Bad schoeder valve on hose

[BrianA]

I Fixed the leaks in the line set and am vacuuming down. I have my Supco vacuum gauge in line with the pump. I get down to 485 microns, close my gauges and disconnect the hose from the pump.My micron gauge slowly goes up. I hooked my pump backup opened my gauge set and the system started out around 600. I think possibly the Schroeder valve is possibly leaking after I removed it from the pump. I had tested the lines with nitrogen at 150psi and it held fine for an hour.

Do you think it is safe to charge the system from the charge in the new compressor unit. I do not believe the lineset is leaking otherwise if I am not mistaken I would not have held the nitrogen pressure or got down to 485 microns

It seems to me that the hose may be the problem, not the line set.

What are your thoughts.

Brian

[BeaMage]

Im very inexpreienced at this, please forgive me.
When reading the nitrogen pressure the gauge is not that accurate compared to the vacuum reading of the micron gauge.
Could this actually be telling you that you have moisture in the system and still need to do more pump downs?

[BrianA]

When I pressurized the system with nitrogen It held 150psi on the gauge set.

My problem is when I vacuum down to 485 and close my gauge set and release the hose end from the vacuum pump (the Schroeder valve should hold the pressure) it slowly rises on the micron gauge. But when I hook the hose back up to the pump and turn it on and open my gauges the micron gauge reads 600. I think I have lost a bit of the vacuum from releasing the hose with a possible bad Schroeder valve. Other wise I am thinking the micron gauge would not read 600 if there is a leak in the line set.

I want to charge the system but not if there is a potential leak in the line set.

I am getting close to being able to apply to the Pro side :-)

Brian

[BeaMage]

Bear with me...
I have a 3 port gauge with two hand valves,
The middle hose if I'm not mistaken will not be of any consequence if both hand valves are closed.
Is this the same type of manifold gauge you have?
How could the yellow hose leak if the hand valves are closed?
If every time you unhook and hook up the pump you loose 115 microns its because of the hooking/unhooking. ?

[clearchris]

If you are talking about hoses with low loss fittings, they are exactly that "low loss". I haven't seen a hose with a schrader valve.

You have to purge the hose anyway.

[jpsmith1cm]

Couple things.

1> You will get deeper, faster evacuations if you lose the manifold, pull the schraeder cores with a valve core removal tool and use the largest hoses you can get your hands on. I use 3/8" diameter hoses.

2> Just change the core. They are cheap, quick and easy to change with a valve core removal tool.

3> PUT THE CAP BACK ON.

[BrianA]

Thanks guys.

Went with my intuition. Figuring that there must be no leaks. Started the system and is working fine.

Brian

[BeaMage]

You wanted no leaks.
We all need to go by science.
Science does not give a hoot about tuition.