Mastering Decay Testing With BluVac 3.0

[@vincentsearle7064]

Would like to see a video of all of Jim's tools

[@mikerefrigeration5736]

Can you make a video about pulling vaccums for service technicians? I feel like a lot of repairs done for refrigeration or compressor replacements causes refrigerant off gassing and it affects the microns gauge and decay test. What is an acceptable vaccum if you're replacing the refrigerant and filter drier? Just a followup to my initial question: If one were to replace a evaporator coil on a walk in cooler or freezer and the condensing unit is 10 years old, what should the goal of evacuation be? Also should suction line filter driers in conjunction with a deep vaccum be a consideration? It would be interesting in seeing jim explaining basic filter drier selection.

[@dylb8801]

I highly agree more service worn tha clean fresh install stuff. So us service guys can get a idea of what's left over refrigerant boiling off and leak for say

[@Andersonairchris]

I would love that too but its really hard to define what's "good enough" for a system that's got used copper, coils ect that have oil in them which is impregnated with refrigerant.

[@dylb8801]

@@Andersonairchris the whole reason Jim can give us a rough idea what to look for

[@coldfinger459sub0]

Thank you for more detailed fine-tuned explanation. Much needed information.

[@superiorcomfortheatingairl3373]

My BluVac pro always passes decay test within 10 seconds on a new install after isolating, but when doing a repair on entire operating system (condenser, line set & coil) it passes the decay test but shows on the a graph chart and with the parameters I set should not of passed. I trust this gauge on new installs, but do get different reading compare to other micron gauges on repair type situation

[@horsth9566]

Does this “One hose” demonstration take into account “restrictions” such as the orifice, piston or txv, and the filter drier plus the compressor? Should a much higher micron level be expected and or a much longer time period to achieve the expected results?

[@measureQuick]

@@horsth9566 it does taken into account the metering device. If you’re doing a full system, including the condenser coil and compressor, it is going to take longer. A big factor and that is how dry the system was during the initial evacuation. Typically, we recommend a target of 500 µm with the decay no more than 1000 µm. The dryer should be replaced and the moisture with the dryer. Many times I’ll also install a moisture indicator to make sure that the system is dry after 24 to 48 hours.

[@horsth9566]

Thank you so much Jim. You’ve earned my utmost respect for your knowledge and for the commitment to the industry. You are an example of reaching for higher standards and sharing your experience for the benefit of so many.

[@cm9368]

what's going on when you isolate the system and instead of getting that positive curve on the chart your micron levels continue to drop?

[@measureQuick]

@@cm9368 it was a slow close, so trapped gas burped out and it continued to drop until it was completely closed.

[@jharrison6557]

So i guess the only way to tell the difference between decay and a leak is how fast it levels off??

[@measureQuick]

@@jharrison6557 A leak will have almost a constant rate of rise, moisture will eventually level off in the Leak rate will go down to zero

[@HVACR559]

Water will reach a pressure tempature it stops evaporating / boiling. This is why the micron guage stops rising below 2000 µm If there is a leak in the system it will rise to very near atmospheric pressure If we are serving an existing system the refrigerant in the oil will make it look like a leak. It is likely refrigerant boiling off in the compressor and accumulator. Given enough time the pressure may rise to a positive pressure in that case. This is why pressure testing is very important on existing systems. When servicing an existing system It may more than an hour to get a system pulled down to 1000 µm. Don't know if Jim agrees but I will sometimes call it at 1000 µm, I'm well below 1500 µm so I have most likely removed most of the non-condenseables and the constant flow of refrigerant towards the vacuum pump should have removed most of the moisture. If an existing system will fall down to 300 µm or so I will let it ride till it hits a plateau.