concerned of liquid at suction line

[mangyan]

we just installed the condensing unit (climate control model number CDT0900L6).everything we did according to the specs, exept the initial charge. we did the leak test it seems okey and vacummed it to between 400 to 500 micron. we charged it liquid appproximately 48 lbs of r404a in discharge and suction line. after that we turn the crankcase heater on for the weekend, so that we are ready for initial run on monday.
my only concern is that the suction line might be in liquid form. i dont wanna damage the compressor. i need an advice. thank you.

[thegoodhumorman]

why in the world did you do that?
if you aren't able to run it and leave it pumped down at receiver why even add the gas- job run long and not want to pack it back to truck? crankcase heater will keep liquid out of crankcase unless really cold ambient, but liquid in suction side even in coil presents hazard. Next time just add five pounds to give it a positive pressure, charge it once it is running.

[matt8085]

How the hell did you get 48 lbs in without running it? Next time pump it down or wait to fully charge. When you go back there, front seat the suction service valve and then crack it open just a hair and monitor the amount of liquid you're getting back by amp draw of compressor and common sense. Good luck

[mangyan]

thank you matt and thegood for you advice. next time i will be aware of what i am doing.

[k-fridge]

Even better, recover all the charge from the low side before you start it up. How did you come up with the amount of charge? This is typically unknown due to varying line lengths. That's a lot of refrigerent unless its a big system. I echo the others that said if you're not gonna run it eight then just put a holding charge in to keep it under positive pressure and check for leaks.

[thegoodhumorman]

Originally posted by matt8085
How the hell did you get 48 lbs in without running it? Next time pump it down or wait to fully charge. When you go back there, front seat the suction service valve and then crack it open just a hair and monitor the amount of liquid you're getting back by amp draw of compressor and common sense. Good luck

follow matts advice- pinch suction down to about 1 to 3 lbs pressure at service port (running) and as you slowly pull down the evap coil side you will gradually open that suction port to keep it at the low inlet pressure aforementioned. Make sure you have front seated receiver so it is pumping down. Once done, open suction fully and crack receiver valve, perhaps half turn to allow it to get txv working, open another half turn after a minute etc. so you don't get any surprises.

[mangyan]

while regulating the pressure in suction line, do i need to consider the compressor amp draw ( from the leterature the LRA is 33.2 amps and a 9.0 hp compressor)? if yes what amp should i be?

[mangyan]

i'm sorry RLA = 33.2 and LRA = 215 with 9hp compressor

[thegoodhumorman]

honestly i don't hang ammeter on it- i try to run it as mentioned - just above vacuum until evaps are clear- you can be running below RLA and a slug of liquid hammers it anyway. It may take a bit longer but havent lost one yet- came close thanks to suction stops opening but so far so good... no I did lose one once but am stil over 99.9 percent

[Dowadudda]

just take your recovery pump and suck out from low side and transfer it to high side directly. It won't take more that a few minutes. Then start. Whats the big deal.

My question is like som of the others. How the heck did you get 50 lbs of liquid in there with out the unit running.

[mangyan]

we charge it while it is vacuum in liquid form since r404 is a blend. we empted two bottles of 24lbs. r404.

[mangyan]

we charged it in both side. more liquid is in the low side. the suction line is 1 3/8" and the discharge is 5/8".

[pecmsg]

You flooded the entire system with LIQUID. High side, Low side, Evap everything.

Pull the entire charge

[NedFlanders]

what the heck is going on? start it up.

Start with the suction valve closed to clear the comp.
Then as the comp clears , crack it slightly open.

Put your hand on the discharge line as you pump it out. It should be very warm ,basically untouchable. If it starts getting cold throttle the valve closed.

Keep the comp running as much as possible walking that line until the system is pumped down .