I've been doing a lot of vacuums lately and thinking about them too. This topic comes up here many times but I think it's worth repeating many times and I'm doing it here in the tech-tech section so it can have more views and hopefully get to some of the newer guys as well.
When I first started in HVAC(7 years ago) the ball was already rolling on the use of micron gauges and pulling below 500 microns but that was it, you would see micron gauges in the parts house, hear techs make references to them or getting the microns low but nobody I was around seemed to know how best to use these tools or how to duplicate good results, there was a lot of "mysticism" or "magic" involved it seemed. There were a lot of techs who used a micron gauge, one or two times, had poor results and abandoned it all together.
Then there were a few guys, including myself, who were constantly messing around with their setups trying to figure out a way to make it work, have repeated success, figure out the issues that were holding us back because we believed it was possible but no one could show us a better way. For the most part I think the vast majority of techs in America still fall into one of three categories:
1. Don't use a micron gauge but know about their existence
2. Used a micron gauge, got frustrated, gave up
3. Currently use a micron gauge, trying to figure it out, feel like they are probably the only ones who try and wish they could figure out a better.
Well, you can have a good vacuum setup, use a micron gauge and have repeatable success. I'm going to list what you have to do and then show you my setup(same as many here) that you don't have to have but I think it's good and does a great job.
You have to have:
1. A decent micron gauge, my recommendation is the BluVac or UEI version.
2. A way to blank off the pump from the system with the micron gauge still reading the system. Pulling a low micron reading with the pump doesn't mean much other than your gauge works, the blank off test isolates the system and allows the micron gauge to read the real micron levels in the system.
3. Obviously a working pump but also vacuum pump oil that can handle the job, I don't mean a brand here but rather how clean is that oil? Do you have the same oil in your pump from may-September? I've literally worked with guys who did quarterly oil changes, that doesn't cut, I've had to change fresh oil out on the same system I've started on because it became moisture saturated and couldn't pull the system down anymore.
That's all that is "required" beyond that a 500 micron vacuum is a 500 micron vacuum but there are ways to reduce time and reduce frustration, here's how:
1. Less is more, the fewer the connections the better because there are fewer places to leak and slow you down. My set up has two hoses, straight to CRT's(core removal tools) and my blank off test only has four possible leak points.
2. Bigger is better, you have to hook up to 1/4" ports(except on mini's and VRV) but larger hoses from there back equates to shorter vacuum times.
3. Remove restrictions, have you looked at a schrader core? Not much of an opening right? Get them out of there. How about schrader depressors in your hoses? Pretty small opening right? Get them out of there. Full bore opening vacuums cut time.
So with that said here's some pics of my set up that straight up dominates my co workers in head to head matches.
Pump and hoses(I'm going to save up money for a new pump but even the bullet is vacuuming like a champ with this set up)
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2 appion CRT's
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BluVac gauge, notice the valves are closed with no hoses hooked up, just to show I'm not cheating : ).
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After 5 minutes blanked off, if it doesn't rise at all or goes down a little I call it good unless its a really big system, if it rises some ill give it another 5 minutes.
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Heads up match my setup versus old school style on two 15ton circuits
Pictures in next post...
When I first started in HVAC(7 years ago) the ball was already rolling on the use of micron gauges and pulling below 500 microns but that was it, you would see micron gauges in the parts house, hear techs make references to them or getting the microns low but nobody I was around seemed to know how best to use these tools or how to duplicate good results, there was a lot of "mysticism" or "magic" involved it seemed. There were a lot of techs who used a micron gauge, one or two times, had poor results and abandoned it all together.
Then there were a few guys, including myself, who were constantly messing around with their setups trying to figure out a way to make it work, have repeated success, figure out the issues that were holding us back because we believed it was possible but no one could show us a better way. For the most part I think the vast majority of techs in America still fall into one of three categories:
1. Don't use a micron gauge but know about their existence
2. Used a micron gauge, got frustrated, gave up
3. Currently use a micron gauge, trying to figure it out, feel like they are probably the only ones who try and wish they could figure out a better.
Well, you can have a good vacuum setup, use a micron gauge and have repeatable success. I'm going to list what you have to do and then show you my setup(same as many here) that you don't have to have but I think it's good and does a great job.
You have to have:
1. A decent micron gauge, my recommendation is the BluVac or UEI version.
2. A way to blank off the pump from the system with the micron gauge still reading the system. Pulling a low micron reading with the pump doesn't mean much other than your gauge works, the blank off test isolates the system and allows the micron gauge to read the real micron levels in the system.
3. Obviously a working pump but also vacuum pump oil that can handle the job, I don't mean a brand here but rather how clean is that oil? Do you have the same oil in your pump from may-September? I've literally worked with guys who did quarterly oil changes, that doesn't cut, I've had to change fresh oil out on the same system I've started on because it became moisture saturated and couldn't pull the system down anymore.
That's all that is "required" beyond that a 500 micron vacuum is a 500 micron vacuum but there are ways to reduce time and reduce frustration, here's how:
1. Less is more, the fewer the connections the better because there are fewer places to leak and slow you down. My set up has two hoses, straight to CRT's(core removal tools) and my blank off test only has four possible leak points.
2. Bigger is better, you have to hook up to 1/4" ports(except on mini's and VRV) but larger hoses from there back equates to shorter vacuum times.
3. Remove restrictions, have you looked at a schrader core? Not much of an opening right? Get them out of there. How about schrader depressors in your hoses? Pretty small opening right? Get them out of there. Full bore opening vacuums cut time.
So with that said here's some pics of my set up that straight up dominates my co workers in head to head matches.
Pump and hoses(I'm going to save up money for a new pump but even the bullet is vacuuming like a champ with this set up)
2 appion CRT's
BluVac gauge, notice the valves are closed with no hoses hooked up, just to show I'm not cheating : ).
After 5 minutes blanked off, if it doesn't rise at all or goes down a little I call it good unless its a really big system, if it rises some ill give it another 5 minutes.
Heads up match my setup versus old school style on two 15ton circuits
Pictures in next post...
