Why should you not start a hermetic compressor in a vacuum?

Why should you not start a hermetic compressor in a vacuum?

Never start the compressor while it is under deep vacuum. Always break a vacuum with a mini- mum 2 psig refrigerant charge before energizing the compressor. The compressor is cooled primarily by the flow of refrigerant. Running a system that is low on charge will reduce the life of the comperssor.

When evacuating a vapor compression system the vacuum pump should be capable of pulling a vacuum of?

Cards

Term Type II Technician	Definition Technicians maintaining, servicing, repairing or disposing of high pressure or very high‐pressure appliances.
Term When evacuating a vapor compression system, the vacuum pump should be capable of pulling… of vacuum.	Definition 500 microns (29.90” hg.)

What is hermetic compressor?

Hermetic compressor: A hermetic or sealed compressor is one in which both compressor and motor are confined in a single outer welded steel shell. Hermetic compressors are ideal for small refrigeration systems, where continuous maintenance (replenishing refrigerant and oil charge etc) cannot be ensured.

How is a hermetic compressor cooled?

One method is to use the returning suction vapor to cool the motor windings. This is used on all fully-hermetic compressors, as well as many semi-hermetic compressors. Another method used is to pass a sufficient amount of air across the body of the compressor.

What is deep vacuum in a refrigeration system?

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. Triple evacuation — A method of evacuation that initially pulls the vacuum down to between 1,000 and 2,000 microns.

What level of vacuum should be pulled when evacuating a vapor compression system to assure all moisture has been removed?

25 Cards in this Set

Which of the following should be replaced if a system is opened for servicing?	Filter drier
What level of vacuum should be pulled when evacuating a vapor compression system to assure all moisture has been removed?	500 microns

When did hermetic system first inspect?

TYPE II

Question	Answer
1. When first inspecting hermetic system known to be leaking, you should look for,	D. Traces of oil
2. Which part of a belt driven non-hermetic compressor is most likely to leak if the compressor is not been used for several months,	B. Rotating shaft seal.

Can a hermetic refrigeration compressor be damaged under a deep vacuum?

When under a deep vacuum the motor windings of a hermetic refrigeration compressor Could be damaged if energized Testing with soap bubbles is used To pinpoint refrigerant leaks Systems that useR-134a should be leak checked with Pressurized nitrogen

Why is recycling equipment using a hermetic compressor overheating?

Recycling or recovery equipment using hermetic compressor’s has the potential to overheat when drawing the vacuums because The motor relies on the flow of refrigerant through the compressor for Cooling The component directly following the evaporator of the refrigeration system is the Accumulator

How to recover liquid refrigerant from a vapor compression system?

In order to recover liquid refrigerant you must connect one hose to the systems Liquid line When evacuating a vapor compression system the vacuum pump should be capable of pulling a vacuum of 500 microns Liquid charging of an R-12refrigeration system with risk of freezing is begun with vapor from a vacuum level to a pressure of approximately

What is the refrigerant pressure of a R-12 air conditioner?

Terms in this set (67) The refrigerant pressure of an R-12 System while Idol at room temperature (72°F) is Approximately 74 psig Refrigeration and air-conditioning compressor heaters are used to Reduce the amount of refrigerant in the lubricating oil