gas noise from pipe work

[bashdown]

i have just installed a vrv 3 and all units call ok but when i put 1 or more units on heating i get a very loud gas noise round all the pipe work have checked all pipe work out and all is ok . when i put all units on heating i dont get this noise . the nice man is comming tomorow from daikin but eny 1 have eny idears

[brunstar]

i think you may have crossed pipes buddy, probably discharge and suction cos when the system is in full cooling the discharge becomes a suction line.

[icecube51]

yep, check the connections on the "multiboxes" or whatever there cold.
its no shame when it happens,but you do it only once(LOL)

Ice