Piping Flashcards
What is the acceptable velocity for a horizontal suction or discharge line?
750-3000 ft/min
What is the acceptable velocity for a suction or discharge riser?
1500-3000 ft/min
What is the maximum velocity for a liquid line?
300 ft/min maximum (oil is miscible with liquid refrigerant)
What is the acceptable velocity for a condensate line?
120-150 ft/min
What is the typical sizing for the maximum line size?
Typically one size larger than the liquid line.
What type of flow does the maximum line size have?
Has sewer type flow, liquid down, vapor up.
What must the Hot Gas Defrost line maintain?
Sufficient refrigerant flow rate.
How is the velocity for the Hot Gas Defrost line determined?
At saturated conditions, resulting in a conservative line size.
How should the Hot Gas Defrost line be sized?
Properly sized to handle the calculated needed hot gas load, based on twice the evaporator flow rate.
What must the Hot Gas Defrost line prevent?
Condensed liquid refrigerant from backflow to the compressor while on defrost or shutdown.
What should be installed leading to the side of the inlet tee?
A check valve.
What is the recommended slope for piping?
½ inch per 10 feet in the direction of flow.
Where can temperature penalty data be found?
See Sec. 1, P. 8 for capacity vs pressure drop data.
What is the formula for temperature penalty?
Temp penalty = 2f x total pressure drop/pressure equivalent to 2f
How is total pressure drop calculated?
Total pressure drop = (pressure drop/100ft) x equivalent length
