Why are schematic diagrams often not true ladder diagrams? ...

[beccaep]

Why are schematic diagrams often not true ladder diagrams?
 
  What will be an ideal response?

Question 2

Explain a method used to determine the correct operating discharge pressure of a commercial refrigeration system.
 
  What will be an ideal response?

[CharlieArnold]

Answer to Question 1

Schematics commonly have some part of the diagram arranged to represent a part of the unit. For example, many schematics have the thermostat connections or unit terminal board connections drawn in the schematic in the same order and arrangement as in the unit.

Answer to Question 2

The method used is as follows:
Step 1  Measure the dry-bulb temperature of the air entering the condenser. (We will refer to this as the EAT  Entering Air Temperature).

Step 2  Measure the system's operating suction pressure.

Step 3  Using a Pressure/Temperature (P/T) chart, convert the suction pressure to its equivalent saturation temperature.

Step 4  Determine the system's application: low temperature, medium temperature, or high temperature. A low temperature system is one that operates at an evaporating temperature of 0F and below. A medium temperature system is one that operates at an evaporating temperature of between 0F and 25F. A high temperature system is one that operates at an evaporating temperature of between 25F and 45F.

Step 5  Using the chart below, determine the appropriate Temperature Rise (TR). The TR is the difference between the EAT and the condensing temperature of the refrigerant in the condenser.

Step 6  The Condensing Temperature

[beccaep]

Thanks

[CharlieArnold]

Welcome