I would like to ask for advice regarding drain and test connection.
According to point 188.8.131.52.4 and figure A.184.108.40.206(b), test connection should be above waterflow switch, does the drain also like in figure A.220.127.116.11(b)? Is backward flow when draining the sprinkler section, could damage waterflow switch?
I would like to ask for advice, is arrangement as below is good, or should I move drain valve above waterflow switch? Based on the drawings in NFPA 13:2016 below is incorrect, am I right?
I will be very grateful for help and advice.
Thank you in advance,