Commercial Air Conditioner
Model: heat pump, 10SEER UNITS
9
3.SAFETY PRECAUTIONS
CAUTION
:
To ensure proper installation and operation, completely read all instructions prior to
attempting to assemble ,install ,operate, maintain or repair the product.
WARNING:THE MANUFACTURER’S WARRANTY DOES NOT COVER ANY DAMAGE OR DEFECT
TO THE AIR CONDITIONER CAUSED BY THE ATTACHMENT OR USE OF ANY
COMPONENTS,ACCESSORIES OR DEVICES(OTHER THAN THOSE AUTHORIZED BY THE
MANUFACTURER)INTO,ONTO OR IN CONJUNCTION WITH THE HEAT PUMP.BE AWARE THAT
THE USE OF UNAUTHORIZED COMPONENTS,ACCESSORIES OR DEVICES MAY ENDANGER
LIFE AND PROPERTY.THE MANUFACTURER DISCLAIMS ANY RESPONSIBILITY FOR SUCH LOSS
OR INJURY RESULTING FROM THE USE OF SUCH UNAUTHORIZED
COMPONENTS,ACCESSORIES OR DEVICES.
●
Always use good industry-recognized service practices in the maintenance, adjustment and repair of
the products covered in this manual to protect the technician and the customer.
●
Always wear safety glasses when handling refrigerant and brazing materials.
●
Follow the manufacturer’s instructions when making repairs and installing replacement parts and
assemblies.
●
Use only authorized parts to ensure that the equipment operates at the efficiency and useful life that
the manufacturer built into the product.
4.SYSTEM COMPONENTS
AND FUNCTIONS
This section describes the various air conditioning components, their purpose and operation. This
section is only a guide and does not consider all components that could be found on an air conditioner in
the field.
COMPRESSORS
The heart of any refrigerant system is the compressor .It is a pump causing refrigerant to flow. There are
several different types of compressors ,but all use electricity to turn an electric motor to drive a pump.
Air conditioners use two types of compressors. The first is the enhanced reciprocating compressor .It
operates with an offset crankshaft and pistons, and resembles an internal combustion engine. The
driving force is supplied by an electric motor turning the crankshaft and forcing the pistons into the
cylinders where valves control the flow of refrigerant. The valves provide a seal between high and low
pressure sides of the system. If the valves are damaged ,the compressor’s reliability, efficiency and
effectiveness are reduced or eliminated
Reciprocating type compressor
Scroll type compressor
Fig.4-1
Generally, liquid refrigerant is suspected if valve damage occurs. Some compressors can tolerate the
presence of small amounts of liquid refrigerant in the returning gas, but none are designed to withstand it
continually. Returning refrigerant cools the compressor motor. Surrounding the motor with low pressure
gas gives it the name of “low-side” shell compressor.
The scroll compressor used a helix (similar in shape to a snail shell)
to move refrigerant. When placed
within a similar stationary helix, the moving helix rotates so that the space between the two constantly
decreases as the gas moves toward the center of the Scrolls. The returning refrigerant gas first cools the
motor, then flows into the suction intake of the compressor scroll. The discharge gas leaves from the
center of the helix and exits the compressor. The lower part of the shell should be cool to the touch.
All current single phase units use two types of compressors .In construction, the two compressors are
quite different. In function they are identical. Scroll units do not need start components or crankcase
heaters. The reciprocating compressor may need both. Both types benefit from using a time-delay. This
