"Right" is not the same as "Wise".
Don't step on my favorite part of the Constitution just to point out your favorite part.
Just because you can measure it, doesn't mean it is important. Just because you can't measure it, doesn't mean it isn't important.
I know this has been said so many times, but all I always hear is. why go threw all the trouble knowing you going to be back any how. Im like dude. have you lost you mind. why would you like to come work on this more than one time and look like a fool. the answer is doesn't bother me. well I too was told to just pump it for 15 min and wait for the pump to change sound. now maybe in the beginning when I started I did that. but after seeing change I do change! insanity is doing the same thing over and over and expecting change. well im into new things. I own all digital gauges, i use a appion mega flow kit and also a appion 8cfm pump. it used to take hrs to do a simple vac down with 1/4 hoses and a manifold. I do pump downs in less then 7 minutes now with my 1/2 hoses. I pull down to like 125hg in like 5 min. its insane to see how fast it is. so many videos proving the setup is sound. its the techs who really don't care that won't change. or want to learn something new
Well, in theory, if the vacuum gauge is not within the manifold, and is a seperate sensor, ie. Testo and YJ, then you could hook up to CRT's with the vacuum gauge and hoses. When you test the system, simply valve off the CRTs and watch the vacuum. Then when ready, open the CRTs and go for it. It doesn't matter whether the vacuum is read by a stand-alone gauge such as the BluVac, or a seperate sensor on a manifold, as long as the manifold is valved out of the system during standing vacuum test, then you're good to go.
The only time it becomes a problem is speed, using a manifold, just increases the area to vacuum, and a lot of techs don't use larger hoses, so it takes longer to vac a system. I'd rather use a seperate vacuum kit and not a manifold.
Manufacturers make what they think will sell, and if it's another feature that adds value and technically not wrong, then they'll add it.
As many others have said you can pull a vac through a manifold but it is more time consuming and their is a greater chance for leaks. Using a manifold you have the restriction of the core depressors and the 1/4 hoses. When pulling a vac through a manifold I have had hose gaskets leak, hose crimps leak, valves on the manifold leak, gauges leak, and fittings on the manifold leak. Also the standard RYB hoses can permeate. When I pull a vacuum I use Appion Megaflow hoses 3/8 on one and 1/4 on the other hooked directly to the pump and CRTs. I pulled and 15 ton circuit down to 194 microns today in less than an hour. I isolated the pump and after 30 minutes the system rose to 253 microns.
My question is: Why would you even want a manifold? On 80% of my installs (commercial refrigeration and A/C) I use the Appion valve core removal tools, large hoses, and a pump. When Im down to a good vacuum, I let the charge fly and disconnect. Done.
Oh sure, maybe Ill put a manifold on and check pressures, S.C., S.H., but during evac, why would I want a manifold?
If God didn't want us to eat animals... He wouldn't have made them out of MEAT.