hvacr318 refrigeration ii n.
Skip this Video
Loading SlideShow in 5 Seconds..
HVACR318 – Refrigeration II PowerPoint Presentation
Download Presentation
HVACR318 – Refrigeration II

Loading in 2 Seconds...

play fullscreen
1 / 39

HVACR318 – Refrigeration II - PowerPoint PPT Presentation

  • Uploaded on

HVACR318 – Refrigeration II. Charging Refrigerants. Charging Defined. Charging a system is to add or replace refrigerant in a system. Refrigerant is never used up. It either leaks out or it is contaminated by: Water Acid Noncondensibles . Charging Refrigerants - Methods . Weighing

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'HVACR318 – Refrigeration II' - eros

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
hvacr318 refrigeration ii

HVACR318 – Refrigeration II

Charging Refrigerants

charging defined
Charging Defined
  • Charging a system is to add or replace refrigerant in a system.
  • Refrigerant is never used up. It either leaks out or it is contaminated by:
    • Water
    • Acid
    • Noncondensibles.
charging refrigerants methods
Charging Refrigerants - Methods
  • Weighing
    • Using scales to check the amount added
  • Measuring
    • Using a dial-a-charge cylinder
  • Superheat and Subcooling
    • Most accurate
    • Combine with weighing in the charge.
    • Allow system to run for 10 minutes before taking readings.
charging refrigerants methods1
Charging Refrigerants - Methods
  • Sight Glass
    • Never used to check the charge
    • Not accurate
    • Varies based on system conditions
  • Amperage or Wattage
    • Not accurate at all
    • Do not use unless you have no other options.
states of refrigerant charging
States of Refrigerant Charging
  • Refrigerant can be charged as a:
    • Vapor
    • Liquid
vapor charging overview
Vapor Charging - Overview
  • Entails taking vapor refrigerant out of a refrigerant drum and putting it into the low side of the system.
  • If the system is not operating, you can add vapor to both the low and the high side of the system until the pressures equalize.
vapor charging1
Vapor Charging
  • If the system is running, add vapor to the low side ONLY.
    • High side is under a higher pressure than the drum.
    • Opening the high side on a running system can put too much pressure on the refrigerant cylinders and cause them to explode.
vapor charging3
Vapor Charging
  • In some cases, the refrigerant drum may be cold and cause it to have a lower pressure than the low side of the system.
    • Warm up the drum or the cylinder.
      • Warm water bath
      • Heater blanket
vapor charging advantages
Vapor Charging - Advantages
  • Advantages
    • Easiest way of adding refrigerant to top off a running system.
    • Liquid refrigerant cannot enter the suction side of the compressor. Vapor is allowed.
vapor charging disadvantages
Vapor Charging - Disadvantages
  • Disadvantages
    • Slow process for adding large quantities of refrigerant.
    • High drum pressures can force oil out of the compressor.
    • Blended refrigerants may fractionate (or separate) as they are charged.
liquid charging overview
Liquid Charging - Overview
  • Entails adding refrigerant in the liquid state into a system.
  • In a non-operating system, you can add liquid refrigerant through the king valve on the receiver.
    • King Valve = Service Valve.
liquid charging
Liquid Charging
  • On an operating system you can front seat the king valve.
    • Jump out low pressure control
    • Be careful not to overcharge
liquid charging3
Liquid Charging
  • Liquid charging on an operating system through the low side:
    • Must be careful
    • Experienced technicians only
    • Flooding may result
liquid charging4
Liquid Charging
  • There are commercially available charging devices for charging liquid in the suction line; it acts like a metering device.
    • If the compressor becomes cold or frost starts to develop, stop charging with a liquid. Let it boil off.
liquid charging advantages
Liquid Charging - Advantages
  • Advantages:
    • Fast
    • Convenient (through low side)
liquid charging disadvantages
Liquid Charging - Disadvantages
  • Disadvantages
    • System may have to be turned off
    • Easy to overcharge
weighing refrigerants overview
Weighing Refrigerants - Overview
  • Usually accomplished using various scales: Dial, Electronic and Electronic Charging Scales.
    • Dial Scales
      • Can be difficult to use and inaccurate.
      • Set the charge on a dial and the scale shuts off when complete.
      • Not digital, and have faded from popularity.
weighing refrigerants
Weighing Refrigerants
  • Electronic Scales
    • Portable
    • Less Expensive
    • Accurate
    • You cannot walk away and allow charging to occur without youthere – must watch scale.
weighing refrigerants1
Weighing Refrigerants
  • Electronic Charging Scales
    • Combination of electronic scale and old ‘dial-a-charge.’
    • Accurate
    • Automatic
measuring refrigerants overview
Measuring Refrigerants - Overview
  • Graduated Cylinder
    • Dial-A-Charge
    • Put refrigerant into cylinder up to the line and then charge the system.
    • Not used much anymore, as they are not safe.
    • Tech must handle liquid refrigerant.
steps to charge
Steps to Charge
  • Make sure system is in a vacuum and do not remove gauges.
  • Connect cylinder to the small center hose on the manifold.
  • Open refrigerant cylinder
  • Purge the air out of the center line.
steps to charge 1
Steps to Charge 1
  • Open the center manifold valve and allow the refrigerant into the charging manifold.
  • Decide on low or high side charging.
  • Place the cylinder onto the scale and zero the scale out.
  • Open the high or low side valve on the manifold and weigh the refrigerant in.
steps to charge 2
Steps to Charge 2
  • While charging system, watch amperage of compressor.
  • If amperage goes above FLA (Full Load Amperage) shut off valve and wait for the amperage to stabilize and drop.
  • Never walk away from a unit while charging system.
steps to charge 3
Steps to Charge 3
  • Once system is charged, check superheat and subcooling prior to removing the gauges.
  • Close all valves and remove the gauges.
  • Double check for leaks and clean up your work area.
  • Record the quantity of refrigerant you have added to the system.
steps to charge 4
Steps to Charge 4
  • Watch the difference in gauge pressure as you are charging. The gauges can be misleading.
  • Low Charge:
    • Insufficient Cooling (low capacity)
    • Long Running Time
      • Continuous Running Time
      • High Operating Costs
    • Evaporator Icing Up
    • Superheat Higher than normal
      • Subcooling high
  • Low Charge, cont’d
    • Low wattage
      • Volts x Amps
    • Suction pressure low, discharge pressure low.
    • Compressor temperature higher than normal.
  • Overcharge
    • High suction pressure
    • High discharge pressure
    • Compressor sweating all over
      • Flooding - liquid in compressor
    • High wattage
      • Volts x Amps
  • Overcharge, cont’d:
    • High current draw
    • Low or no superheat
      • Flooded evaporator
      • Liquid filled evaporator