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Shatner
28-03-2010, 02:01 PM
I recently completed an installation of a Liebert unit for a data room. This system consisted of a roof mounted condenser and the air handler section, w/compressor one floor below. The Liebert installation manual requires an inverted trap on both the discharge and the liquid line. I have read in other souces that the trap in the liquid line is not necessary. My understanding is that it prevents liquid from siphoning out of the condenser, and that it prevents liquid from migrating back to the condenser during the off cycle. It would seem to kepp any aditional weight from liquid refrigerant off the L.L. solenoid or the TXV for units without a solenoid. Any input would be appreciated
nike123
28-03-2010, 02:49 PM
My understanding is that it prevents liquid from siphoning out of the condenser, and that it prevents liquid from migrating back to the condenser during the off cycle.

Do as said in instalation manual.
If there is no solenoid valve at liquid line it is possible that all liquid migrate from condenser to evaporator during off period (TXV is never 100% closed) and when compressor start, high risk of liquid in compressor is possible.
Shatner
30-03-2010, 12:48 AM
I definately followed the installation manual. I just want to make sure I have a correct understanding of why this is required.
Shatner
31-03-2010, 01:08 AM
I tried to attach the installation manual, for some reason I couldn't make that happen. It does require inverted traps. It looks like they replaced the L.L.trap in your drawing with a check valve? I don't mean to sound like a dope, I'm fairly new to the trade. I've been an electrician for 23 years. I'm what you might call a re-tread!
nike123
31-03-2010, 09:03 AM
I tried to attach the installation manual, for some reason I couldn't make that happen. It does require inverted traps. It looks like they replaced the L.L.trap in your drawing with a check valve? I don't mean to sound like a dope, I'm fairly new to the trade. I've been an electrician for 23 years. I'm what you might call a re-tread!

Inverted trap or check valve, they have same function to prevent liquid refrigerant to migrate in off period.
Shatner
31-03-2010, 04:53 PM
Thanks very much