I have a client with a system shutdown on high head pressure when trying to start his AC system at 130 DegF ambient at the condenser and the evaporator. If the pressure switch is jumpered out, the system will run and drop to normal operation pressures after 20-30 seconds. Any recommendations for...
When working out the sub-cooled liquid density, do you use the sub-cooled temperature or the saturated pressure liquid density. For example: R134a at 300psig has SCT of 160ºF and liquid density of 61.74 lb./ft^3. However, it is sub-cooled 10ºF. Do I then look up the liquid density at 150º which...
I have heard of a general rule of thumb for R134a refrigerant that 1ºF of cooling is lost for 2psig pressure drop on high side. If the pressure drops on the discharge side, the SCT decreases and thus the we would be closer to the SCT for the discharge pressure. Is this not an advantage to...
What is the result of excessive pressure drop in the suction line? I typically have seen suction line design for 1-2 psig drop.
We have a bus AC system measuring 25-35 psig drop from evap out to compressor suction. The line sizes are obviously too small and that is being changed. However, I...
We are looking at designing chiller packages using R410a refrigerant. The problem I have is selecting the tube size for R410a pressures. Using the ASME B31.5-2006 only allows me to go up to 7/8" copper lines with R410a working pressures (Type K, annealed copper). Is there another type of copper...
