Building Cascade ...A Walkthrough

The exchanger maxed out on me @ -43C (after 10min of work), probably would go further but the compressor heats up very much :\


Now i need some of Gary's help with tuning up the system, all i can remember were some sst and other stuff like that temps, pressures etc., could you post these shortcuts with a little note what they mean ? ^^

I know that pressures are 200 psi on the high side, a little vacum on the low side, -43C evap temp. the line next to the compressors accumulator is if i remember between 7 and 14C, ambient is 32C and the freon leaving the condenser is ~34-35C :o Post some more info when the compressor chills a little

I think that there's a curse on me... wich always lets me come very near finishing smth. but always makes it !F!U!C!K! UP!! so it doesent work... right now one of my shrader valves simply exploded, i unscrewed my service mainfol, wanted to seal with a cap and the moment i touched it- WHAM the valve shutted out letting all the freon go out.... Makes me wanna cry.... These are one of those moments wich make you want to leave it all alone...

These are the times that try mens' Souls......

Only the strong survive.

Hang in there.


Pops.

Ill survive but the problem is the incredible rage in me... If i wont let it out ill simply pop and do smth wich i wouldnt want to do..

i know the feeling, when i was finishing up my system this summer i found out that soldering doesnt cut it so i had to go back and redo all of my joints with 15% silver brazing alloy because i had about 10 leaks! it took me a long time to do and once i was done i found out that my manifold hoses leak too. the best thing to do is take a deep breath and think of the frost forming when you get finished :)

Ok, heres smth. really interesting for ya guys: how will i connect the injector to the evap ^^

Heres my thought path:

Orings wont stand -80C for 100%... What to do ?? Thinnk, think... What about flare fittings ? :o They will be great for such temps :o Ok, now how to change an injector sa i can connect flare fittings ?.. Hmm,.. Its made of steel so its very tough and will stand much.... So lets make some flare fittings in copper, female, treat the injector as it was a double male fitting and we get smth. like this:

Even dough it looks like crap it holds pressure :o Im gonna make a better prototype tomorrow

Welcome to the wonderful world of refrigeration. I have seen grown men cry (and throw things, break things, etc).

Take a deep breath, fix things as they break, and eventually you will get there. It's man against machine. Show no fear and never let the machine beat you. :D

One system is bad enough. Two systems (cascade) can really make you crazy. So what we need to do is forget that we have a low stage. Leave it off and forget that it exists.

Once you get the high stage going again, and down to its lowest interstage temp, we need to know:

Type of refrigerant used
High side pressure
Condenser air in temp
Condenser air out temp
Liquid line temp near condenser outlet
Low side pressure
Suction line temp near interstage outlet
Suction line temp near compressor inlet

R22
200psi
27C
30C
31-32C
~10psi
~ -32C

The system was VERY overcharged:

-30C on the acumulator

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Welcome to the wonderful world of refrigeration. I have seen grown men cry (and throw things, break things, etc).

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I always was a little O_o and refrigeration used to relax me but if i cant find a damn leak i get really furious...

Quote:

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Take a deep breath, fix things as they break, and eventually you will get there. It's man against machine. Show no fear and never let the machine beat you.

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It wont beat me but tomorrow i have to go with my parents on holiday (damn baltic sea) and there wont be any aftermatch tomorrow.... 2 weeks of sitting on the beach and tearing your hair of your head cause theres nothing to do.. And after all of this its payday, im buyng a new filter, a 13kg can of R22, 2-3kg. of R23, oil for R23, an oil separator and god knows what more ^^

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One system is bad enough. Two systems (cascade) can really make you crazy. So what we need to do is forget that we have a low stage. Leave it off and forget that it exists.

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I actually like it, its fun and its a great feeling when your temps fall down from the initial non calibrated system from -10C to lets say -35C ^^ And i think that calibrating my cascade will be very simple beacause i use electromagnetic car injectors wich i can digitally control so i have to only fill the system up so freon gets to them + some extra and all i have to do is get the proper steering frequency....

Condenser airflow is good. Relative condenser sizing is good. Your low side guage may be out of calibration. Does it read zero psi when open to atmosphere?

What makes you think the system is overcharged? I disagree. It is charged just right.

On changing the TXV orifice, we can't tell if it is right or not at this point. There is no need to change it until we see how it performs under load.

Haha then im very lucky ;] Or ive got a 6th sense ;]

Ive finetuned it a little, i get -40C on the exchnager and the temp goes down there very quick so it has a nice pull down... and during pull down the condenser gets really hot (it has 3 loops) and 2 of them (the outer tubes) have like 40C and the inner cools it a little more

So far so good. :D

What have you fine tuned? When you change something, you should take new temperature and pressure measurements so we can see what effect it has all over the system. Everything is connected to everything, and a change somewhere is a change everywhere.

Let some freon out ;] Just a little and pressures on the low side dropped but it goes down with the temps insanely fast comparing to what was earlyer, like 3-4x faster to -40C

The txv has a 00X orifice and its opened to the max, intill the screwdriver bends ;] Its rated for 200 or 250W @ -40C, how do you thing, is the flow through it sufficient ?

Some pics of the isolation im working on (didnt test it yet with this isolation cause its not finished)

Pipes

We need the complete list of temperatures and pressures to see what the system is doing. Don't worry about the orifice size for now. We are not going for lowest temp at this point. We want the charge right and the TXV setting right.

If you adjust the high stage system for lowest temp with no load, then when you start the low stage system, giving it a full load, it will not perform well.

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If you adjust the high stage system for lowest temp with no load, then when you start the low stage system, giving it a full load, it will not perform well.

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eeee ? :D

Didnt quite understand :D high stage = II stage, low stage = I stage ? :o

High stage = high temp stage = stage 1
Low stage = low temp stage = stage 2

could you drop in over here ?

http://polchat.pl/chat/?room=brqt

its a chat

Exchanger drying

Txv's bulb and the termometers probe

Finished the I stage

I would like to thank you guys for all your support, especially Gary for his help with calibrating the whole thing and Bowman for all the ideas and help

2nd pic of the I stage