Vacuum and charging DD

[stockhatch]

Ok, I have a nearly complete system(minus fan) So I am pretty much ready for any advice regarding evac and charging. I want to do a triple evac, and I have propane to purge with.What is the best way to go about this without introducing air into the system when purging?

http://img.photobucket.com/albums/v46/stockhatch/side.jpg

http://img.photobucket.com/albums/v46/stockhatch/tools.jpg

Thanks :)

[Stewie007]

Technically you should use dry nitrogen on a triple vac. I don't know if propanes good or not good.

[cold_ice]

If he uses propan as refrigerant, there's no problem when he uses propane for purging.

[wdrzal]

the refrigerant you are going to use is fine. small amount of propane will be released durging purging and pump down so do in a well ventalated area. first hook your yellow hose of gauges to tank and purge manifold and lines of air.If your lines are quick seal I just use a schraeder valve to purge line with . walt

more to come:

[stockhatch]

So any suggestions on technique? I dont think I have the proper valves to connect everything right. I dont see how to purge without introducing air to the system.

[stockhatch]

Oops, you posted at the same time I did. Ok, Ill do that.

[wdrzal]

Since you did not have nitrogen to use during the make up,(solids may be present) I would only purge system with refrigerant vapor through the high side valve until it exits the low side valve(remove schrader valve) do this by connecting the red hose to high side port. purging in the other direction could risk blocking cap tube.When propane vapor exits the low side valve replace schrader valve. let system build with tank pressure,this is also your final leak check. more to come walt

[wdrzal]

now connect blue hose to low side port. you should now have both hoses connected to system and yellow hose still to tank, close valve on propane tank. be sure valves on manifold are closed after purging.both gauges should read between 100 and 125 psi depending on ambiant temp. Now you want to get ready to move yellow hose from propane tank to vacuum pump. before you hook to vacuum pump you MUST RELEASE the pressure to 2 to 5 psi this is done so the pressure does not damage the vacuum pump. you do this by slightly unscrewing the yellow hose under the manifold and opeaning the low side valve until pressure in system bleeds down. retighten connection under manifold and move yellow hose to vacuum pump

more to come; walt

[wdrzal]

Now you start the tripple evac process. it is recommened that the first 2 pump downs go to 1500 microns and 500 for the last pump down. But since you do not have a micron gauge ,just reley on the vacuum gauge of the low side manifold compound gauge,vaccum too you get the lowest acheivable reading. Your pump will pull a deep vacuum but with out a micron gauge you just won't be able to confirm this. with your pump I would estimate to let it run at least 10 to 20 min.

more to come; walt

[stockhatch]

Since you did not have nitrogen to use during the make up,(solids may be present) I would only purge system with refrigerant vapor through the high side valve until it exits the low side valve(remove schrader valve) do this by connecting the red hose to high side port. purging in the other direction could risk blocking cap tube.When propane vapor exits the low side valve replace schrader valve. let system build with tank pressure,this is also your final leak check. more to come walt


Ok did this, and now Im pulling a vacuum on both sides. Im supposed to pull from both sides right?

EDIT: BTW, no leaks evident searching with soapy water :banana:

[stockhatch]

Awesome. The pumps makes and intermittent loud gargle. Is that normal? It only does it every now and then. Sounds kinda like an outboard motors exhaust. I assume thats where its exhausting through the oil.

[stockhatch]

All my gauges are pegged out at max vacuum. The manifold low side is past 30in and the pump is past it 760mm reading.

[wdrzal]

once you start pump,open low side valve and evacuate to lowest hg reading. you do not want to open high side valve because you risk pulling somethig backwards through system and pluging cap tube. After lowest reading is reached close low side valve.shut off pump first evac is complete

more to come; walt

[stockhatch]

K. Well hopefully I dint pull anything into the cap tube....I have it situated like you said now :)

[wdrzal]

Awesome. The pumps makes and intermittent loud gargle. Is that normal? It only does it every now and then. Sounds kinda like an outboard motors exhaust. I assume thats where its exhausting through the oil.

your pump has a ballast valve just make sure this is closed,clockwise closes it. if it is opean you will not be able to acheive a deep vavuum. I will explain latter what this is for. walt

[stockhatch]

Sure thing. Thanks for the walkthrough BTW... :D

[Jimi...]

Can you provide some pictures with the Pump and everything connected up please Stockhatch? :)

[wdrzal]

now you need to break the vacuum with the refrigerant. remove yellow hose from pump and move to propane tank. open valve on tank,then purge air from yellow line by loosening fitting under manifold. Then open high side valve to let just enough vapor into system to 2 psi. close high side valve. move yellow line to vacuum pump and repeat outlined method until 3 pull downs is acheived now you are ready to charge. walt

[Jimi...]

wdrzal, would I follow that method if I was charging my unit with R22 Freon?

[stockhatch]

Sweet! Thanks again. How long can I wait before I charge since I dont have a fan for my condenser? Should I just charge till theres like 5PSI or so in there and wait till I get a fan to go any further? At least that way I could hook the hoses up later without pulling anything INTO the system.

[gkiing]

your pump has a ballast valve just make sure this is closed,clockwise closes it. if it is opean you will not be able to acheive a deep vavuum. I will explain latter what this is for. walt

This must be open during startup. Also with that particular vacuum pump start it and then connect your gauges, and change the oil after every time you use it if you want it to last.

[stockhatch]

Hmmm, you say the valve should be closed, but it doesnt pull any vacuum with it closed...Its labled "intake", so I would assume it needs to be open. There is another twist valve labled "gas ballast" is that the one you mean should be closed?

EDIT: the unit also has on it to only open the gas ballast for "cold weather startup and shutdown"

[stockhatch]

wdrzal, would I follow that method if I was charging my unit with R22 Freon?

Maybe I can answer this one. Yes and no. Yes to the methodology, no to purging with refrigerant. Use nitrogen insted(if you can get it) r22 is not something that should be vented :)

[wdrzal]

Charging: Since this is a small system and the refrigerant is propane charging will be done with vapor only through the low side port.connect yellow hose back to propane tank. purge air in hose as outlined before. both red and blue hoses should be connected to system. all charging from this point will be through the low side valve. the high side valve shall remain closed. even that the high valve on manifold is closed it will read system high side pressure. Open low side valve and let system fill with vapor.start compressor. the low side should drop and the high side should begin to rise. add refrigerant in small amounts into low side.let system run severial min.between adding so it stabilizes.put your hand on suction and feel to see if it is getting cold. Add refrigerant in small amounts until the suction line sweats(water droplets form) the whole way back to compressor. frost forming on suction is caused by liquid refrigerant boiling in the suction line.if you see this you over charged it.

walt

[wdrzal]

Hmmm, you say the valve should be closed, but it doesnt pull any vacuum with it closed...Its labled "intake", so I would assume it needs to be open. There is another twist valve labled "gas ballast" is that the one you mean should be closed?

EDIT: the unit also has on it to only open the gas ballast for "cold weather startup and shutdown"
yes the one gas ballast should be closed.

[wdrzal]

wdrzal, would I follow that method if I was charging my unit with R22 Freon?


jimi : yes exactly ;---the procedure is the same but not allowed to vent r-22 into atmosphere if in US.You must use a recovery machine until 27 inchs of hg is reached,then you can vacuum.

as pointed out earlier you can use nitrogen in betwen pump downs if you have it.

[wdrzal]

Sweet! Thanks again. How long can I wait before I charge since I dont have a fan for my condenser? Should I just charge till theres like 5PSI or so in there and wait till I get a fan to go any further? At least that way I could hook the hoses up later without pulling anything INTO the system.

you can put a initial charge in but without fan you will have pressure problems.

also I hope you ran pump long enough in between vac breaks. your pump will peg a manifold gauge 30 hg in 30 seconds.this dose not mean a deep vacuum was reached that quickly.

[Bloody_Sorcerer]

something like this thread should be stickied.

[stockhatch]

I ran it for about 25 mins between purges. I could shut the valve and it would maintain the pegged state if that means anything. I also ran it for like 30 minutes before the first purge. BTW, its cold :D Not sure how cold because I have no meter, but its cold enough to frost :D Yay fer me. Its cold and Im not blown up :) How does the frost line look? Too close to the compressor? Ill fine tune it via superheat/subcooling once I have a temp meter.

http://img.photobucket.com/albums/v46/stockhatch/getting_cold.jpg
http://img.photobucket.com/albums/v46/stockhatch/frosty.jpg
http://img.photobucket.com/albums/v46/stockhatch/frost_line.jpg
http://img.photobucket.com/albums/v46/stockhatch/running_pressure.jpg
http://img.photobucket.com/albums/v46/stockhatch/evap_frost.jpg

Thanks for all the help guys, Im stoked! :D :D :toast:

[wdrzal]

something like this thread should be stickied.

No: this was just a quick walk explaination taylored to stockhatches system and tools he had available.

[wdrzal]

IT works LOL sweat to the compressor not frost,theirs a differance.

[pythagoras]

Nice work Walt and stockhatch :toast:

[wdrzal]

it looks like you achieved about -32 f. not bad for a first run.

your pressures are off you need that fan.

[wdrzal]

if line is frosting that far back system may be overcharged,be careful,liqued returning to compressor can ruin it. Get that fan done.

[wdrzal]

hey stockhatch : have you figured out how I know the temp. you reached?

This is kool, I finially got something to work without getting my hands dirty :D :D :D

[pythagoras]

Well its definatetly between -28F and -34F so -32 is a damn good estimate ;)

[stockhatch]

I had a fan set up. BIG fan with plenty of flow. I just decided to use my shop fan to test it. How off are the pressures? Hehe, I guess I overcharged :D Like I said, Ill fine tune the charge later.

[stockhatch]

hey stockhatch : have you figured out how I know the temp. you reached?

This is kool, I finially got something to work without getting my hands dirty :D :D :D

Nope, havent figured it out. Im guessing that you are converting pressures to temps, but Im not sure.

[Jimi...]

So what's the right amount of pressure for R22 for lowest temperatures?

[stockhatch]

I've asked the same type of question jimi, and the answer I got was: There are no "right amounts" concerning pressures. It varies depending on several variables. :) I know, I hated that unspecific answer too :D

[pythagoras]

Okay,

The lowest pressure gives you the lowest temperatures, however the lower the pressure the lower the capacity. To determine the ideal, not necessarily lowest temp possible you need to look at a pressure enthalpy chart for r22.

Regards

John.

[wdrzal]

So what's the right amount of pressure for R22 for lowest temperatures?
lot more complcated than that,superheat needs to be worked out. cold vapor returning is great, cold liqued refrigerent returning will wipe out the compressor. You can not compress a liquid. walt

[wdrzal]

Nope, havent figured it out. Im guessing that you are converting pressures to temps, but Im not sure.

I just read the temp scale on your low side gauge(green one for r22) that gave me a quick idea. boiling point of propane is 2 degrees colder than r22 so gauges reads -32 you acually got to -34F. great job. Walt

[SoddemFX]

Excellent work stockhatch and excellent information wdrzal.

Reading this thread has been very informative :)

Tom

[Bloody_Sorcerer]

No: this was just a quick walk explaination taylored to stockhatches system and tools he had available.
then maybe something more "vague" and generalized? Also, I did say "something like"; I didn't necissarily mean this thread :p:

[stockhatch]

Walt, you mentioned my pressures being off. Can you explain to me what you mean and what I may do to fix them?

Thanks

[wdrzal]

first you need to get it set up with a load and a consistant air flow over the condensor before you can tune it. walt

ps: looks like that overlap joint on evap held. :D :D :D

[gkiing]

Leave the intake open to the air with teh pump isolation valve horizontal (open) turn it on, connect your manifold, vacuum till it hits 29.9 on the gauge on the pump or the lowest it can get to. A little tip for charging get a T connetor and put it on the charging inlet on your manifold, so you can have 2 hoses on the middle port. That way you dont need to purge the hose before you charge it and you can eliminate air from getting into the system.

[edit] saw you charged it.. nice job. It looks like its overcharged, insulate the suction line and then let out some gas through the high side until its running around 2" with nothing on the evap. If you have a thermometer tune it to 8degrees f superheat (temp 6" from the compressor is 8degrees f higher than the temp converted from the pressure on the lowside gauge).

[stockhatch]

Okay. Thanks for the tips. I guess the next thing to get would be a temp meter. Time to hit ebay :D

[wdrzal]

I forgot to mention a piece of insulation for suction line, be sure to get "closed cell foam." what are you going to use for the load? cpu or a peltier.whats nice about pelt is their is no chance of frosting up the mobo.And you can play with it on you desk. walt

[gkiing]

Okay. Thanks for the tips. I guess the next thing to get would be a temp meter. Time to hit ebay :D

Get a fluke 51 II or 52 II, you won't regret it. The 51's usually go for ~$70 and the 52's for ~$150

[wdrzal]

Anybody heard from stockhatck today? I hope his tongue isn't stuck to his evaporator and he can't reach the plug!!!. :D :D :D

walt

[stockhatch]

Oh I'm trolling about, dont worry :) Ive been trying to get this evap lapped. What a PITA that is turning out to be. Should have done it BEFORE brazing it to the system LOL. I also ordered a fan today. Going to start working on the enclosure I guess, though I dont want it to be too permanent as I plan to change compressors pretty soon.

[wdrzal]

make the shroud out of cardboard if its just temporary;of course you can't mount the fan to it. walt

[hatemi]

Cardboard and duct tape mate:D

[DGeNeRaT3]

Excellent Thread! I am nearly ready to assemble my single stage system and this has saved me from having to make my own "how do i charge my system" thread. All i need to do is make a trip to the refridgeration store to buy 2 dryers and braze up a few connections on the compressor and condensor and i will be at this stage, good help guys...thanks!

DGeNeRaT3

[stockhatch]

By housing I meant the case enclosure. I have a small shroud that will be better than nothing, and should bolt right up :)

http://img.photobucket.com/albums/v46/stockhatch/shroud.jpg

DGeNeRaT3, Im glad you find this thread helpful. I think its great to have some step by step guides for us n00bs :) Thanks again to wdrzal.

[wdrzal]

that shrould will work great! walt

[Jimi...]

I think I'm going to use Propane in my Phase Change. I've just been quoted £117 for 13Kgs of Freon. :eek:

[wdrzal]

Yea 134a has been going through the roof !!!

[Jimi...]

It's not really the price of the gas, it's more the price of the carriage.


Thank you for your enquiry received through our website. We have pleasure in quoting as follows:



1 off 13.6kgs cylinder R22 at £40.00



Carriage charge to Isle of Man £60.00



Total £100.00

Add VAT £17.50

Total £117.50



Please send us through your cheque and we can despatch a cylinder to you. This is hazardous cargo but we can complete the necessary documentation.



We await your instructions.



Regards

Sales Dept

R.A. Bennett Limited


That's the E-mail they sent me.

[gkiing]

Have you tried r22? It's really cheap here, about $65-$80 CDN for 30Lb + cylinder deposit

[hatemi]

That quote was for R22:)

[Jimi...]

Does anyone know if this Vacuum pump would be any good for charging Phase change units?

http://img54.exs.cx/img54/9123/speedivacpump8fu.jpg (http://www.imageshack.us)

The person who's selling it is asking £55 including shipping.

[Jimi...]

If anyone could let me know about the pump, it would much appreciated as I need to know today.

[kayl]

jimi you should start ya own thread dude :comp10: