hey all
I'm a service engineer new to the world of close control systems and currently completing my nvq level 3 with mainly vrv and split experience, and am looking for some more info on a liebert hiross down-flow unit, M47UA201VB02022FO,think its a hmp series? ,I've attempted the emmerson website & liebert hiross search but no joy and no O & M manuals on site,no history either..and boy did i look!
diagnosed a blocked filter drier today on a single compressor, r407c (20.6kg),air cooled system, all the obvious signs of a restriction i think, icing/frosting at the outlet back to expansion valve,temp drop across drier 7K!
error history(over past 12 months) was showing a few LP trips and further back HP trips.ran the system up SP 21c, AO 25.6c , suction pressure at comp inlet was 0.6bar , after the receiver it was rising above 17bar+ & after the drier before sight glass 3bar
comp pulled in ,drawing about 17amps running current(FLA 30A) and about 23(ish)Amps start up,then after about 3 minutes it tripped. LP fault came up on active alarm screen on the controller.no guess work there i suppose due to the LP.
then i asked the IT bloke a few things..:off topic:
so when i ran it up again to try take some more temps etc. just to satisfy my curiosity,it repeated the same sequence as before except the alarm now showing was for comp overload? happened another 2 times.
checked the windings and they were fine.
am i missing something obvious here? only managed to get basic level access i think (221)on the panel mounted control unit and couldn't get any sensor readings etc.
going back next week to do the dryer
if anyone could politely kick me in the right direction or towards a decent service manual or website would be mucho appreciated..
