pulling a vacuum

[shaun66]

every one seems to use a micron guage. i would guess that 90 % of resi contractors do not use one

i dont do resi, but that is what i have seen

[mark beiser]

I use the same setup that Mark does. With the ball valve at the sensor and stainless hoses.

Mark, without the ball valve between the sensor (in the picture), did you still open the valves or add refrigerant to the system with the sensor on the port?

I also have the same problem with the o-ring in one of their core tools. Looks like it's been chewed. I'll have to replace it before I use it again. Have you had better luck with C&D?

Before I put a ball valve in to blank off the sensor from the system I would break the vacuum to just a few psig with refrigerant, then remove the sensor and continue charging. I didn't go for very long without the ball valve though.
Having the ball valve on it allows me to just start dumping refrigerant in without having to worry about the sensor.

The C&D core removers have a double o-ring seal and a brass flare that seats against the service port. The o-rings die quickly, but the flare makes a really good seal if you put a little Nylog on it.
One of these days I'm gona order 1 of each brand of core removers and find out who makes the best ones.
So far I have only used the Yellow jacket ones, which suck, the C&D ones with a gate valve, which also suck, and the C&D ones with the ball valve, which work very well if you throw the o-rings away and put a little dab of Nylog on the flare every 2nd or 3rd time you use them.

[rogerk]

NOT using a micron gauge is like trying to measure 2" using your cars odometer.

[mark beiser]

I got a friend of mine good a few months ago. He was one of those techs that thought the evacuation was done when the pump didn't sound different when you closed the valve, and would argue passionatly about it.

I hooked up my vacuum gauge to a system he was working on, he had already decided the evacuation was done because his pump didn't change sounds when he closed the valve. The reading was around 10k microns. It wouldn't go any lower though, so we tried seeing how low his pump would pull just the gauge, it wouldn't go below 10k microns, even with an oil change.
I grabbed my pump and it pulled the gauge down to 40 microns, so we finished the evacuation down to 400 microns with my pump.

About 2 days later he bought a new pump and micron gauge. Just a cheep little colored LED light one, but its a start. I used one of those for years before I got my Yellow Jacket one, and it still actually works fairly accurately after 10ish years.

[desto1]

ditto what most have already said,i love micron gauges be cause nothing will show you any faster that there is a leak if you have one,no matter how small the leak.i use the 500 + 250 rule, vac to 500,if it doesnt rise above 750 after 35 t0 40 min,gas n go baby

[rickhall]

Look at the chart it will give you the obvious reason to evacuate. Especially in a heat pump, Ice-machine, and low temp refrig. That being said look at the boiling point of water at a 29" vacuum. With the refrigerant temp in the evap of a residential ac unit ,which is more forgiving than the previously mentioned systems, at 40 degrees design do you see what will happen ? HYDROCHLORIC ACID and Hydroflouric Acid. Look at the common denominator Hydro. Remove the hydro through evacuation and you remove future damage.

[square2round]

Before I put a ball valve in to blank off the sensor from the system I would break the vacuum to just a few psig with refrigerant, then remove the sensor and continue charging. I didn't go for very long without the ball valve though.
Having the ball valve on it allows me to just start dumping refrigerant in without having to worry about the sensor.

The C&D core removers have a double o-ring seal and a brass flare that seats against the service port. The o-rings die quickly, but the flare makes a really good seal if you put a little Nylog on it.
One of these days I'm gona order 1 of each brand of core removers and find out who makes the best ones.
So far I have only used the Yellow jacket ones, which suck, the C&D ones with a gate valve, which also suck, and the C&D ones with the ball valve, which work very well if you throw the o-rings away and put a little dab of Nylog on the flare every 2nd or 3rd time you use them.

I was very hesitant to put any pressure on the sensor. Although it sounds as if a few psig didn't hurt it.

I've got to look into another core remover also. There's gotta be something better.

[EarthLoop]

you came to the right place if you want to learn about pulling it..... and vacuum's.... we be experts at that stuff.

[howardair]

I do a lot of "res", ALWAYS use micron gauge. To me is is INSURANCE against call backs.

[hvaccop]

Pulling a vacuum with a micron gauge is a most. I bought the new Yellow jacket with the thermocouple. Best investment I have made in while. I micron gauge everything that my vacuum pump touches. Hook the gauge up to the system or inline with the hoses. If you hook up on top of the pump then you are reading the vacuum pumps capacity not the level in the system

[scottsacavsfan]

Pulling a vacuum with a micron gauge is a most. I bought the new Yellow jacket with the thermocouple. Best investment I have made in while. I micron gauge everything that my vacuum pump touches. Hook the gauge up to the system or inline with the hoses. If you hook up on top of the pump then you are reading the vacuum pumps capacity not the level in the system

Agree!

Everything I was ever told or read says place the micron gauge as far away from the vacum as possible
The best possible place is the evap I hear.
I dont do that
I use a 4 way gauge
3/8 to vac
1/4 to each service conection
and 1/4 to micron gauge
I dont trust my vacums ball valve ever

[technut]

I have always pulled from both sides and finished by pulling from suction port in the last few min. of vac.

[AirTechMech]

I have used a Thermal Engineering analog micron gauge for many years and just last year I bought a JB handheld digital and it seem so be a pretty good little unit. Anyone else have any opinions about the JB?