Is the compressor dead?

[krasi_k]

2 ton Copeland scroll compressor, 7 years old. Runs only 20 sec in hot day and the overload cuts off. Low pressure stay about 100 high 160. Colder day or night time runs continiosly but the lo and high are still 100/160. Both coils are clean, condenser fan runs good. The return pipe never gets cold. Is the compressor dead??

[cobitech]

It's dead.

[krasi_k]

Thanks. I just bought a new one.

[hvac r us 2]

The question I always ask my guys is "why did it die?"

Make no mistake a 7 year old compressor just didnt die, it was murdered!

Dont let anybody kid you, there is a reason that compressor failed and it's not becuase it was defective, old age, a lemon, hit by lightning, voltage spiking...

You know all the popular answers techs give when they really dont know.

Without knowing why the first compressor failed, stands to reason the second compressor will also have the same fate.

Ask yourself,
How much oil is left in the old compressor?
Is the unit mis applied?
Long line not done correctly?
Low ambient not done right?
Wrong metering device?
Bad airflow?
How much refrigerant did you take out, was it overcharged?

You get the idea...the answer is out there!

[krasi_k]

I'll pull the refrigerant Modnday probably has been overcharged. I found a old braizing job on the condenser coil probably the unit leaked out and has been repaired but not in the last 3 years. How long it takes to "die" overcharged compressor? Everything else looks good.

[ct2]

How long it takes to "die" overcharged compressor? Everything else looks good.
>--------------------------< usually about this long

[trgams]

Is this a heatpump? If so, you could have a stuck reversing valve letting hot gas bypass back to the compressor and overheating it...your pump might be OK, but I would suggest further diagnostics..Good-Luck.

[Swampfox]

Check the oil for a green color to it, you might have a mess in there

[krasi_k]

not a heat pump. If the oil is green what does that mean?

[trgams]

The green Slime has been Known to infect systems that have gotten moisture in them for one reason or annother...A hole in the condenser coil is one reason why I can think of, also not properly evacuating a system before charging, repairs made in the rain....various reasons. If you do find the slime, it's best to replace the entire system(including the lineset) this will assure you you aren't contaminating the rest of the system with it. I have tried several ways of cleaning this mess up before, and I can assure you from personal experience, It's not worth trying. I hope the green slime has not infected your system. Good-Luck. PS: since you have a straight cooling unit, and your pressure readings indicate your compressor isn't pumping, it's a good bet it's bad. Cheers.

[sean88]

How can you condem a compressor based on one pressure reading? If the compressor where not functioning both hi and low sides would be the same.

Did you ohm out the compressor leads? A high resistance would indicate a compressor going bad.

What were the running amps as compared to nameplate data?

Jump out the low and high pressure switches and see what the pressures do that will tell you if there is a restriction in the line or it's overcharged.

Find out why this one has gone bad, it worked for 7 years, don't throw good money after bad.

[tinknocker service tech]

have to go along with sean88. 100/160 no valves in a scrole to go bad. something else is happening in this system. even if the check valve goes it will still pump just have a loud swriling rattle when it shuts down. what type of metering devise is in the system. i think when you change the compressor you may have the same problem. if the senser is shutting down the compressor it may be defective and not the compressor. recheck the system before you replace it

[trgams]

Originally posted by krasi_k
2 ton Copeland scroll compressor, 7 years old. Runs only 20 sec in hot day and the overload cuts off. Low pressure stay about 100 high 160. Colder day or night time runs continiosly but the lo and high are still 100/160. Both coils are clean, condenser fan runs good. The return pipe never gets cold. Is the compressor dead??

Gentlemen: How in the F*&^ is this guy going to have a compressor there in a straight cooling system and it be good?
On a hot day the compressor runs for a while and overheats this is a fact we know...if the suction pressure was 100 on a hot day even it would most likely be flooding refrigeant back unless it was 100 degrees inside.(assuming the compressor was pumping) and the suction line would be quite cold right? Not to mention the fact that if the compressor was pumping on a hot day the head pressure would be a hell of a lot higher than 160psig. The only way I could see him reading these pressures on a condensing unit that had a functional compressor is if he had his guage manifold cracked and was allowing refrigerant to bypass through his manifold.I may be missing something here, but I think he's got a piece of trash in the pressure relief, or there is junk in the scroll itself. Not trying to slam anyone here, just putting out an educated guess. Good-Luck.

[krasi_k]

Ok. I have replaced it. There was about 56oz r22 instead of 73oz according to the label on the condenser. When I checked for leaks I found one on the pipe entering the condenser and probably that was the problem with the unit and my old compressor is not bad. Anyway I did not put it back.

[smokin68]

so it was low on freon and running high suction low head pressures??? Hummmmmmmmmmmmm.

[tinknocker service tech]

so what was the real problem with the unit. subcool auperheat presures and line temps and td. if the old compressor is still good did you charge for the new one or just the repair

[rob10]

Originally posted by hvac r us 2
The question I always ask my guys is "why did it die?"

Make no mistake a 7 year old compressor just didnt die, it was murdered!

Dont let anybody kid you, there is a reason that compressor failed and it's not becuase it was defective, old age, a lemon, hit by lightning, voltage spiking...

You know all the popular answers techs give when they really dont know.

Without knowing why the first compressor failed, stands to reason the second compressor will also have the same fate.

Ask yourself,
How much oil is left in the old compressor?
Is the unit mis applied?
Long line not done correctly?This is one. Poor filter maintenance could be the culprit.
Low ambient not done right?
Wrong metering device?
Bad airflow?
How much refrigerant did you take out, was it overcharged?

You get the idea...the answer is out there!

[cobitech]

smokin68
Professional Member

Registered: Jun 2003
Posts: 1332
so it was low on freon and running high suction low head pressures??? Hummmmmmmmmmmmm.
__________________
Is it really any easier doing it twice?????




Hmmmmmmmmmmm is right......doesn't sound like a low charge would give you the pressure reading that you posted.

I think there is something else to this,don't you?

[trgams]

I'm So CONFUSED!!!!!!!!!!!!!!!!!!!!!

[tinknocker service tech]

mistake or not one thing i can say once you burn out a compressor it is history and you eat the mistake. putting it back it wont be runnig for long if at all and you just waisted two compressors