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Thread: Ice building up
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12-08-2011, 11:17 PM #1
Ice building up
I have problems with air condition unit Denco Model U5AG. Ice is building up on lower part of evaporator and a lot of ice building up around expansion valve and suction stop valve. Sight glass is clear with no bubbles. I tryed to fill 300 gram with R22 but it is not getting better.
I have some measurings before and after filling.
Before:
Evaporator pressure 1,8 bar
Condensator pressure 11 bar
Suction temp -14 degrees
Pressure temp 56 degrees.
After filling 300 gram and 30 minutes running a lot of Ice had again build up and readings was:
Evaporator pressure 1.1 bar
Condensator pressure 10 bar
Suction temp -7 degrees (use IR temp reading so maby not correct)
Pressure temp 56 degrees
Differential pressure before and after dry-filter is 1 bar.
What can be wrong here?
Please help!
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12-08-2011, 11:57 PM #2
Re: Ice building up
Hi Karlsen
sounds like blocked drier (dry-filter) - if I understand your post correctly
I have ir thermometer - supposed to be good (fluke) but it's always reading wrong
ok for rough guide - not trouble shootingIf the World did not Suck, We would all fall off !
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13-08-2011, 12:40 AM #3
Re: Ice building up
Thank you Chillerman! Will a blocked drier result in ICE on expansion valve, suction stop valve and evaporator? If so, I will change out filter. Thanks..
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13-08-2011, 12:57 AM #4
Re: Ice building up
if the drier is blocked you will not get a clear feed of liquid between drier and txv
you then got frosting on valve and first section of evaporator
easy check - even though ir is not accurate - you can check for temperature drop
either side of drier - on pipework
hard for me to say for definate whats going on as
pressures & temperatures do not add up to me - probaly IR thermometerIf the World did not Suck, We would all fall off !
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13-08-2011, 03:18 AM #5
Re: Ice building up
Hmm.. Just checked temp before and after filter. Temp before filer 21,8 degrees and 21,6 degrees after filter. Diff temp.0,2 degrees. Maybe not drier than?.. A lot of ice on txv valve, first section of evaporator and a lot on suction stop valve on compressor.
But this pressure readings sounds normal doesent it? (R22 on the system)
Evaporator pressure 1.1 bar
Condensator pressure 10 bar
It is a air condition unit. Room temp 28 degrees. Air outlet of evaporator = 15degrees. That is ok I think. The problems is due to Frost/Ice occuring after some hours running. This block the air passing evaporator. Leads to poor cooling of room.
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13-08-2011, 04:21 AM #6
Re: Ice building up
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13-08-2011, 04:33 AM #7
Re: Ice building up
Sorry Karlsen
Gary is on the ball
I missunderstood "suction stop valve"
If your icing right back to the compressor, your not putting heat into the evaporator = low superheat
And as Gary said - air flow problem
everything going wrong tonight, have been doing three things at once
putting links on here for manuals & now google have locked me outIf the World did not Suck, We would all fall off !
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13-08-2011, 05:35 AM #8
Re: Ice building up
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13-08-2011, 05:57 AM #9
Re: Ice building up
nice one mate
Put your theory to the test the other day - worked well thankyou
Got me out of trouble when I was looking at counter
only had a shreider fitting on suction + had to decant + recharge
Got all my probes set up as you advised
charged to 1 degree C subcooling 8 degree superheat, it ran perfect
cheers
you might like the links on here mate
http://www.refrigeration-engineer.co...-york-pac-workIf the World did not Suck, We would all fall off !
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16-08-2011, 07:36 AM #10
Re: Ice building up
I understand, but my last readings after adding 300gram R22 are:
Suction pressure 1,1 bar = -26 degrees
Suction temperatur measured with IR-Termometer = -14 degrees.
This is 12 degrees superheat isn`t it?
I am thankful for more input to continue troubleshoting. This unit make a lot of ICE... I dont need ICE
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16-08-2011, 08:06 AM #11
Re: Ice building up
Ah, suction should be around zero C, 400 divided by 6.92,...Eh, PSi of 57.8... divided by 14.7 is now..3.9 bar on R22. So how does one get ice on suction line with such a low suction pressure?? Did you follow Gary's advice in post above?
To the optimist, the glass is half full. To the pessimist, the glass is half empty.
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16-08-2011, 09:36 AM #12
Re: Ice building up
Ok so Suction pressure is far to low.. I think air flow seems ok, but I can do a survey of kondition of the fan. Evaporator is clean. Other things than low air flow that result in that low suction pressure? Something wrong with TXV maybe?
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16-08-2011, 12:34 PM #13
Re: Ice building up
Is the compressor manufacturer or a smart guy has replaced by a biger one??
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16-08-2011, 02:48 PM #14
Re: Ice building up
Last edited by Gary; 16-08-2011 at 03:14 PM.
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16-08-2011, 03:30 PM #15
Re: Ice building up
The difference between entering air and leaving air is the coil's delta-T or dT. Contrary to popular opinion, the pressures are not the most important measurements on the system. Delta-T overrides everything. Unless/until the system has proper airflow through both coils, nothing else matters and all other measurements are meaningless. Always check the airflow first.
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16-08-2011, 05:12 PM #16
Re: Ice building up
Manufacturer compressor
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16-08-2011, 05:13 PM #17
Re: Ice building up
Thanks, will do more research on air flow than..
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19-08-2011, 07:52 AM #18
Re: Ice building up
i bielive you have lower temperature outside of the room so you can fix on the condenser fan a speed control to keep the condensator pressure min 16bar
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19-08-2011, 09:10 AM #19
Re: Ice building up
This should be fairly easy to solve. Perhaps take another engineer for assistance..
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19-08-2011, 07:40 PM #20
Re: Ice building up
Mr, K N.
IF POSSIBLE CHECK PRESSURE ON BOTH SIDE OF THE EVO IN & OUT IT SHOULD BE SAME!
rgds.
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19-08-2011, 07:53 PM #21
Re: Ice building up
If the World did not Suck, We would all fall off !
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19-08-2011, 08:04 PM #22
Re: Ice building up
ok guys sorry to say it but it looks like were all pi**ing in the wind,if u have a suction pressure of 1 bar then check belts and filters if theyre ok ring denco!
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19-08-2011, 08:11 PM #23
Re: Ice building up
forgot to mention 1 bar suction 10 bar discharge on r22!!!! its not a vector unit,pressure test it to 28 bar fix leak and run it at 58suction 200 head (4 bar and 16bar) fit a sight glass near the expansion valve to ensure full of liq
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19-08-2011, 08:11 PM #24
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19-08-2011, 08:12 PM #25
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19-08-2011, 08:13 PM #26
Re: Ice building up
whilst posting, my cake muncher is watching east enders -ur the ian beale of RE haha
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19-08-2011, 08:21 PM #27
Re: Ice building up
You might not be so keen when you read the last few on copeland scroll that you missed last night
Unless you gonna do the taste test anyway !If the World did not Suck, We would all fall off !
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22-08-2011, 03:31 PM #28
Re: Ice building up
To diagnose this correctly i will need a bit more detail, but straight away i am concerned with the suction/discharge pressures.
So to correctly identify i need the following information:
Suction pressure
Discharge pressure
Superheat
Subcooling
Full model no of unit (indoor and outdoor)
Airflow
Filter condition
Any ductwork fitted
Refrigeration charge
Application (ie data centre etc etc)Rob Woodworth
GEA Denco Technical Support
rob.woodworth@geagroup.com
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22-08-2011, 08:19 PM #29
Re: Ice building up
how old is the unit, gas could be contaminated, mositure, or a break down in a compressor, dirty gas
also not tryna be patronising, but you charged with 300grams of r22. is the system r22, or 407c?
if gas charge is ok , and your getting to heat absorbed in evaporator the gas could be bad!
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25-09-2011, 12:09 PM #30
Re: Ice building up
1. It could be `cause of either or combination of 2 reasons I understand this to be as overcharge of refrigerant. Please let us know the ambient air temperature around the condenser. Also, you must release some gas from the suction side and check. Also, mention if you find Ice on the compressor body as well.
2. Please check your expansion valve. Many a times, you`ll find the expansion valve flooding and this will result in such situations.
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25-09-2011, 12:22 PM #31
Re: Ice building up
Rajeev
Welcome to RE
Instructing people to release refrigerant to atmosphere is certainly not in line with best practices . Never mind the legal implications.
We as professionals have an obligation to ensure best practices are adhered to ,be it moral or legal , irrelevant of location .
Cheers
StuTool's ? check ! Condom's ? check !
If you can't fix it , f*ck it !!!
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25-09-2011, 12:26 PM #32
Re: Ice building up
weve not had an update since 16/8 so hes either fixed it or blew himself up overcharging it!!
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25-09-2011, 01:22 PM #33
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25-09-2011, 02:57 PM #34
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25-09-2011, 08:51 PM #35
Re: Ice building up
doyour job properly or get a professional.
de gass the split!!! pressure test and triple vac!!! its sounds like you have a blockage if you arent having airflow issues. while on pressure test clean condensor coil and evaporator!!!! if your throwing 300gramm of r22 in you shouldnt be working on the unit imo, perhaps 15 years ago, not these days
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16-10-2011, 09:59 PM #36
Re: Ice building up
dear sirs
i am not a reefer technician but my situation warrants an immediate solution so i seek your professional help.15102011257.jpg
we have done initial precooling to -20C before loading the -18C products. however after 20 hrs of cooling only -9C was reached, compressor covered in ice and sight glass white with bubbles. shud i unload and return to the cold stores? kindly advise
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17-10-2011, 01:53 AM #37
Re: Ice building up
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17-10-2011, 09:28 PM #38
Re: Ice building up
thank you very much. will do so as advised