Hot Gas Defrosting System Design

[wzal]

Hi, I am designing the defrosting system for a box @ -18 C. I installed one solenoid valve on liquid line and another one on hot gas line. Do I need to put one valve (check valve or solenoid valve) on discharge line between compressor and condenser inlet? I checked a few books and found it was not on the diagram. But when I did some test with only two valves I installed, it seems to me there was some liquid running from condenser to the hot gas line during defrosting cycle.
Any input will be appreciated.

Cheers,

 

[imok2]

Your take off should be on top of discharge line and gas should be very close to the compressor if its too far you may be desuperheating too much For a full explanation go here:

http://www.sporlan.com/90-40.pdf