ...all my suction lines together with evaps are tested under water and I use 30 bara as a test ;) . All braze points and flares I test with REFCO spray . As you have seen the leak appeared after sometime after building ...and for sure after some bringing unit from place to place and long transport from Poland to Holand :( . But I know ...that isn't nice :slapass: ...and as I have said I suspect suction line the most .

Regards
Peter

[wdrzal]

Piotres yes I know you do good work. Using the best materials you are aware of and techniques you know. But being a DIY site ever buyer must realize that most people selling these units do not have formal engineering experience.And almost all units are NOT designed by a professional engineer to for see many problems. I have seen noobs go from first build ever to a very prevalent builder and seller in a year or two. There is much not even mentioned or talked about on these sites that everyone needs to know.Not to mention the business end.

Everyone has to realize this is mainly a DIY site and many build for personal use, then thru requests they expand to sell some units, then some more, then all a sudden they are suppling many units before they really thought thru all the possible pitfalls.I don't believe for 1 second that people like piotres and others who do their best and honor any warranty if any was given or come to a fair conclusion would intend to sell a unit if they thought at the time it might fail in the near future.

We have a honest family here at XS and every one sets out with good intentions. but problem rise up.

In my opinion this happens for several reasons, many people sell units without realizing all the unseen costs in a business ,since this may be there introduction into one.cost of returned units,shipping damage,all the potential problems that can occur for starters. Then take most here who are self educated in this Field and still relatively near the beginning of their learning curve.While a single stage looks simple by there only being several parts, To understand refrigeration takes many many years. Designs improve as peoples learning curves do.

Nobody is born a pro, knowledge is a life long learning curve, So even with formal engineering education,I,m only half way thru my learning curve.
just doing this alone is a professional engineering feat to push single stage to wear it is as far as low temperature. And this is done mostly by DIY people here.

So before you criticize, think if you can do better first.

Say I Wdrzal wanted to build and sell a unit such as ocz did/does but on a personal DIY business as chilly and most do here(hope ocz does not mind this comparison,if so let me know and I will edit.) I would first consider if a reliable unit could be built for the selling price where I could make a profit.you need to source all materials and come up with a cost estimate,if I still decided to go ahead,I would have to Engineer and build a few prototype designs for performance and endurance testing, I would need to offer some warranty and need to know failure rates and how far I could push stock compressors for low temperature cooling.plus add the cost of expected RMA units to add to final price , Even that I did not manufacture the compressor,I am responseable to take care of warranty issues.And I would want to maintain a outstanding service as OCZ is noted for. Now even that I skipped dozens of considerations to this point I decide to go ahead and make a dozen a week. A DIY person has to order and source all the parts and deal with delays, shipping & part quality even before I build.Then go on to build, test, pack ,ship, and also deal with impatient buyers all by myself. So in a few month things look great making a little money and having fun doing it.

Then wham ................the metering device,compressor ,controller or any number of problems begin to arise, previous happy customers all a sudden have problems that can only be solved by returning the unit.The test did not predict this, whats happening? un-calculated cost start to occur no matter if the part suppliers give you replacement parts for free, your time to trouble shoot and repair can be longer that to assemble a new one,shipping costs for returns skyrocket,future orders fall behind because I ,m honoring and repairing what I already sold. Did not even touch the official tax and regulatory issues yet plus initial equipment cost to produce units at this rate ,even thats its only 1 per day.

So much to do, so little time,I was making a nice small profit but now all the problems are putting me in the red. and to boot I,m working 18 hours a day.

I got hundreds of units out there all using the same parts,how many more will develop problems,BOY I WISH I never started SELLING units.The work & stress is killing me,losing money and most important this is NO fun any more.

Any of this sound familiar to you builders or buyers

even production units from the major makers have a poor record to date.

This includes materials used, almost all units are pushing compressors way past their designed operating pressures to get the lowest temperatures, this risk must be accepted by the buyer as they should be aware most compressors are not made to function with a very low side pressure and all the related issues.

Me as a buyer I paid xxxx and expect a perfectly operating system, even that I am sort of aware of some issues,I still want extreme low temps pushing limits made by DIY builders, and I paid xxxx.

Builder frowns knowing what he charged doest come close to cover all the costs of materials RMA issues plus all other cost he forgot to add,just my light bill and phone bill quadrupled. Wonders where the profit went.

I wrote this for the sole reason to get buyers, builders and potential builders to really think things thru before they get in over their head & out of your control.

Ps: I wrote this rambling soap box speech without sleep for over 2 days if I don't get some rest tonight look out for un intelligible rambling tomorrow.

Walt