ALASKAN ECU OVERVIEW
The Alaskan ECU Requires _ VAC, _ Phase, _ Hz to operate.
120/208, 3 Phase, 50/60Hz
What is the purpose of the drier in the refrigeration system?
Removes Acids, Impurities, and Moisture. (AIM)
According to EPA Section 608 how much refrigerant are we able to let out when working on refrigeration systems?
de-minimus amount
What is latent heat?
Change in State but no change in temperature.
True or False. The Primary Overheat Safety Switch (SOS1) manually resets.
False.
What type of refrigerant does the Alaskan ECU use and how much does it hold?
R-407C, 7 Lbs.
What happens to our refrigerants as it passes through our condenser?
It goes from high pressure high temperature vapor to high pressure high temperature liquid.
When pulling a vacuum in our refrigeration system, what does it mean if our manifold gauge is reading 0 PSIG?
Indication of leaking pump or hose connection or an AC system leak
What is superheat?
Heat that is added to a gas or vapor above it's boiling point.
What does CB2 protect in the Alaskan ECU?
Heater circuit
What PPE must we wear when we are working on the Alaskan ECU refrigeration system?
Thermal protective gloves
Goggles/Face Shield
Long sleeve shirt
Explain the characteristics of the refrigeration on the inlet and outlet side of the compressor.
Inlet: Low pressure low temperature vapor
Outlet: High pressure High temperature vapor
What are the differences between Azeotropic and Zeotropic refrigeration blends?
Azeotropic = Single Blend, cannot be separated through simple distillation.
Zeotropic = Ratio based, can be separated through simple distillation.
How does pressure affect boiling point?
An increase in pressure results in an increase in boiling point. - Direct Relationship
What is the purpose of the De-superheating valve (VE3)?
To prevent high discharge pressure.
If we need to have one of our refrigeration lines sent to metals tech for repair, why is it important that we remove all the traces of refrigerant?
Exposing R-407C to flame creates hydrogen fluoride, which is corrosive/toxic when combined with moisture and can damage components.
What does the metering device do in our flow chart?
Meters and restricts refrigerant to maintain 15-20 degrees superheat.
How do we determine the max safe weight of our refrigerant bottle?
TW + ((WC X SP).8) = max safe fill weight of the bottle.
What is the definition of a British Thermal Unit (BTU)?
The amount of heat required to raise one pound of water one degree Fahrenheit.
At what values do our condenser fans open and close?
Opens at 170 and 210
Closes at 250 and 320
Which equation best explains how the Alaskan ECU expansion valve operates to maintain the correct superheat setting leaving the evaporator coil?
Bulb Pressure (P1) = Spring Tension (P2) + Evaporator Pressure (P3)
What two components work together to create a pressure difference in our refrigeration system?
Compressor (MT3)
Metering Device (VE1)
What are the symptoms of a leak in our refrigeration system?
1. Compressor short cycling
2. Oily residue
3. hissing at the point of a leak
4. Warm evaporator coils
What are the three heat transfer methods? What are their definitions?
Conduction - Heat transferred through a solid object
Conduction - Heat transferred through a liquid or gas
Radiation - Heat transferred through rays or waves
How does VH1 work and between what parameters?
Increases system pressure by maintaining 45-48 PSI.