What symptoms would an overcharged refrigeration system display ?

[lma]

As a matter of educational curiosity ... what symptoms would an overcharged refrigeration system display ?

[james10]

High pressures
poor performance
low superheat
compressor slugging liquid

[monkey spanners]

Also high subcooling.
Higher than normal compressor amps.

[nike123]

OVER CHARGE = Low superheat. Normal evaporator TD. High suction pressure, subcooling, head pressure & compressor current draw.

[ref tech101]

Liquid line cold with the ref. preasures not adding up to its temperature chart..suction iceing to compressor(liquid)...sight glass full,but most inportent is the amps compared with the rated amps..

[lma]

Thanks for the responses. I like the idea of amperage. What exactly determines the amperage a compressor will take ?

[Quality]

Its not what it will take but what it will pull under a certain load

[lma]

you are correct ... what a compressor will pull

[nike123]

What exactly determines the amperage a compressor will take ?

Compression ratio!

[shaaf]

OVER CHARGE = Low superheat. Normal evaporator TD. High suction pressure, subcooling, head pressure & compressor current draw.

if system over charged & being slugging compressor by refrigerant so is suction pressure high or low ?

[Frostyguy]

Over Charged System:

- Wont cause slugging unless you have an automatic txv, or captube system.
- You'll have a higher suction and discharge preasures: If reciever has reached its capacity, or if the recievers internal dip tube has busted. You can have an over charged system in cooler weather and not catch it until ambient rises and full demand is required.
- Yes higher amp draws, but not a good stand alone indication.

-Good indication is all things considered equal, operational, and sized properly, the system operates fine in cooler weather, but doesnt pull temperatures in warmer weather.

[lma]

Thanks Frostguy...what happens if the receiver reaches its capacity in this senario?

[Frostyguy]

Well, once your reciever reaches its absolute capacity, your high side preassure will peg and trip out unit on high limit.

[Gary]

As a matter of educational curiosity ... what symptoms would an overcharged refrigeration system display ?

The question is backwards.

A system does not tell you what's wrong and you determine the symptoms.

A system tells you it's symptoms and you determine what's wrong.

It is a mistake to teach or learn backwards trouble shooting. It just makes the job harder.

[lma]

The question is backwards.

A system does not tell you what's wrong and you determine the symptoms.

A system tells you it's symptoms and you determine what's wrong.

It is a mistake to teach or learn backwards trouble shooting. It just makes the job harder.

Agreed... thats the theory part. However when on the ground we often have to determine the most likely cause of a problem from a given set of symptoms. Knowing the consequences to certain scenarios such as this one helps rule out unlikely scenarios and make an educated guess to what really went wrong.

It is easy to determine an answer to a straight forward question... its more difficult if you have an answer, to determine which question it belongs to.

[Gary]

However when on the ground we often have to determine the most likely cause of a problem from a given set of symptoms.

That's what I said.

In the question, you are starting with the problem and looking for the symptoms.

On the ground, you start with the symptoms and look for the problem.

[Gary]

Here is an example:

If the evep dT is not excessive,

and the cond dT is not excessive,

and the SC is excessive,

and the SH is normal to low,

then what is the problem?

[lma]

Understood.. The reason I asked the question in the reverse format was to look at a different method of determining a cause of a problem. It helps of you know what problem to look for if you have seen a similar problem before and seen the symptoms it displays. So the idea here is.. assume you know the problem for one scenario... an overcharged system for example. What symptoms would it display ?... you list down the possible symptoms and store it in your troubleshooting guide. Then in another scenario... you come across a set symptoms...you can then ask the question... which of the scenarios already studied would most likely cause the set of symptoms seen ... it is then that you can say you have made an educated guess...

[Gary]

The above example is an overcharged system. No guesswork involved, educated or otherwise.

[Gary]

Agreed... thats the theory part. However when on the ground...

I am a retired service tech... on the ground... hands on... fixing everything from fractional HP to 3600 ton centrifugals to cascade freezers to supermarket systems to you-name-it... for 40 years.

There is nothing theoretical about my trouble shooting methods... and I don't guess at what might be wrong or make premature judgements, I follow the trail of symptoms to wherever it leads.

Proper trouble shooting is not looking at a set of symptoms, it is looking at a sequence of symptoms, it is an if/then statement with many branches and sub-branches.

I don't understand why people insist on doing it the hard way.

[nike123]

I don't understand why people insist on doing it the hard way.

It is easy when you found right way.