Pulling a vacuum....PROPERLY...

[energy star]

You know something about the Super Nova Sensor ?

BT you got this one ?

This has operating temps down to -30 to 150. This is nice. When it's 25 (f) out this may be more accurate.




The other one

This one along with superEvac have an operating temperature of 32 (f) to 120. Makes me wonder how accurate it may be at 32?


is +-10%

Gets cold here, many days under 32.

[beachtech]

You know something about the Super Nova Sensor ?

BT you got this one ?




The other one

is +-10%

both now, my first one was the second one you have posted and is prett ydarn accurate i can deal with plus or minus 10% when i am consistantly pulling down to 250-300 microns. even in this cold weather

[beachtech]

Please excuse me if this has already been covered here , but I have to ask ...Why is a digital meter prefered over an analog for measuring vacuum ? I've always thought it was the other way around ...but I've been wrong before.

here's what I use....

http://www.tif.com/products/detail.php?id=8252

I also have an old Thermal Engineering analog meter that always seems to " err on the side of caution " ( or is just hard to please ) when compared to some digital meters I've compared it with.

still the same thing. the only thing that has been digitalized is the display

[tech45]

still the same thing. the only thing that has been digitalized is the display

That's EXACTLY where I see the problem as well.

[beachtech]

well i don't see a problem with that lol

[derb]

I've used the Super Nova last week at work. I like the fact that the sensor and screen are seperate. I can put the screen where I can see it and just being the sensor seems to put less stress on the connection. Used it with the super evac kit and it seems to work great. Personally I've got the dv-22n and it seems to work fine, but I'm always wary of the connection. We had a shop dv-22n's senior go bad. Then again it seems like some of the guys in the shop can kill anything. We've lost 3 Micron gauges, nitrogen regulators, scales, tin snippets, recovery machines. Hopefully the Super Nova lasts a little longer. Think it was around a couple bills.

Dan

[joemach]

I've used the Super Nova last week at work. I like the fact that the sensor and screen are seperate. I can put the screen where I can see it and just being the sensor seems to put less stress on the connection. Used it with the super evac kit and it seems to work great. Personally I've got the dv-22n and it seems to work fine, but I'm always wary of the connection. We had a shop dv-22n's senior go bad. Then again it seems like some of the guys in the shop can kill anything. We've lost 3 Micron gauges, nitrogen regulators, scales, tin snippets, recovery machines. Hopefully the Super Nova lasts a little longer. Think it was around a couple bills.

Dan

Shortcoming I see is that it is not "full range" like the higher end Yellow Jacket.

I really like the full range feature instead of having to wait until it gets to about 9000 microns like some I have used.

[kew48]

In quickly reading this thread, I did not see any discussion concerning the need to always (not just the first two pulls) pull a vacuum on both high and low sides! In particular when there is a TXV installation. What you say?

[tostaos]

In quickly reading this thread, I did not see any discussion concerning the need to always (not just the first two pulls) pull a vacuum on both high and low sides! In particular when there is a TXV installation. What you say?

First there is not always a need to pull more than once. When you reach 200 microns, you reached 200 micron. You pull again and reach 200 microns, it's not any better than the first time. To me, it just makes sense to pull on both sides to speed up the process.

[jimj]

First there is not always a need to pull more than once. When you reach 200 microns, you reached 200 micron. You pull again and reach 200 microns, it's not any better than the first time. To me, it just makes sense to pull on both sides to speed up the process.

[kew48]

Agree --pull on both sides -- otherwise, if the TXV is a non=bleed type and valves off the liquid side, you may not get proper vacuum. Also can attach micro gage to the high side.

[acguytx]

id like to see more pictures of peoples vac set ups.

just got some new 3/8 hoses 2 i red one blue with 3/8 fitting on one end and 1/4 on the otherand 2 appion valve core removers. hopefully this will give me a tighter/quicker vac pull.

i have been setting up with one core remover on each side of system with cores removed and a 3/8 hose on the suction side directly to 3/8 vac port and the micron guage on the high side port so i have only been pulling from one side.. interesting about the txv and pulling from both sides..

maybe with two good large hoses i can put the other hose on the port on core remover and still have my mic gauge there as well?

I have been happy with my set up to date but i think my mic gauge, less then a year old, is leaking because when i isolate the old valve core by shutting it down from the system and shutting the rest of the system off from vac the micron gauge would start rising fast.. i was thinking its leaking or the core remover( old c&d), old JB was the issue hence i bought a bunch of new stuff and cant wait to try it out.

I guess if it still rises when i isoalte it i have a defective mic guage and need toi send it back..

[CrispinHvac]

if you only pull on the suction side and you have your micron gauge on the liquid line and if you can get it down to 500 microns and the rise is minimal then woudent that be ok?

I have always wondered if you could just pull a vac from the suction side with a txv.

now with the scroll compressor and lets say a non bleed txv wouldent the scroll compressor act like the bleed ?

or maby im confused ?

im not sure lol

[kew48]

If you're pulling from just the suction side and with your Micron gage on the liquid side and reading 500 microns,you should be OK-even with a TXV. Regarding the scroll compressor, many times after a pull down for an evap changeout, your compressor is valved out of the loop when pulling a vac.

[bldgcode1]

I just saw another thread where it said you can't pull a proper vacuum without using a micron guage. Does the guage somehow make the pump pull a better vacuum? Or is the guage really just letting you observe what your proper practice procedure is doing?

[jpsmith1cm]

I just saw another thread where it said you can't pull a proper vacuum without using a micron guage. Does the guage somehow make the pump pull a better vacuum? Or is the guage really just letting you observe what your proper practice procedure is doing?

You MAY be able to pull a proper vacuum without a micron gauge, but you will never be able to verify that vacuum without the gauge.

[marvin]

very well said jp

[hvacrmedic]

if you only pull on the suction side and you have your micron gauge on the liquid line and if you can get it down to 500 microns and the rise is minimal then woudent that be ok?

I have always wondered if you could just pull a vac from the suction side with a txv.

now with the scroll compressor and lets say a non bleed txv wouldent the scroll compressor act like the bleed ?

or maby im confused ?

im not sure lol

When you pull a vacuum on the low side the TXV will throttle open, providing that it isn't defective. The forces acting on the seat are bulb pressure, suction pressure, and spring pressure. The bulb provides an opening force while the spring and low side pressure provide a combined closing force. So the TXV can only be closed when the sum of the low side pressure and spring pressure are greater than the bulb pressure. There is no issue with the compressor, you'll be pulling from the compressor case directly through the suction line, and from the discharge side through the suction line, evaporator coil, liquid line, and condenser coil. It's a long path, but those molecules are moving around at the speed of sound, so no problem.

[bldgcode1]

JP - That is/was my point. I have never changed my procedure for pulling a vacuum. The Micron guage simply displays that what I was taught and have done for the last 38 years is one of the correct processes. But I am getting tired of people saying that the Micron Guage is what "allows" the proper vacuum to be pulled. It simply displays that a proper vacuum has been pulled. If you don't use one, you simply can't prove what you've done.

[Tech Rob]

Here's how it's done...