51 Seconds to 500 Microns

[270wsm]

Is it worth the extra bulk and stiffness to go with the 1/2" hoses over the 3/8" hoses??? 3/8 is a huge improvement over 1/4". Not sure if 1/2 would be enough advantage over the 3/8" to justify the added bulk.

[eddiegoodfellar]

Is it worth the extra bulk and stiffness to go with the 1/2" hoses over the 3/8" hoses??? 3/8 is a huge improvement over 1/4". Not sure if 1/2 would be enough advantage over the 3/8" to justify the added bulk.

Depends on what size equipment you are working on.

[270wsm]

Mostly 5 to 15 ton. And I use a 6 CFM pump.

[jim bergmann]

Mostly 5 to 15 ton. And I use a 6 CFM pump.

1/2" For sure they are much faster than 3/8" I only use my 3/8" hoses for recovery.

[270wsm]

Ok so I'll go with the 1/2 inch hoses. Are 6' lenghts optimum, would going with shorter be better? Also, which 1/4 ends do you recommend, the straight or 45°?

[jim bergmann]

Standard 6' with straight fittings is what I use. It is a nice length that is easy to work with.

[270wsm]

I noticed my 3/8 brass tee doesn't really have a full 3/8 bore. Barely over 1/4 I.d. Are they all like that??

[jatinder.bhargav]

i am using 8 CFM vacumm pump & trying of vacummizing my 8.5 Tr unit having internal volume of around 1.8 cu.ft

Ideally what should be the vacummizing time?? it is taking so long (around 7-8 hrs) to achieve 400 microns even.

[jim bergmann]

I noticed my 3/8 brass tee doesn't really have a full 3/8 bore. Barely over 1/4 I.d. Are they all like that??

Yes most are like that, however, it is the hoses that make the difference much more then the fittings. The hose creates a lot of friction that slows the evacuation. Flow is much different in a vacuum then in pressurized applications.

[jim bergmann]

With the right hoses and the right process, i would guess less than 1 hour for sure. If the refrigerant is still out-gassing from the oil, it may take a bit longer, but not much longer than that,

[ComfortService]

Is this really necessary though? I just put my regular gages and pump on every system I do and then do some other aspect of the install and come back to my pump and gage later, and it is always ready for me at below 500 microns and I have no wasted time of additional initial setup or the added expense the having to buy this kit.Anyone?

[mark beiser]

Is this really necessary though? I just put my regular gages and pump on every system I do and then do some other aspect of the install and come back to my pump and gage later, and it is always ready for me at below 500 microns and I have no wasted time of additional initial setup or the added expense the having to buy this kit.Anyone?

On a new residential split system install, where you are just evacuating a linset and coil, it is usually massive overkill, especially with new copper lines.
On repairs, where you have to evacuate the whole system, the time savings are very significant. A good evacuation setup can cut the time down to less than 1/3 the time it would take using your normal service manifold and hoses.
On a large commercial system, you can save hours with a good evacuation setup.

[jpsmith1cm]

On a new residential split system install, where you are just evacuating a linset and coil, it is usually massive overkill, especially with new copper lines.
On repairs, where you have to evacuate the whole system, the time savings are very significant. A good evacuation setup can cut the time down to less than 1/3 the time it would take using your normal service manifold and hoses.
On a large commercial system, you can save hours with a good evacuation setup.

I was thinking along these lines.

If all that you do is new installation, then you could get away with just using a manifold by scheduling your work so that the pump has the maximum time to run. It isn't really the correct way to do it, but it would suffice.

As Mark mentioned, though, there is more to the world than installing residential equipment. Sometimes, you're running a service call, replacing a compressor or even working on a larger system.

I've switched to using 3/8" diameter hoses for pulling vacuum and, sometimes, I still work that old rhythm of install pump, fire it up, do the wiring, clean up my tools, set up the micron gauge, etc... It doesn't take that long, but when you're pulling a vacuum on freezer with a 2 5/8" suction line that's a couple hundred feet long, every bit of volume counts.