Were to go from here?

**[XC] mysticmerlin** · 05-18-2006, 11:50 AM

Originally Posted by n00b 0f l337

HEh the same quantity that goes out, goes back in. Or look up the specs of the compressor and find the oil charge (cc's)

Ok, I can handle that.

**[XC] MarioMaster** · 05-18-2006, 01:28 PM

i think i am going to make a chiller for my desktop, i have the thermostat from a refrigerator to keep the coolant right around the dew point so no condensation

**littleowl** · 05-18-2006, 03:03 PM

mario please take lots of pics and make a small work log when you do it!!!!!

**[XC] mysticmerlin** · 05-19-2006, 12:30 PM

Ok, So again
Is there a chart on here that lists the operating pressure of the gasses as I am not finding them. Like r-290 is ? on the high side and ? on the low side in operation?

**epion2985** · 05-19-2006, 12:44 PM

Depends. Even your high side can be in a partial vacuem. It depends on how much gas you charge you system with. It starts in vacuem and goes to infinity, or untill your pipes burst or your compressor craps out.

The question you should be asking is,

At (insert your condensing temperature) what pressure would be needed to condense the (insert your refrigerant)?

Also keep in mind the less refrigerant you have the less your capacity is.

Also keep in mind the more refrigerant you put in the higher the pressure will be, as the high side raises in pressure so will thr low side. The higher the pressure on the low side the higher the boiling temperature, ie the gas will be boiling at a warmer temperature, for instance instead of -50C it can go up to -10C.

The art of this is not really building the system but achieving the best ballance between there and alot of other factors.

For general information, on this forum, for these purposes, typical systems running typical refrigerants, with similar specs to propane run the high side around 140-200psi.

**[XC] mysticmerlin** · 05-19-2006, 12:54 PM

I guess that is what I am asking is if there is a "should be around ?-? as a starting point" list that some one has put together from all the posts on here.
Say like on a Mach1 (standard/no upgrades) regas what would you have on 404a vs the orig. 134a kind of chart thing is what I am asking. KWIM?

**[XC] mysticmerlin** · 05-20-2006, 06:33 AM

Ok, so I will start reading them all and try and put something together for us to use as referance. Or if you wall want to send me a couple pounds for each gas to put in the mach I will do it that way

This would be a great tool I think.

**[XC] mysticmerlin** · 05-21-2006, 05:00 AM

got a 2 stage 3cfm J/B pump off Flebay but 2 things
1. Lost the oil in shippment so what do I buy for it? I have air compressor oil
2. Gauges that came with it are r-22 and r-12 so will this read r-290 or 134a gas pressure?
This is why I asked for a range of pressures is because of this coming.
The price was right <95 shipped and it works excellent so what the hay.

**epion2985** · 05-22-2006, 01:36 AM

Originally Posted by mysticmerlin

got a 2 stage 3cfm J/B pump off Flebay but 2 things
1. Lost the oil in shippment so what do I buy for it? I have air compressor oil
2. Gauges that came with it are r-22 and r-12 so will this read r-290 or 134a gas pressure?
This is why I asked for a range of pressures is because of this coming.
The price was right <95 shipped and it works excellent so what the hay.

1. There is a guy on flebay that is popular as far as oil goes and many here buy from him, dont remember name though, ask jin. Or hvac supply house.

2. They will be fine for R290 or r134a. It seems the reference is more pressure related then substance related. Dont worry about it.

**n00b 0f l337** · 05-22-2006, 02:45 AM

1) Frosty Freeze is the name of the store.

**epion2985** · 05-22-2006, 03:03 AM

Originally Posted by n00b 0f l337

1) Frosty Freeze is the name of the store.

Thanks noob. Thats the one. He shipps incredibly fast and has an excelent reputation. Just make sure you buy the right oil for your pump.

**expansionvalve** · 05-22-2006, 04:24 AM

Originally Posted by epion2985

Depends. Even your high side can be in a partial vacuem. It depends on how much gas you charge you system with. It starts in vacuem and goes to infinity, or untill your pipes burst or your compressor craps out.

could you please expalin the conditions you have seen discharge pressure in a partial vac??

the only way i can see discharge line being in vac is either A, the unit is on a vac pump or B, the valve plates are shot in the compressor, never ever have I seen discharge running in vacuum, not even with no gas

**epion2985** · 05-22-2006, 07:19 PM

if there is trully no gas in the system and you pull a vacuum then yes your high side is also in a vacuum. I dont think the high side guage is meant to read well in the vacuum so its not a valid means of measure, not that you would need to, its simple physics.

**expansionvalve** · 05-22-2006, 10:45 PM

i still don't see what you are saying, i could possibly see it if you fitted a vac pump, pulled negative pressure and then switched the compressor on but anyother condition, id have to see it to beleive it..

**epion2985** · 05-23-2006, 12:07 AM

Thats what I said. If you have no refrigerant in the system or a small amount you can have both sides in a vacuum. And yes you need a vacuum pump to pull a vacuum, thats how its done lol...

**[XC] mysticmerlin** · 05-23-2006, 04:05 AM

Originally Posted by epion2985

And yes you need a vacuum pump to pull a vacuum, thats how its done lol...

LOL love it

**expansionvalve** · 05-23-2006, 06:45 AM

what a dumb response, please dont patronise me, i know how a vac is pulled with a pump, i have evacuated hundreds of units over the years a bit more advanced than these lego computer chillers.

to sum up my response.

the original question by mysticmerlin.

"Ok, So again
Is there a chart on here that lists the operating pressure of the gasses as I am not finding them. Like r-290 is ? on the high side and ? on the low side in operation?"

Above it asks for the operating pressure of gasses which I presume should be in normal cooling condition, you simply wont see discharge in negative pressure, he was asking for normal operating pressure, not running the unit in total negative state after vac pump...

**epion2985** · 05-23-2006, 08:00 AM

Originally Posted by expansionvalve

what a dumb response, please dont patronise me, i know how a vac is pulled with a pump, i have evacuated hundreds of units over the years a bit more advanced than these lego computer chillers.

to sum up my response.

the original question by mysticmerlin.

"Ok, So again
Is there a chart on here that lists the operating pressure of the gasses as I am not finding them. Like r-290 is ? on the high side and ? on the low side in operation?"

Above it asks for the operating pressure of gasses which I presume should be in normal cooling condition, you simply wont see discharge in negative pressure, he was asking for normal operating pressure, not running the unit in total negative state after vac pump...

...lol, well you had to ask.

operational pressures for r290 are around, high side 140-260psi, low side anywhere from 15" vacuum to 80psi. Thats just what typical here, you can go more or less in either direction.

well technically you can run with so little charge that your high side will be in a vacuum and its done sometimes. You will have really low temperatures but very very small capacity, sometimes thats what you need.

**[XC] mysticmerlin** · 05-23-2006, 08:11 AM

but is there not a spread sheet with information like this around?

**epion2985** · 05-23-2006, 08:16 AM

not that I have seen, probbably is somewhere. I would ask in the Vapor Phase Change Cooling section.

Hey how dare you take my quote out of your sig!! lol

**[XC] mysticmerlin** · 05-23-2006, 08:21 AM

don't want to start a pit fight in my own thread

**epion2985** · 05-23-2006, 08:48 AM

lol I was joking.

**[XC] mysticmerlin** · 05-23-2006, 08:59 AM

I know, it was good though.
"Chiller in progress" in your sig what's up with that?

**expansionvalve** · 05-23-2006, 09:06 AM

sorry to be so awkward epion, but...

[quote]
"well technically you can run with so little charge that your high side will be in a vacuum and its done sometimes. You will have really low temperatures but very very small capacity, sometimes thats what you need."

I really, really cannot see the high side being in a state of negative pressure under cooling condition.
You have gone from trying to tell me the discharge will be in a vacuum if the unit is 100% empty of gas, say after evacuating to 500microns and switching the compressor on, agreed, you may possibly see negative head pressure, but trying to tell me a unit running in the cooling condition, with a load, with gas, with negative head pressure??? i dont think so

**expansionvalve** · 05-23-2006, 09:22 AM

something else to think about,

take a bottle of refrigerant, it's charged with liquid, it's liquid because it's under pressure, let the liquid out of the bottle and the liquid turns to vapor due to not being compressed no more, the same is with the compressor, no head pressure, no condesnsing, no liquid, no cooling.... whats the point in that?

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