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andyc425
11-07-2011, 06:42 PM
hi guys
currently working on a mitsi pury-p500 connected to 13 indoor fan coils mix of splits and cassetes and im doing the full works pressure test -vac- charge, and as i am not familiar with this system need some advice as to wether power needs to be kept on to allow valves to stay open on bc box and lev etc . i am told that all indoor units power needs to be isolated but then i am told that disconnecting the transmission wires on the outdoor unit will do the job with the condenser left on is this normal practice ? and if so is this sort of procedure just done on mitsi's? any feedback appreciated i dont want to mess this up with a simple but tedious mistake.

cheers .

martinw58
11-07-2011, 09:06 PM
do not put power on untill you have pressure tested and vaced unit come with eevs open when you power up thay wiil close

stufus
11-07-2011, 09:10 PM
On the Mitsu stuff it makes no odds power on or off.But if you're leaving the power on it's best to pull the transmission plug off the outdoor board so some numpty doesn't come along and try to start it.The Mitsu gear has tiny holes in most of the valve seats to allow system equalisation .Other manufacturers stuff differs Daikin have a test setting for this and Sanyo have a set of pins on the outdoor board that when shorted out open all the valves.
Its straight forward with the Mitsi.
Cheers
Stu

andyc425
11-07-2011, 10:27 PM
cheers guys iv left the outdoor unit on and transmission wire back in but sealed off all controllers indoor and let staff no. if by some chance they do try starting it will just fault on LP anyway.just another quick one i will be charging 38 kgs once i pulled the vac and i usually get as much in high side as possible as liquid, then flash into low side or use kwik-tool but unfortunatly dont have one anymore and flashing will take some time ,do you guess use the flashing technique often on this scale and if so how many grams do you flash at a time ?

cheers

stufus
12-07-2011, 08:48 PM
The 500 has a big accumulater so can take a good slug into the suction pipe so no major worries there. The problem with 410a is over coming the runnig pressures with the cylinder pressure. A cylinder heater is handy or load as much as you can into the system then use a recovery unit to put the rest in. Allow it to stand for a while then switch it on. Job done.
Cheers
Stu