Please Help

[Riaancam]

Hi can someone help . my hobby is to repair fridges and now I have hit a snag . I have fitted a new compressor on a defy fridge freezer and now it keeps on freezing up . what is the reason for this ,I have changed the thermostat already and my 134a gas pressure is 2.5bar(35psi)

[liamriley86]

May be that your compressor is too largly sized for your other components and the suction pressure is too low? Is the compressor exactly the same as the origional one? What was the problem to make you think it was the compressor was faulty? I only ask as you say its your hobby and you may not be fully trained in refrigeration. Does it have an expansion valve as I cant picture the system you talk about if so the superheat setting may need looking at as liquid back could cause compressors to fail! Ihope this helps buddy let me know how you get on;-)

[Gary]

I have fitted a new compressor on a defy fridge freezer and now it keeps on freezing up

What is the "it" in the above sentence?

Also define "freezing up". Do you mean "it" is frosting?... or do you mean "it" is locking up?

[Riaancam]

Hi, the compressor was burnt out dew to power surge . the size of the compressor is 1/4hp Samsung domestic the same as the original compressor . this fridge is a domestic 450L twin door fridge freezer (top and bottom) . this fridge has got a capillary , I have changed the compressor , pulled vacuum and recharged with 134a to a pressure of 2,5bar (35psi), I want to know what are the ideal pressure.

I am not trained on refrigeration . it is my hobby

Thanks for the help

[johnnychin]

Might be something wrong with the valves

[Riaancam]

Hi , it means the fridge and freezer compartment frost up (+-40mm).

sorry for my poor eng I am form RSA and are Afrikaans speaking

thanks for the help

[Gary]

Did you weigh in the charge?

[Riaancam]

No ,I don’t have a scale that can measure that small amount of gas, I normally work on the pressure of the gas in the unit and it normally work for me , i learn from trail and error

[Gary]

Charging by pressure is the worst way to charge a system. You have put way too much refrigerant in the system.

[Riaancam]

Gary, can you explain the correct way to charge a fride and what type of scale do i need

thanks

[coolstuf]

Hi Riaan,

You have to charge by weight. The charge weight is normally given on the info plate in grams or kg. Invest in an electronic scale you can buy from any fridge supplier, well worth the money. Make sure you charge in liquid form.

Sterkte!

[monkey spanners]

Hi Riaan,

You have to charge by weight. The charge weight is normally given on the info plate in grams or kg. Invest in an electronic scale you can buy from any fridge supplier, well worth the money. Make sure you charge in liquid form.

Sterkte!


As coolstuf says, except you can charge R134a in vapour or liquid, vapour would be easier on a small fridge :)

[tonyelian]

hi
as a domestic fridge low side must be between 0-5 psi
35 psi too much refrigerant or bad valves

[coolhibby1875]

this is way over charged you need to recover the gas and weigh it in properly or you will have nothing but problems!

[Andy]

Hi can someone help . my hobby is to repair fridges and now I have hit a snag . I have fitted a new compressor on a defy fridge freezer and now it keeps on freezing up . what is the reason for this ,I have changed the thermostat already and my 134a gas pressure is 2.5bar(35psi)

Hi Riaancam:)

did you charge to 35psi before running the compressor.
I don't believe you could get that pressure in the suction with the compressor running.

Kind Regards Andy:)

[Riaancam]

the compressor was running.

[Riaancam]

Thanks for all your help

I bought a scale and will work with a scale in the future .what is the best way to charge a fridge "compressor on or off" and "liquid or vapour"