Compressor Pack Control?

[monkey spanners]

How are the compressors controlled? I have a couple of packs i want to pump down as the systems are being decommissioned.

Looked like about seven Dorin comps on each in a light grey steel enclosure, with the condensers behind but walled off from the comp compartment.

All the cases have solenoids so i wondered if its just run off suction pressure and i can either liven them up or bung a magnet on them...

Think it used to be a somerfields.

Cheers Jon

[simon@parker]

find yr main liquid line close it down it should pump itself down then on comp LP switches depends who makes it wether theres an override to run comps you will need to turn the cabs on and get them to run for bit while yr pumping down on a running system should take bout 30 min on a system thats been standing and off might take couple of hrs you can then close reciever down and reclaim condensers to it if theres room easy days work lol

[Mark]

Hi

In a nutshell the Pack Control will run the compressor/s and or the condenser fan/s in order to achieve a target Suction & Discharge set point.

Depends on the configuration of both the primary pack controller and how the back up is wired and set up.

Kind Regards

Mark

[Tayters]

Hi Jon,

Well I'm no pack guru (as I may well prove) but I'd turn it all on, close liquid outlet from reciever and oil feed oulet from oil sep then monitor high and low side pressures.
Not sure what kind of pack controller you'd have there but either way when it reaches its setpoint time to wedge a couple of contactors in to suck back the rest. Seems best with the big systems to suck back until 0psig then wait for suction pressure to settle again before restarting the compressors. Then just a case of repeating that last bit until suction stays down.

If the system has been running then by the third or fourth cycle should see you done.

I watch the high gauge just incase the reciever/condensers don't have enough room to store all the charge and the old girl starts to groan around some corroded pipework!

That does leave the question of what to do with the oil feed lines. If there is some kind of oil management system there, with a line full of liquid (oil) then there may be the possiblity of trapping it. May need to energise solenoids as required to relieve the pipe of it's load (oo-er missus) seeing as the plant will be shutdown for a while.

CPC controllers have a row of dip switches which you can move up to force on each individual compressor. This comes in handy for pumping down. Not seen this on other controllers so in with the contactor wedging. Somerfields were big on JTL I seem to recall.

The cases will need turning on unless you've got a healthy stash of magnets The more the merrier as it'll pump down quicker. If it's a hot gas defrost system then no cases on defrost or the hot gas puts a spanner in the works.

Hope that help,

Cheers,
Andy.

[monkey spanners]

Thanks for the replies

Think it would have taken the old ecobuddy reco machine a month to suck it out as a vapour!

Jon

[simon@parker]

somerfields were big into elm systems so if you got an elm hand unit you can set suction set point to 0psi if you have individual isolators on the compressors you are only going to need 3 or 4 to run turn yr cabinets on slowly 2 or 3 at a time 20 mins minimum if it all off or you will pop whole thing out on head if they big compressors you will need to warm cranks first at least 2 hrs so you dont ship oil theres usually always a manual overide switch in case controller fails this will run all comps on there pressure switch settings and condenser fans at full tilt if you isolate a few condenser fans and get reciever nice and warm you can shoot alot of liquid straight into reclaim bottles make life easy for yrself lol

[monkey spanners]

Thanks again, turned all the cases on after i had shut the recievers and they pumped down to around 1.5bar, then out with the magic contactor manual operation device and we got down to 0.

Turns out there were three seperate circuits, two high temp and one low. Got about 200kg R404A out in total.

It did have an elm controller, which i had a play with, the compressors were arctic circle/gelphamatics which i've never heard of before

Found some melted plastic in the drier core which i think must have been a pipe cap left in during brazing. (yeah i got bored and started seeing how things worked....)

All i need now is for them to pay for it all

Cheers Jon

[Tayters]

When are you back to take the pipes out? ;-)

[monkey spanners]

When are you back to take the pipes out? ;-)

Was going to chop a few pipes out as when i started the shop fitters said they didn't want any of it but by the end of the day they had the disk cutters going chopping all the coils out of the cases etc.

I got a couple of the two deck stock trolleys and i found a whole pound on the floor! (am easily pleased LOL)

Jon

[simon@parker]

would have been a kwik save with artic circle units lol how sad am i knowing that and the gelphemetics aint to bad a unit till they break lol if you stip comps off pack someone will buy them from you as well cant beat a supermarket rip out them were the days van loaded down with evap coils lol ahhhhhhhhhhhhhhh beer money