Pressure drop

[akcwby]

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?

[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.

[akcwby]

Im sorry, there is no solenoid in the suction line. I planned on putting access fittings in next time it goes down. That is a great link thank you.

[Brian_UK]

If you have an externally equalized TXV/TEV you may be able to put an access point at the valve balance line connector.

[Magoo]

Pump down system and install a schrader access port at the point in system that the TX valve buld is fitted. Gauge at that point versus a gauge at compressor will tell all.
Every bend ,fitting and pipe size and length of pipe will add superheat to compressor performance, and de-grade system performance accordingly. Try and keep max loses or super heating loses to max +5.0 ' C. Vertical head losses can be a killer with liquid lines loses producing flash gas liquid feeding TXV. System performance reduced.

magoo