Hi Guys.
I am slightly confused as to what actual system Lambo has.
Only on the systems I am used to looking at a pumped system has Coolers which operate on a flooded principle.
Which when stat is satisfied the Liquid line Solenoid valve shuts the fans stay running as does the WSSV.

The cooler is slowly emptied by the wet return action / heat load on cooler!

Once set point rises the liquid line solenoid valve opens and a SMOOTH transfer of "Wet Vapour / liquid is maintained at all times.

Resulting in a stable liquid level / Suction Temperature control of the plant within the surge drum.
On Hot gas defrost it is indeed closed and a regulated bypass is then used to bleed the refrigerant / Gas back via the wet suction line.
Obviously It depends what system we are all talking about, but I would not expect the suction Valve to shut
along with the Liquid line valve on a normal pumped Ammonia System.

What do you think?
Grizzly