Training on 2P-Air

ConditionersBy: Bisrat EngidaworkAir condition Engineer

Outline

Thermodynamics Introduction Basic Refrigeration Cycle Fundamental of Air Conditioners Hisense 2P air conditioners operation Maintenance & Trouble shooting Tools for Refrigeration

Introduction

Why do we need Air Conditioner?

To control the temperature of a room To control the humidity of a room To enable the normal circulation of air through

out the room To control the quality of air in the room

Thermodynamics Introduction The Gas Law PV = nRT Where , n represents the number of moles of a gas and the constant

R is a universal constant and has a value of 8.31447 J/mol·K.

Temperature- Measure of the degree or intensity of heat of the environment or atmosphere.

(units°C-centigrade, ° F- farahanit, Kelvin)

Pressure- the force per unit area exerted by a liquid or gas on a body or surface, with the force acting at right angles to the surface uniformly in all directions.

Units(Psi,bar,kg/cm2 )

Thermodynamics cont’d

Thermodynamics Introduction

Humidity - Ratio of amount of water vapor present in air to greatest amount possible at same temperature

Dew point -Temperature at which vapor begins to condense and deposit as liquid

Evaporation- Term applied to the changing of a liquid to a vapor

Condensation- Liquid or droplets which form when a gas or vapor is cooled below its dew point

Thermodynamics processes

Sensible Heating/cooling- A term used in heating and cooling to indicate any portion of heat which changes only the temperature of the substances involved .

Heat that changes the temperature of a substance when added or removed from it.

Latent Heat -Heat characterized by a change of state of the substance concerned, for a given pressure and always at a constant temperature for a pure substance i.e. heat of vaporization.

Heat that does not affect the temperature of a substance but changes the state when added or removed from it.

Dehumidification-Removing of water vapor from the environment or atmosphere

Humidification - Adding of water vapor to the environment or atmosphere

Basic Refrigeration Cycle

In mechanical refrigeration, constant cooling is achieved by the circulation of a refrigerant in a closed system, in which it evaporates to a gas and then condenses back again to a liquid in a continuous cycle.

Compression systems employ four elements in the refrigeration cycle: Compressor, Condenser, Expansion valve, and Evaporator.

Refrigerants

Refrigerants known as CFC12 (R12) and HCFC22(R22)Hydro fluorocarbons R410, R407C

Refrigerants known as CFC12 (R12) and HCFC22(R22) are stable, In the upper atmosphere the refrigerant molecules breakdown and release chlorine, which destroys the ozone layer.

Basic Refrigeration Cycle

Low Pressure Switch低压开

关

High Pressure Switch高压开

关

Compressor压缩机

Sight Glass视液镜

Evaporator /Cooling Coil蒸发冷却盘管

Condenser Coil冷凝盘管

Solenoid Valve电磁阀

Filter Drier干燥过滤器

Hand Valve手阀HS

Service Valve检修阀

ThermostaticExpansion Valve热力膨胀阀

Capillary Tube毛细管

Suction Line Insulation Tube吸气保温

Suction Line吸气

Discharge Line排气

Liquid Line液态

High PressureGas高压气体

High PressureLiquid高压液体

Low PressureLiquid低压液体

Low PressureGas低压气体

Refrigeration Cycle

1. The Compressor draws the Low Pressure Gas from the Evaporator and compresses it to a High Pressure Gas (high temperature) and forces it into the Condenser

2. The Condenser has a draught of air flowing over it which absorbs heat from the refrigerant as it condenses to a liquid

3. Liquid refrigerant from the Liquid Line is forced by the high pressure gas in the Condenser, along the Liquid Line until it reaches the Thermostatic Expansion Valve

Cont’d

4. The Thermostatic Expansion Valve throttles the High Pressure Liquid as it passes through a small orifice to the Evaporator where at this end it exists as a Low Pressure Liquid

5. The Thermostatic Expansion Valve varies the amount of refrigerant entering the Evaporator in accordance with the thermal load

6. This Low Pressure Liquid absorbs heat from the adjacent surrounds, through the Evaporator and changes to a gas and expands

Hisense 2P Air conditioners

Cont’d Air Intake Grille: Air from the room is drawn and filtered

by filter.

Air outlet: Conditioned air is blown out of the appliance through this section.

Remote controller: It controls ON/OFF, operation mode selection, temperature, fan speed, timer setting and air flow direction.

Outdoor unit: It consists of compressor, fan , heat exchanger and electric parts.

Hisense Refrigerant flow diagram

Safety Precautions When abnormal phenomenon occurs during the

operation of the air conditioner, turn off the appliance first and then pullout power plug or cut off the power supply.

Before opening the appliance to check the electric parts and lines, please cut off the power supply of the air conditioner.

During the maintenance work, fingers, gloves and clothes should be far away from the moving parts such as rotating fan.

Never leave foreign articles such as metal pieces and the ends of thread inside the appliance.

Cont’d Never put fingers or foreign bodies into the air inlet and outlet of

the indoor unit and out door unit, which results in malfunction to the appliance or injury to the personnel.

Take care for frost bites when measuring pressure of a gas or charging refrigerants to the AC, connecting the pressure hose as fast as possible.

Introduction to Remoter Display

Cont’d

Cont’d

Cont’d

Air conditioner operation Temperature setting ---- 22°C-30°C, optimum temp 25°C

FAN Speed - AUTO Flap Direction- AUTO (not blocking the out air flow) Refrigerant working pressure R22

Working pressure 3-5Bar,optimum pressure 4bar. R410

Working pressure 5-7bar, optimum pressure 6 bar

Gas charging to Air conditioner

Using Vacuum Pump When change the compressor After retightening the gas pipe checked for leakage After new installation;

Out door electrical wiring

Indoor electrical wiring

Maintenance of air conditioners Preventive Maintenance Anti mold filter cleaning at least once every month

Cleaning the out door unit from any blockage and plants around it Clean the water pipe line and check for any blockage with dirty Check all the pipes and pipe connection for any refrigerant leakage. Check the out door fan working properly.

AC Trouble ShootingTrouble Possible Cause Possible Solution

Air Condition does not run

1. Power failure2. Breaker tripped3. Line voltage is too low4. Operation state is wrongly set by remote controller

5. Batteries in the remote controller

1. Restore power2. Check AC breaker3. Check mains AC voltage4. Set the correct mode of

operation5. Replace new batteries

Ice on the low pressure line of the out door line

1. A blocked air flow (by dirt) 2. A blower fan which has lost its ability to move air 3.Improper refrigerant charge 4. Remote control setting problem 5. A malfunctioning auto-defrost control 6. A malfunctioning refrigerant metering device

1. Clean the filters properly2. Check the Fan working properly3. Check the refrigerant pressure4. Set the temperature according to the room condition5.Check the auto defrost is in the right position and working6. Check the metering is working properly and any leakage

Cont’d

Ice on the Out door Pipe and inside the indoor evaporator coil

AC Trouble ShootingTrouble Possible Cause Possible Solution

Ice on the high pressure line out door pipe

1. Low refrigerant2. Indoor Fan not working

1. Check for any leakage and Charge refrigerant to the AC

2. Check whether the indoor Fan working properly

Frost or Ice Forms on indoor evaporator Coil

1. Dirty blocked evaporator coils

2. Refrigerant loss / too much refrigerant

3. Wrong temperature setting4. Non-functioning blower

fan assembly5. A malfunctioning auto-

defrost control

1.Clean the filter and evaporator2. Check for any leakage on the

pipe connection and in indoor and out door unit. Check the pressure and charge the right refrigerant

3.Set the temperature according to the room condition

4. Check the indoor fan working properly.

5. Check the auto defrost is in the right position and working

Cont’dTrouble Possible Cause Possible Solution

Water dropping from the indoor unit

Dirty blocked the water line Carefully clean the water line

Compressor runs but soon stops frequently

1. Obstruction in front of the out door unit

2. Compressor over heated3. Mains voltage too low

1. Remove any obstruction2. Check whether enough/excess refrigerant

on the AC3. Cool down the compressor with water4. Set the setting to the right temperature5.Check the mains voltage

Out door Fan not work

1. Mains voltage too low2. Fan Capacitor not working

properly

1. Check the voltage2. Check the fan capacitor and replace it

Cont’dThe indoor unit fan does not run

1. Ice blocked the fan2.Wrong setting in the remote control unit3. Fan motor damaged

1. Remove the ice by turning off the AC.2.Set the correct state in the remote control3. Replace the fan motor with good one

Poor cooling performance

1.Dirty or clogged air filter2.Too many equipments in the room3.Doors and Windows are open4.Obstacle near air intake or any air discharge5.Thermostate is set too high6.Refrigerant loss/too much

1. Clean the air filter 2. Add new air conditioner3. Close them so that the cold air not go out4. Remove the obstacle to ensure good air flow5. Set the temperature lower6. Check the refrigerant pressure & charge gas

Maintenance Notes

When the refrigerant pressure is low, find the reason for refrigerant loss and find the leakage place and solve it

Always check the indoor unit and pipe connection places, and the out door valve not leaking.

Be sure the connection of pipes are firm after tightening

Make sure any water, dirty or air not entered to the air conditioner system, use the right quality refrigerant for each air conditioner which results in blockage of the pipe.

Cont’d

To replace damaged compressor Power off the air conditioner Remove the gas from the system Remove the electrical connection to the compressor Disassemble the out door cover so that you can take out

the compressor easily Disconnect the suction & delivery pipe by glowing it with

welding torch and take out the pipe slowly. Replace the new compressor to the right place and then

weld it to the pipes

Tools for air conditioner maintenance

Thank you!!!!