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[grendil]

Gents I posed a ? about recovering R123. Several responses mentioned they ran the recovery machine over night. I would be concerned about freezing up. Even if the Barrels were Dry. Or am I just a worrier??:D

[nun]

Dont run it overnight.

[txhvac]

I've been in involved w/ that, as long as you have your pumps (evap&condenser) running freeze up will not occur. The only time I've done this ,or seen this done, was during vapor recovery, all the liquid had been removed. It's always good to be concerned about what's going on, I think you should be worried if you didn't ask anyone. Hope this helps.

[jayguy]

I've been in involved w/ that, as long as you have your pumps (evap&condenser) running freeze up will not occur. The only time I've done this ,or seen this done, was during vapor recovery, all the liquid had been removed. It's always good to be concerned about what's going on, I think you should be worried if you didn't ask anyone. Hope this helps.

yep. run your pumps to get out the liquid, then finish up recovering vapor overnight. never froze up an evaporator before. if you can run your pumps overnight without overheating the loop, it wouldn't hurt.

[Carrene #2]

I'm with Nun.
Never run your equipment unattended.
Yes, the possibility for freeze-up exists, especially if you are unable to run pumps. Which is generally the case around here.
I usually try to finish my day with recovering vapour down to 18" hg vac. ( r-11) and let system stand overnight and then finish recovering vapour the next morning. Any time you might actually save by doing it all in one go, can be lost by having only one freeze-up in 10 years.
I work for a company that pushes for the bottom line on jobs, but would rather not have any problems and call backs, so it's do it right the first time.
A quote from, where I'm not sure, comes to mind, " why is it that we can't find the time to the job right the first time, but can always find time to do it over again" or something like that. I'm gettin' older and forget how it actually went, but I've never forgoten what it meant.

[jimbob73]

Have to stir the pot here! Don't need no stinking flow for R123 recovery.

[mallron]

I'm with the guy with two first names (JimBob), you guys would piss me off trying to recover gas from a chiller like that. Just drain the barrels. You're gonna push-pull all the liquid out anyway. Have a sightglass in-line with your hoses going to your recovery cylinder. When no more liquid shows in the glass switch to vapor recovery, set the relief on the cylinder and go home.


-JB

[acjourneyman]

I wouldn't run the pumps either, or drain the barrels and I always run the reclaim overnight on vapour mode.You should know if you have all of the liquid out of the evaporator and if it is trapped in the economizer or anywhere elso for that matter, it won't freeze up the tubes.

[jimbob73]

I wouldn't run the pumps either, or drain the barrels and I always run the reclaim overnight on vapour mode.You should know if you have all of the liquid out of the evaporator and if it is trapped in the economizer or anywhere elso for that matter, it won't freeze up the tubes.



Exactly!

[controldude]

Typically we use a portable purge on our recovery Tanks also.

[Healey Nut]

R123 Recovery. 9yr Trane tech lots of 123 experience .Recover the liquid first using push-pull method into storage tanks. Switch to vapor for overnight no pumps no circulation needed . how can you freeze the tube if theres no liquid to boil off ???????? We use the Trane Evacupac and 650lb Storage tanks. liquid recovery should be about 2/3 hrs for 1000lbs assuming chiller is tight and bundles are at room temp . babysitting the process is only needed if theres air in chiller or lack of storage tanks to allow for possible non- condensables Fill one tank at a time dont daisy chain them together,less chance of leaks on quick connect fittings.Save last tank for vapour process .The colder the water for the condensor on your recovery unit the better .dont put the water through the condensor at full flow it decreases the heat transfer rate .

[chiller mekanik]

Re - tubing a chiller or even part of the tubes is very costly & could be embarrasing if you are the one responsible for it.

Not trying to stir the pot but I would like to spell out some facts as I know them.

I think we all agree that we can remove the liquid through push/pull or with a liquid pump or both.
In my opinion, push pull works fine with large hoses, the truth is, the liquid transfer shouldn't take long anyway.

You can speed up the vapor recovery with three methods:
1) modify your recovery unit for large hoses.
2) modify it to use more than one hose.
3) circulate chilled water through the condenser instead of munincipal water.

Now lets talk about when to transfer to vapor.
It has been stated that a sight glass will reveal if all of the liquid is gone.
I say this with all due respect, but I completely disagree.

I would urge everyone, especially if you have a machine with a sub cooler or a water cooled oil circuit to consider the following methods or procedures.

When you "think" you are done with the liquid, go ahead & switch to vapor recovery.

Make sure your chilled water pump is on. (cheap insurance)

Check your temp/pressure conversion chart, when the pressure of the refrigerant you are recovering equals 35*, STOP! Valve off the recovery unit & check that pressure again in 30 minutes, if it rises, there is still some liquid trapped in the chiller somewhere.

Start recovering again, when you reach 35*, stop, valva off & wait another 30 minutes.
When the pressure no longer rises, then & only then is it safe to proceed past the point of freezing.

You should still have your pump on.

And under no circomstances should you leave it unattended over night.

While your at lunch or going to get parts & as long as you are close by, its okay to let it run unattended, but only after you have gone below freezing.

The problems I have with leaving it unattended are many, but just to cover a few; What if someone comes in at night & turns the recovery equip off or what if they change your valves around or somthing like that?

What if the recovery equipment fails?

In my mind, leaving it unattended is never a good idea.

Its up to you to make it idiot proof.

I'm sure some will think this is overkill, but I would rather error on the side of caution.

[mallron]

Now lets talk about when to transfer to vapor.
It has been stated that a sight glass will reveal if all of the liquid is gone.
I say this with all due respect, but I completely disagree.


You can disagree if you like, disrespectfully even, but I think you're going way overboard. The sightglass WILL show you if there is no liquid in the evap. You can then do a separate liquid recovery on the economizer if you wish, but there are no tubes in the economizer so who cares if there is some liquid trapped there.

Secondly, if some butt-head bothers your recovery set-up while you're away then they just bought the job. Period.

I guess we're gonna have to agree to disagree.

-JB

[acjourneyman]

I agree with Mallron, you are being way to anal in recovering and I hope your customer isn't paying you to babysit vapour recovery. For one, if you have liquid sitting in a volute or anywhere else it is going to take time to boil it off, time that I don't have to wait while I watch a recovery unit do what it is designed to do, recover refrigerant.

[txhvac]

From the posts I've read, it seems to me that everybody has a different OPINION on how it can be done. Whether or not you run the vapor recovery overnight, if you run the pumps during recovery, site glasses, sit w/ the machine, WTFE! Nobody is necessarily wrong. Just pay attention to what you're doing, & if you don't trust running the recovery overnight, DON'T DO IT!!!!

[Healey Nut]

Ounce the liquid is out of the evap bundle which is where it is when the chiller is off.you can switch to vapor recovery ,yes there may still be liquid in other parts of the chiller{economizer/cross-over line on double ender]but as we all know there are no tubes there so who cares. the recovery rate of the evacupac is not fast enough to create a fast enough pressure and temperature drop to freeze a tube.you would have to have a monster vacuum pump to drop the pressure fast enough.As far as running overnight the evacupac has double high pressure controls and the tanks have a high level cut off. these can easily be checked and should be checked at the start of the recovery process.these controls should if working properly protect the process should any moron *&%# with the unit .????. as for using chilled water for the condensor ,yes it is better but if you dont have another chiller running your screwed also if your garden hose bursts at 2am thats alot of water and chemical down the drain , city water is cheap and cold enough.

[grendil]

good recovery talk, Myself I would rather pay some one a extra $850 and baby Sit rather than risk owning a Retube and lost Confidence. Thanks boys!!