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Thread: 4 ton split unit ac problem
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01-07-2012, 08:51 PM #1
4 ton split unit ac problem
hi every one
i got 4 ton split unit ac from general type heat and cool
with damaged compressor
so i replaced it with new one from some LRA and size
i checked compressor before installing so compressor worked properly
but when i started charging system i encountered this problem
if i charge the system with required amount of ***** by weight the compressor starting opening safety valves
but if charge system with little amount of ***** by weight the compressor and system work propely
i tried anothre types of ***** 22 and i made clean for the system and i changed the filter and expansion valves
i checked the electrical connection they are properly connected
can any one help me
Power consists not in being able to strike another but in being able to control oneself when anger arises
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01-07-2012, 09:13 PM #2
Well, you do have a head start...
You are online.
Do a quick search for air condition or refrigeration engineers in your neck of the woods and ask one of the local guys to sort it out for you.
Sorry, but there is a whole can of worms there that needs specialist knowledge to sort out.
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01-07-2012, 09:16 PM #3
Re: 4 ton split unit ac problem
ok
what is the cause of head start
what is the solution
can you advice mePower consists not in being able to strike another but in being able to control oneself when anger arises
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01-07-2012, 09:39 PM #4
Re: 4 ton split unit ac problem
the" head start" viking is referring to is the fact that you have access to knowledge- as long as you are able to provide us with more information like standing pressures,running pressures and compressor running currents- also superheat and subcooling values would be handy too.
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01-07-2012, 09:45 PM #5
Re: 4 ton split unit ac problem
hi install monkey
sorry for misunderstanding
ok i will check these info and answer you laterPower consists not in being able to strike another but in being able to control oneself when anger arises
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01-07-2012, 09:48 PM #6
Re: 4 ton split unit ac problem
but can you tell me why compressor couild open its safety valves
if there is no blockage or overcharged gas or compressor weaknessPower consists not in being able to strike another but in being able to control oneself when anger arises
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01-07-2012, 09:58 PM #7
Re: 4 ton split unit ac problem
4 ton- 14kw general- heat and cool- heatpump-(4 way valve)- do you have the model numbers of the old and new compressors, when you say you tested the newer compressor- you ran it on a bench to check pumping/operation
safety valve you are referring to the internal relief disc- to bypass discharge gas back into the compressor body.
changed drier and expansion valve - did you vac the system to under 2 torr, did you use nitrogen to purge whilst brazing and again to pressure test the system. - when the comp starts foes the internal relief valve open within 10seconds then its either a weak relief valve,,or overcharged due to non condensibles-air/moisture or the reversing valve is jammed
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01-07-2012, 10:07 PM #8
Re: 4 ton split unit ac problem
i think new compressor was from same type of the old one
i made a properly vacuum
i tested system for leakage
compressor suction and discharge were so goodPower consists not in being able to strike another but in being able to control oneself when anger arises
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01-07-2012, 10:46 PM #9
Re: 4 ton split unit ac problem
Maybe what killed the old compressor is trying to kill the new one?
Mostly found in Oxfordshire, UK :)
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02-07-2012, 08:16 PM #10
Re: 4 ton split unit ac problem
hi
i checked the split unit
4 way valve working properly
the problem start when charging reach 40 psi
discharge and suction connection both are not coldPower consists not in being able to strike another but in being able to control oneself when anger arises
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02-07-2012, 09:38 PM #11
Re: 4 ton split unit ac problem
at 39psi suction ,whats your discharge pressure?
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02-07-2012, 09:46 PM #12
Re: 4 ton split unit ac problem
i didnt check dis press
i know the problem start when suction connection start coolingPower consists not in being able to strike another but in being able to control oneself when anger arises
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02-07-2012, 10:46 PM #13
Re: 4 ton split unit ac problem
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03-07-2012, 08:17 PM #14
Re: 4 ton split unit ac problem
hi every one
thank you for helping me
i detected the cause of damaging compressor
the problem happened because of a device in indoor unit
the device is looks like expansion valve located in the discharge line in begining of indoor unit which is branching into the smaller pipes to the ervaporative coils.
since i didnt use netrogen to cleaning pipes
i only vacuumed it
after opening it by welding it was containing alot of slug and corrosion
so i changed it
thank you again
and sorry if made you tired with me
your replays helped me in solving problemPower consists not in being able to strike another but in being able to control oneself when anger arises
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03-07-2012, 09:44 PM #15
Re: 4 ton split unit ac problem
well done- we all learn on here!
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03-07-2012, 09:46 PM #16
Re: 4 ton split unit ac problem
thank you master for helping me
but i have question
if i have dirty system how i can clean it
by nitrogen or by whatPower consists not in being able to strike another but in being able to control oneself when anger arises
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03-07-2012, 10:06 PM #17
Re: 4 ton split unit ac problem
if the system is clogged- then degas from both sides of the system.cut out the drier- blow nitrogen down the suction line for a few minutes this will move any crap and exit the system at the open end where the drier was,and again add nitrogen into the discharge side again for a few minutes to clear crap again out where the drier was. then fit a new drier but slowly add nitrogen into the high side and leave the low side gauge connected to the system but disconnected from ur gauges- the nitrogen that passes through the system is verly low - not hissing , then vac and recharge with new gas- if the nitrogen is too much then youll struggle to braze the new drier in
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03-07-2012, 11:04 PM #18
Re: 4 ton split unit ac problem
thank you man you helped me
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08-07-2012, 08:12 PM #19
Re: 4 ton split unit ac problem
Use a BURNT out FILTER at the suction line before the compressor
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08-07-2012, 08:23 PM #20
Re: 4 ton split unit ac problem
what you mean by burnt out filter
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08-07-2012, 08:28 PM #21
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08-07-2012, 08:30 PM #22
Re: 4 ton split unit ac problem
thank you every one
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08-07-2012, 09:15 PM #23
Re: 4 ton split unit ac problem
suction burn out drier is fitted as close to the compressor on the suction line- then regular checks of the pressure drop accross the drier-note they are meant to be removed after a while-but no one usually removes em
every time u do a compressor change do an acid test on the oil- if acidic then fit the suction burn out drier- also acid away - is a neuraliser u can add to the new compressor prior to fitting
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09-07-2012, 12:12 AM #24
Re: 4 ton split unit ac problem
I usually use one or two size bigger than needed , to your case a 10 ton will be good.
So you do not have to worry about pressure drop.
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16-07-2012, 08:01 PM #25
Re: 4 ton split unit ac problem
thank you every one