manifold valves and gauges question

[PoorOwner]

I am looking into how the knobs work on a manifold, but I am a bit confused by this picture that shows on one of the manuals, with the valves closed, will the gauges still read anything like the picture instruct to do?

I thought you would have to open the A and B valves for the gas to go into the manifold and thus making the gauges read the pressures

 

[Jeepster04]

From what I understand, you only open the valves to pull a vacuum or add refrigerant.

 

[zmaxmotorsports]

From what I understand, you only open the valves to pull a vacuum or add refrigerant.

Yes.

 

[LS6 Tommy]

The manifold is a plenum. The valves isolate the individual hose ports from the plenum. The gauges are always open to the high side and low side ports to the hoses you hook up to the service valves on the compressor. "A" is the "low" side "B" is the "high" side. "C" is the vacuum port. "D" is the refrigerant port.

Tommy

 

[PoorOwner]

The manifold is a plenum. The valves isolate the individual hose ports from the plenum. The gauges are always open to the high side and low side ports to the hoses you hook up to the service valves on the compressor. "A" is the "low" side "B" is the "high" side. "C" is the vacuum port. "D" is the refrigerant port.

Tommy

Thanks for the explanation. So for example I need to isolate a nitrogen psi test or vacuum hold. What I have to do is close “A” and the gauges and blue hose will be the only thing connected to the system.

I guess using red gauge and a hose from that side will accommodate higher psi test though.

Mini split don’t have the high side service port at least not in plain sight, so “B” will just be kept closed.

 

[bobbyjean]

you need to pull a vacuum on line set...the hose's are going to be good for either 800 or 1500 psi...you should be nowhere near that with nitrogen
if your flaring copper..try nylog...have had great luck with it