EVACUATION

Evacuation

Vacuum Hoses

Valve Core Removal Tool

• Visible Moisture

– Water Droplets

– Uncommon, but it can occur

• Invisible Moisture

– Water Vapor

– Found in all gasses

– Found in all solids

Moisture In A Refrigeration System

• Freeze Ups

– Ice crystal formation will occur at the point of expansion, i.e.:

• Capillary Tube

• TXV

• Flow Rator

• This problem will be intermittent

– When the system warms up the problem stops

Visible Moisture Problems

• Air in the piping

• “Wet” Refrigerant

• Leaks Under a Vacuum Condition

• Copper and Brass Components

• System Components exposed to the atmosphere during assembly

Invisible Moisture

Moisture + Refrigerant Acid

Moisture & Refrigerant

• CFC & HCFC & HFC Hydrolyze to form Hydrochloric Acid

Hydrofluoric Acid

• Acid Formation Is Accelerated By Heat

• Copper and Brass Will Be Attacked Plates Hot Surfaces

Bearings Seize

Moisture & Refrigerant

Sludge

Metal + Refrigerant + Acid + Oil

Moisture & Refrigerant & Oil

• We boil it

• We can’t raise the system temperature to 212°F

• So we have to lower the system pressure to A point where water boils at ambient temperatures.

So How Do We Get The Water Out?

Each Mark Represents 2” of Mercury Column

Or 50800 Microns

How Is Vacuum Measured?

Displays pressure in microns in steps of 1 micron. Has pump down indication showing progress from atmospheric pressure.

• Range: 50 to 2000 microns of mercury. • Resolution: 1 micron of mercury. • Pump down indication: when pumping down from

atmospheric pressure to 2000 microns, output of head goes from over 3VDC to 2VDC.

• Straight-in access to sensor for easy cleaning. • Fitting: 1/4" flared brass fitting (male) . • Accuracy (@~75ºF): ±10%, 0-1000 microns of

mercury. • Auto-off can be disabled for data logging. • "T" for inline vacuum testing.

How Is Vacuum Measured? Other Tools of the Trade

250 Microns

Evacuation With Micron Gauge

• Vacuum pumps are rated in cubic feet per minute of free air through the pump

• As a rule of thumb 1 CFM per 7 tons of system is adequate I.E. A 6 CFM rated pump will be good for 42 tons of

system capacity

• Multiple pumps are OK

How Much Pump Do You Need?

Evacuation

ALL pipe work must be insulated along its full run using 3/4” Wall Insulation (Armaflex etc).

The liquid line must be insulated in unconditioned space in a long lineset application

Could cause excessive subcooling.

Insulating