What must be done before shipping any used refrigerant in a cylinder?
Before shipping any used refrigerant cylinders, check that the cylinder meets DOT standards, complete the shipping paperwork including the number of cylinders of each refrigerant, and properly label the cylinder with the type and amount of refrigerant. Cylinders should be transported in an upright position.
What is the service procedure if the refrigerant in a recovery cylinder suspected to be contaminated?
If the refrigerant in a recovery cylinder is suspected to be contaminated, a pressure reading of the cylinder should be taken and compared to a pressure/temperature chart. Recovery cylinders are specifically designed to be refilled. Recovery cylinders have 2 ports, one liquid and one vapor.
What should be done to reduce refrigerant loss from a purge unit on a R 123 chiller?
How would you SAFELY reduce refrigerant loss from a purge-unit on a low pressure unit? 1) Leak test and repair the chiller. 2) Seal the purge-unit discharge. 3) Plumb the purge-unit discharge back into the low side.
When recovering refrigerant into a non pressurized container from a refrigerator with an inoperative compressor it is?
Which of the following refrigerants is most commonly used as a replacement for R-12 in new household refrigerators? When recovering refrigerant into a non-pressurized container from a refrigerator with an inoperative compressor: it is necessary to heat and strike the compressor with a rubber mallet.
Which of the following is an approved drop in service replacement for r22?
R-22 Replacement Alternatives R-410A is the best alternative option for air conditioning applications, while the best alternative for refrigeration applications are R-404A and R-507.
What is the maximum allowable Factory charge of refrigerant?
15 pounds
When should refrigerant be removed from the condenser outlet?
This preview shows page 46 – 49 out of 60 pages. Refrigerant should be removed from the condenser outlet if the condenser is below the receiver. In a building that has an air-cooled condenser on the roof and an evaporator on the first floor, recovery should begin from the liquid line entering the evaporator.
What gases can CFC refrigerants decompose into at high temperatures?
What acids can CFC and HCFC refrigerants decompose into at high temperatures (e.g. open flames, glowing metal surfaces, etc.)? hydrochloric and hydrofluric acids.
What is the first thing to do when a new system has been assembled?
When a new system has been assembled, the first thing to do is. evacuate the system. pressurize the system with an inert gas and leak check. pressurize the sytem with refrigerant to be used in the system.
When recovery is first started at what phase?
TYPE II
| Question | Answer |
|---|---|
| 6. When recovery is first started, at what phase is the refrigerant removed to save recovery time, | C. Liquid phase |
| 7. Where must you connect the hose in order to recover liquid refrigerant, | C. Liquid line |
Why does a pressure drop not necessarily indicate a refrigerant leak?
Why does a pressure drop not necessarily indicate a refrigerant leak? It may be indicating a temperature change. When calculating the effect of temperature change on a standing charge: Always use absolute pressure and temperature.
What is the first thing to do when a new system has been assembled built up and is ready for testing?
What is the first thing to do when a new system has been assembled (built up), and is ready for testing? Pressurize with an inert gas and leak check. You just studied 25 terms!
What is the proper method of charging a blended refrigerant?
Refrigerant charging with R-400 or R-500 series refrigerants Once liquid refrigerant is removed from the cylinder, the refrigerant can be charged into the system as a liquid or vapor as desired. Use gauge manifold or a throttling valve to flash the liquid to vapor if required.
How many different refrigerants should be recovered into the same cylinder?
How many different refrigerants may be recovered into the same cylinder when dealing with small systems? Only one.
How long must an HVAC servicing company keep records?
three years
Which refrigerants must be recovered before opening?
All CFCs and HCFCs must be recovered before opening a system for service or disposing of appliances. Cylinder & Appliance Disposal: Before disposing of any appliance containing a CFC or HCFC refrigerant, the refrigerant must be recovered.
Which refrigerant releases is considered a violation of the prohibition on venting?
Similarly, pure CFCs or HCFCs released from appliances will be presumed to be refrigerants, and their release will be considered a violation of the prohibition on venting.
How would you remove moisture from refrigerant in a system?
Moisture can be removed from a refrigeration system by applying a vacuum. POEs hold moisture more tightly than mineral oil. But in the case of R-134a, the refrigerant effectively competes with the ester lubricant in partitioning the water (i.e., the water moves from the lubricant to the refrigerant).
What happens if moisture is left in the system?
Moisture will cause acid to form in the system causing serious damage to the compressor and expansion valve parts. It also deteriorates the insulation of the motor windings in the compressor. In the more advanced stages, compressor motor burnout and repeated compressor motor burnout happens.
What happens to moisture in a vacuum?
In a vacuum chamber, the pressure can be extremely low. So low, in fact, that water can actually boil at room temperature. So, if you put some water in a high-vacuum chamber you will see it boil. (Then, with all that water vapor around, it won’t be a high vacuum anymore!)
Does vacuum remove moisture?
A vacuum pump removes air and moisture from the system before the system is damaged. The deeper and more complete the vacuum, the more moisture is removed, and the likelihood of system complications caused by unwanted water or other contaminants is reduced.
Is there humidity in a vacuum?
The presence of water vapor in vacuum systems is perhaps the most common of all problems that face the practitioners of vacuum technology. Water vapor, in the form of humidity, is found in all air.
Does vacuuming AC remove oil?
Pulling a vacuum will not remove the oil. Most of the time unless you replace your compressor or accumulator you should not need to add oil.
Is 1000 microns a good vacuum?
The following are guidelines for an acceptable standing level of vacuum. For systems containing mineral oil like R22 systems, a finishing vacuum of 500 microns with a decay holding below 1000 microns generally considered acceptable, whether we are talking a new installation or a system opened for service.
How many microns do I need for a good vacuum?
Finishing Vacuum (With a good pump 50-100 microns is easily achievable.) Isolate the vacuum rig with the core tools and allow the system to stand for 15 to 30 minutes. If the micron level does not rise above 500 microns the evacuation is complete.
How many microns is considered a deep vacuum?
500 microns
What is a perfect vacuum in microns?
In the micron vacuum scale, we start at 760,000 microns at sea level atmospheric pressure and work down towards a perfect vacuum of 0 microns or 0 hg. This is why a lower # in the micron vacuum scale equals a better / deeper vacuum, a higher number equals a worse / less deep vacuum.
What vapors does a deep vacuum pull out of the system?
The main reason for pulling a vacuum on a system is to rid it of unwanted gases, mainly air and water vapor. Air, being a noncondensable, will get trapped in the high side of a refrigeration system because the condenser’s liquid seal (subcooled liquid) at its bottom prevents the air’s passage.
How many microns does it take to evacuate an AC system?
What is considered a deep vacuum?
Deep vacuum— Refers to pulling a system down to as low as 20 microns. This method is accomplished by way of a two-stage vacuum pump. Detecting leaks — Once the system is evacuated, the vacuum pump is valved off. If the system pressure begins to rise according to the micron gauge, there is a leak.