Ice building up

[Karlsen]

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!

[chillerman2006]

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 shooting

[Karlsen]

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..

[chillerman2006]

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..

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 thermometer

[Karlsen]

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.

[Gary]

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.

Sounds like an evaporator airflow problem to me. Try cleaning the evaporator coil and the blower wheel.

[chillerman2006]

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 out

[Gary]

everything going wrong tonight, have been doing three things at once

I know how that works. If I try to walk and chew gum at the same time, I trip over my own feet and choke on the gum.

[chillerman2006]

I know how that works. If I try to walk and chew gum at the same time, I trip over my own feet and choke on the gum.

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-work

[Karlsen]

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

[mikeref]

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?

[Karlsen]

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?

[andisaios]

Is the compressor manufacturer or a smart guy has replaced by a biger one??

[Gary]

Suction temperatur measured with IR-Termometer = -14 degrees.

Get a real thermometer (not IR).

Measure the temperature of the air entering the evap coil and the temperature of the air leaving the evap coil. These measurements should be taken close to the coil.

[Gary]

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.

[Karlsen]

Manufacturer compressor

[Karlsen]

Thanks, will do more research on air flow than..

[andisaios]

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

[r.bartlett]

This should be fairly easy to solve. Perhaps take another engineer for assistance..

[benijoseph]

Mr, K N.

IF POSSIBLE CHECK PRESSURE ON BOTH SIDE OF THE EVO IN & OUT IT SHOULD BE SAME!

rgds.

[chillerman2006]

Get a real thermometer (not IR).

.

Just throw that IR & listen to Gary

GET A REAL THERMOMETER

You cant take temperature with a ir thermometer its just rough guidance on surfaces

And Jack Diddly on Air

Or as already told "call an engineer"

[install monkey]

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!

[install monkey]

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

[chillerman2006]

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!

Or failing that its time for "Super Vector"

[chillerman2006]

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

You beat me to it !

[install monkey]

whilst posting, my cake muncher is watching east enders -ur the ian beale of RE haha

[chillerman2006]

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 !

[Denco Technical]

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)

[sweimaker]

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!

[Rajeev Prasad]

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.

[stufus]

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.

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
Stu

[install monkey]

weve not had an update since 16/8 so hes either fixed it or blew himself up overcharging it!!

[chillerman2006]

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
Stu

Well spotted Stu

thats probaly why you cant get any cold food/drink from the corner shops here

R's chillerman

[stufus]

Well spotted Stu

thats probaly why you cant get any cold food/drink from the corner shops here

R's chillerman

No comment !!

Cheers
Stu

[sweimaker]

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

[fercmal2]

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

[Gary]

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

Defrost it.

[fercmal2]

thank you very much. will do so as advised