Pressure drop

[powell]

I have a walk-in freezer with duel evaporators. There is approximately 90 feet of suction line back to the condensing unit. The suction line has solenoid valves, filter and an accumulator. Taking pressure reading at the compressor how do I find the pressure drop for superheat calculations?

There's really no magic way. Installing an access fitting at the evap outlet is the only accurate procedure.

Heatcraft's piping chart list the pressure drop for copper fittings and pipe.

Here's the link to this manual. http://www.hvacrinfo.com/loadcalcs.htm

Just curious, why is there a solenoid valve in the suction line?

To find the pressure drop for the solenoid you will need to get the part number and brand of the valve and look in the manufacturers catalog. Same rule applies for the accumulator. Unless the suction filter has an outlet access fitting, it's a guess.