Gray's New Cascade *56k Warn*

[Gray Mole]

The suction line heat exchanger looks just like this one, but the 3/8" suction connections are offset on this, cos it's for the Autocascade.



And it fits in just like this



It doesn't really add any size at all to the thing, just fits right in. The Low stage inlet is the partially insulated line comes from the desuperheater on the other side, and the one on the left is out to the HX inlet. I only armaflex taped the Low stage output from the SLHX, but I'll look at more possibly.

It's about 14" overall, 12" of that is 7/8" piping. The pipe is standard, so it's not as efficient as a proper HX, but it was pretty cheap to make. Just needs to be a little bigger to make up for it.

cont

 

[Gray Mole]

Ok, well this is how it went the first go...best temps just a short time running, I didn't get pics after running it for a while, but they were a touch higher, as I'd listed. After a while the ambient went up a bit to the ones I listed.

HX no load, just first stage running



HX second stage running, no load



cont

 

[Gray Mole]

HX second stage loaded



And the evap with the load tester on



I had a couple of problems when I came back to it though. The first stage was kicking back at me. I had the static pressure too high and had to back off on it. That meant retuning things on the High stage a lot, but I'll retest again this morning to make sure it's ok. I also had some oil slogging in the second stage. I think I just didn't have enough 290 in there. I added some, and then I checked it on load after the ambient came up to about 22 to 23 degrees. I had 2-3 psi Low pressure on the Low stage on load, and when I dropped it to 0psi the temps 'fell over', so I upped that to 4psi load to make sure I had enough capacity, though that cost me a little on temps as well.

I might retune the first stage completely if I still have some issues with it, but we'll see how it runs this morning. My pressures are about 6psi and 200psi on the High stage running, and that seems to be getting me about the best results but I don't like the discharge temps at all. I might change things.

cont

 

[Gray Mole]

New results after retuning, The ambient temp in the shed is quite high, about 23 to 25 degrees in there, so might gain a little when it's cooler.

HX with 2nd stage running



HX loaded on 2nd stage



cont

 

[Gray Mole]

New zero load temp on evap



Load temp on the evap



Not quite as good as the last run, but I had to change the charge on the 1st stage, and added some more 290 and upped the load charge for a little more capacity, so lost a degree or 2 on load.

I'm gonna see if I can't get the HX temps down a little, but we'll see. This might be as good as I can manage now.

Will let you guys know if it works ok this morning.

Gray

 

[fatty]

Very nice grey I pulled the twins apart yesterday and slapped them together in a small cascade setup but the temps where nothing to write home about I may mod the first stage up a little better as it was only hitting -20 therefor the second stage was only doing -45 ish so I am sure I can improve on the temps as I said I kinda just slapped it together lol

 

[scorchio]

Looking good nice to see you back posting at EP

 

[Gray Mole]

OK well final results are in, and you can tell me if you think they're ok

I put my lil cheapo DVM there to closely monitor air temps into the unit, so I'd know that I'm pretty close to what the real performance in a decently warm room would be. 22 ambient or close to it was the target, and when the unit's running and the halogen light is on, that's a real struggle. Open/close/open/close the door to keep the temps right.

When I started it this morning, it was ok, but I could hear the unit was struggling, still too high pressure, so I stuffed the idea of trying to frost the slhx, and just went for best hx temps. Got the pressure down to 4psi load on the high stage, which is a lot better, and my compressor ran cooler and discharge temps were lower, so I'm happy with that. I noticed the return from the slhx to the hx inlet for the low stage was sweating a little so I fully insulated that as well.

Well that's the new full load hx temp, and that was after a solid hour of running it. That temp stopped moving after about 15 minutes of load.



And the load temp of the evap. Still about the same, but the overall running is much better.



cont

 

[Gray Mole]

Both copressor tops were staying at about 60c or so, just about right.



I let the unit cool down with no load for about 10-15 minutes to see what the unloaded temps were now. What do you think?





cont

 

[Gray Mole]

I then simulated a 5min bench, just to see what it would be from no load to max load.





Lastly I wanted to see what the coldest no load was on the hx itself. Not bad at all.



So, -95 on a working R23 cascade. I'm pretty happy with that, and there's plenty of extra capacity over the load I'm putting on there, which is somewhere in between a Highly clocked Venice and X2 4800. I'm hoping there's enough for the X2, but I adjusted the charge on the last round to make sure I had a good buffer.

There's only one little thing. It took ages to get down to temps on the Low stage. There's something in my line. It was there before I changed over the the slhx, and is there now. I doubt it's moisture, I've been pretty good about vac/flush/vac etc, so I'm pretty sure it's not that. I vacced the Low longer than the high, and used the mapp torch each time to heat up the pipes to be 100%.

I think it's leaving oil behind when it's shut off. If that's what it is, then I'm not sure what I can do about it. Moisture wouldn't clear on a Low stage, and it's great once whatever's in there is gone. Took about 5 minutes for the temps to start dropping, and another 5 minutes for the temps to come down, but after that it didn't have any trouble at all as you can see. I'm gonna have a think about that, but if in the next couple days it get's any worse, I'm gonna pull the gas, replace the filter with a larger one rated for -50, and flush and vac the Low stage with both pressure and propane to make sure if there's any oil in there it's gone.

I guess it's just working so nicely now that I'm not all that inclined to mess with it anymore, but we'll see. If it just stayed the same, and there was a 10 min delay in using it, that wouldn't really be an issue, but I'm concerned it may worsen.

Ah well, it's running nice, and at least I know the High stage is 100%.

Cheers

Gray

 

[Gray Mole]

Hey fats good to hear you're still working on it. You can't really expect too much from the compressors, but if you use it to get your head round setting up the load on the base and Low stages, it'll really get you ready for your -100 monster later

Hey Scorchio Nice to be back, not that I've been around much, just spamming the phase thread lol

Cheers you guys

Gray

 

[scorchio]

Don't blame ya i think we are all interested to see the finished artical

Hey fats good to hear you're still working on it. You can't really expect too much from the compressors, but if you use it to get your head round setting up the load on the base and Low stages, it'll really get you ready for your -100 monster later

Hey Scorchio Nice to be back, not that I've been around much, just spamming the phase thread lol

Cheers you guys

Gray

 

[Gray Mole]

Well the new Chilly1 evap is on, and all together. I vacced it out today, and even found time to lap and polish the head. I noticed a very small ding on one side of it but it's off the IHS contact area, and it's polished in so it's not that bad really.

As I used the standard chilly mount this time, I could use standard insulation (justa hair thicker and larger than mach2 standard) and used the sleeving that I had, so it looks great

Currently charged and pulling -75 or so under my load tester. I had -77 but I wanted it charged a little heavier for more load. Pulled to -80 pretty fast, and to about -94/95 ish no load faster than before.

When I shut it off, the pressure return was faster so I think this is it, but I'll shut it down tonight and check it's working as it should tomorrow. Finger's crossed.

Pressures are running 1.5 PSI both high and low under load, so the pressures are matching, which is a really cool thing to see. -38 or better under load, and that's about 30-40 minutes while I made sure the charge was set the way I like it, and then hanging around for a while.

In other words, running sweet, and hopefully it's good from a cold start as well, then I can finally call 'er done.

Cheers

Gray

 

[fatty]

Very nice work mate I'm getting a chill thinking aboot it bring on the benchmarks I say

 

[Gray Mole]

Well the end result on this one is that after the longest and most complete vac cycle I've ever done it's still got a block of some kind at low startup temps, and it still clears as it did, and works as it should when it clears.

I'ts not gonna be moisture, but there's some oil or foreign goop or something that's in there.

It works, and I'm not gonna put any more time or money into it, but I can't sell it the way it is, and to fix it right would take a complete teardown.

So I'm gonna keep it. I know how to get it to work right, so I'll just have to box it up and use it for my own stuff.

I've got enough parts and such left to build the Autocascade with minimal stuff to buy, so I'll finish that, but I'm just too broke to get more parts I need for Cascading for a little while. I'll have to save up and get back to it when I've got the cash, and hopefully sell a couple other projects to get teh cashflow back.

'sides, I doubt I could sell this one for enough to warrant the complete rebuild.

The Autocascade should be quite pretty by comparison though, even if it's going to be quite a bit larger, and still be fun.

It's sort of a happy and sort of a sad ending I guess, as It's still a fully functioning cascade, and I ge to keep it for my own benching, it's just the fact that I can't seem to fix what's going on, and I just can't afford to keep trying at the moment. Other projects to do, and need to raise the cash.

Thanks to everyone for all the kind words and support, and once I've got a benching rig together I look forward to getting some scores again

Cheers

Gray

 

[fatty]

I found out what was stopping my cascade but its too late now as it killed one of my compressors but the beans inside the filter dryer came loose and went into the compressor noooooooooooo

I still have the baby twins to play with just cant find the time

 

[Gray Mole]

Your filter came apart?

I've never had that happen mate, that's weird. I'm really sorry to hear it. I ended up goin to solid core on my Cascade on both stages, and I guess I should be glad I did.

your bably cascade will do great things one day

Just remember it's all in the capacity of the HX and condensor, the compressors just determine the actual load temp, so unloaded you should still be able to get 10inHG working so you should still, on CO2 even, be able to at least see -90 in person or even colder, and on those little things, that'd be an accomplishment in itself

Gray

 

[fatty]

Yeah I just cant seem to spend the time on it

 

[scorchio]

Good luck hope it all goes well,we want pics