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albertjoseph
08-05-2008, 06:47 AM
I have a Acson Ducted Blower fitted with twin cooling coil supported by 2 nos. of TXV. The designed cooling capacity is 200,000 btu/h and connected to 2nos of 100,000 btu/h condensing unit.

The first condenser working in good condition with suction pressure of 65psi and 260 psi for discharge.

The 2nd condenser works fine initially with the pressure of 56 and 270psi. After few hours of operation the compresser/suction line began to freeze until the suction pressure drop to 50psi. I have set the low pressure switch to 20psi to prevent premature cut but after long hours it trip. I could not be there for the entire day to monitor the situation.

The TXV has been replaced, vaccum the system and recharge the R22 gas but the problem still persist.

For your info the condensers located at roof top without oil separator.

Guys, Any idea to solve this problem.

Thank you.

moideen
08-05-2008, 08:17 AM
hi albert

Check the indoor blower rotation and check the any restriction in duct

brianubaldo
08-05-2008, 01:22 PM
I have a Acson Ducted Blower fitted with twin cooling coil supported by 2 nos. of TXV. The designed cooling capacity is 200,000 btu/h and connected to 2nos of 100,000 btu/h condensing unit.

The first condenser working in good condition with suction pressure of 65psi and 260 psi for discharge.

The 2nd condenser works fine initially with the pressure of 56 and 270psi. After few hours of operation the compresser/suction line began to freeze until the suction pressure drop to 50psi. I have set the low pressure switch to 20psi to prevent premature cut but after long hours it trip. I could not be there for the entire day to monitor the situation.

The TXV has been replaced, vaccum the system and recharge the R22 gas but the problem still persist.

For your info the condensers located at roof top without oil separator.

Guys, Any idea to solve this problem.

Thank you.
did the ice reached the compressor?
do you have a suction accumulator?
if not yet, just modify the design.. install one.
if you have installed already and unit still the same.
is this happen only if the unit is in lower temp(negative deg. celcius?).
is your txv size is fit in your system?

powell
08-05-2008, 03:11 PM
Hi Albert,

First question. What is the history of the unit? Did it work ok before or has it always iced up?

Here are some commom reasons for low suction pressures.


1. Light load conditions. Does this system have any type of unloaders?
2. Compressor oversized and the evaporator is undersized.
3. Evaporator coil is icing.
4. Poor distribution of refrigerant thru the evaporator nozzle and circuits. Usually the bottom rows of the evaporator will freeze up when this occurs. There should be no more than 5 degrees F difference in the superheat between any two circuits as they enter the header.
5. Uneven or inadequate evaporator loading due to poor air distribution. Poor duct design.
6. Excessive accumulation of oil in the evaporator.

Brian_UK
09-05-2008, 12:28 AM
Are the coils interlaced or is it one coil after the other?

sptyagi
09-05-2008, 06:59 AM
pl check is there any filter in suction which may be cloged. secondly refrigrant quanitity may be less.

RANGER1
11-05-2008, 12:45 PM
I would suggest checking both indoor and outdoor coils for dirty/blocked coil blocks. A torch on one side of coil block should see light on other side.
Over time maybe filter condition had deteriorated causing dirt etc to build up in fins.You must be able to see through,probably on an angle as pipe circuit will dictate which angle.

brianubaldo
16-05-2008, 02:48 AM
:off topic: the poster is not replying for the information..

hendry
18-05-2008, 05:10 AM
Hi albertjoseph,

normally, when i see my compressor has such signs, i'll check my evaporator for any possible lacking in heat exchange.

in your case, it is a air cond indoor blower, there are many components which may contribute to this.

i'll check everything in the blower to make sure it stay clean & clear.

hope that helps.

Hendry, on wesak day holiday.