New compressor overheating

[kurt s]

i just installed a New scroll compressor on a AC roof top unit. it is i believe around a 100,000 Btu unit.
R22 refrigerant. 3phase 120/208 electric . Run load amps (RLA) 37. the old compressor was grinding away and making alot of noise and not pushing out any psi.

so i installed the new compressor and when i started the unit and began to charge the system (R22) it was making a lot of noise.

the compessor was very loud and getting very hot fast. so i started adding the refrigerant faster to give it more superheat to cool it.

i was worried it was to loud and was going to over heat so i shut it off, then when i started it up it would run but it seemed to be locked up. the suction psi wouldn't come down while running, and the high side gage not going up at all.

than it overheated and went out on thermal overload.

i think i may have slugged the compressor with R22??

any ideas ?? i also may have made a mistake by adding some R22 to the discharge side of the unit to double check for leaks after i vacuum tested it.
than i began the charge and it was loud and hot..!!

[wambat]

Three phase scrolls can rotate in either direction depending on how it is wired. If running in reverse rotation the compressor will have elevated sound levels, reduced current draw and suction pressures will not drop along with a non rise in discharge pressure. The compressor will eventually trip on motor protector. If it was new you should have some installation instructions, Didyou read them?
P>S> Where did you find 3 phase 120Volts? Did you meam 220/208?

[tony--1]

its running the wrong way by the sounds of it . you know by the sound if it running right or wrong . and you get no pressure drop in suction and no discharge pressure . did you switch it off or just leave it running ?

[tony--1]

it makes no differance that you charged it thro the discharge you can only get so much gas in that way . i take it your not a engineer ? .

[NoNickName]

You can't fill through the discharge. The high side has a higher pressure than the cylinder. This is a hint that the compressor was running the other way around...

[Burrah Boy]

Definately sounds like its wired wrong way round. Cant charge on discharge side!

[tony--1]

he had pull a vac in system he can add gas to high side. low side anywhere as long as its not running

[paul_h]

Yeah filling liquid into the high side while in vacuum to get the charge up to estimated 50% then waiting a while before starting the compressor is the right way to do it.
edit: or a full charge weighed in if you know what it is.
It won't damage the compressor as liquid won't go into it, and it gets some refrigerant into the system so it won't run short and hot for so long while charging vapour into the suction.
It's either going the wrong way as others suggested, or has a refrigerant flow problem or a voltage supply problem (which may have caused the original compressor to burn out), or you have a faulty compressor.

[kurt s]

thanks guys i will keep you updated, i wont be able to work on it again for the next 6 days. im sure i wired it correctly but maybe i did get a wire wrong. it seemed to be pulling in some refrigerant on the suction side but it just wasnt the amount i thought it should be.

it had proper voltage comming from contactor, and was pulling 32 amps. maybe the copacitor? and contactor should be changed out. i may try that next.

[NoNickName]

Yeah filling liquid into the high side while in vacuum to get the charge up to estimated 50% then waiting a while before starting the compressor is the right way to do it.


No, it is not.

[paul_h]

No, it is not.So you run a compressor with no refrigerant in it, or charge liquid into the suction side?

[nike123]

If that is heat pump and phase sequence is OK, then it could be that reversing valve is faulty (bypasing suction and discharge), hence noise and not much pressure difference.

[nike123]

No, it is not.
What is reasoning behind this statement?

[wambat]

give comp model# because 3 phase doesn't normally have a capicitor

[NoNickName]

So you run a compressor with no refrigerant in it, or charge liquid into the suction side?

Liquid goes into the liquid line, vapor goes into the suction.
Charging liquid in the discharge may cause instant and violent flash, and when there is barostatic valve or check valve, it may be damaged.
Even worse when the discharge goes into an oil separator. Oil will be diluted with liquid refrigerant, carried over and returns to the compressor from the suction.

[WINJA]

give comp model# because 3 phase doesn't normally have a capicitor
COULD BE POWER FACTOR CORECTION CAPACITOR.

Also he could have changed a perfectly good compressor, i went to a site where the main switch was changed and the retard:confused: electrician :confused:got two phases mixed up and all the scrolls and pumps were running backwards, so his first diagnoses could have been a rev rotation compressor :confused:

[paul_h]

Liquid goes into the liquid line, vapor goes into the suction.
Charging liquid in the discharge may cause instant and violent flash, and when there is barostatic valve or check valve, it may be damaged.
Even worse when the discharge goes into an oil separator. Oil will be diluted with liquid refrigerant, carried over and returns to the compressor from the suction.Some of us work on unit's without liquid valves, and work on refrigerants that need to be charged with liquid.
So we break your rules every day, sometimes even liquid charging into the suction before starting as there is no other port, and it doesn't harm the units, it's to manufacturers spec.
edit:
But never mind, after reading the OP again, this was a larger unit, only vapour was added to the discharge for pressure testing, and most of the charge was aded via the suction after the compressor was running, so the point is moot.
I'm used to small units where you have to charge into whereever the one service port is. Usually in winter when the units are going to start on heat, you are charging into what is going to be the discharge port. In summer it's going to be the suction port.

[tony--1]

SH IT iv started sumthing here. on the packs i work on we just dump liquid into the liquid reciever before starting . about 500kg or so . charging in thro the suction you would be there forever . i said you can put gas in anywhere meaning just to hav a bit of gas in the system be4 you run things up .

[NoNickName]

on the packs i work on we just dump liquid into the liquid reciever before starting .

This is correct.

[tony--1]

The post does not say that he added liquid or vapour

[NoNickName]

The post does not say that he added liquid or vapour

Liquid in liquid receiver, he says.

[The MG Pony]

thanks guys i will keep you updated, i wont be able to work on it again for the next 6 days. im sure i wired it correctly but maybe i did get a wire wrong. it seemed to be pulling in some refrigerant on the suction side but it just wasnt the amount i thought it should be.

it had proper voltage comming from contactor, and was pulling 32 amps. maybe the copacitor? and contactor should be changed out. i may try that next.

when does a 3ph have a start cap? that statment is confusing are we dealing a single phase or 3 phase?

[nike123]

R22 refrigerant. 3phase 120/208 electric .


Yet, 120/208 voltage is little bit odd statemant!:D

[scottishladx]

when charging 407 etc i weigh it in, let it rip through the high side until it equals out then slowly add through suction just a few psi above running pressure or give it a few squirts until correct charge is applied on a/c.

I have ad no probs doing it this way.

[kurt s]

Update, some of you were correct as i thought also a wire was crossed.

changed wirring and it ran fine for a minute or so.
than it stopped working.!!!

a large slug of oil came back to the compressor and it would not pump. try again tomrrrow.

any ideas why all that oil would come back to the compressor?

[icecube51]

when you start to work on 3phase units its preferable you look for a phasemeter,its a kind of multi-meter but it can tell you the phase yore working on. by doubt you take the measurement on the the main bord,note the phase from the bord and execute the same on the unit.than you are sure the wirings are correct.
if yore compressor is blocked you can switch a phase an let it run for 1 or 2 seconds and then change the phase again,until its deblocked.

Ice

[WINJA]

correct.
if yore compressor is blocked you can switch a phase an let it run for 1 or 2 seconds and then change the phase again,until its deblocked.

Ice
Do you mean seized?

[icecube51]

sorry but my English is not that good. i don't understand "seized ". :confused:

Ice

[nike123]

sorry but my English is not that good. i don't understand "seized ". :confused:

Ice


To cohere or fuse with another part as a result of high pressure or temperature and restrict or prevent further motion or flow.

[icecube51]

OK thnx Nike123, that is just what i mean,so if it is seized,try to switch the line's of current . change 1&3 so it will go backward and then change it again. maybe you have to do this more than once,but if the damage is restricted it can work again.
and if it does work again,take you're time to check things out.

Ice

[Richvacr]

So we break your rules every day,

How about charging into the evaporator. Have a unit where manufacture says put 4# into receiver then start up and charge the rest into access port before distribution tubes. I put in 20# liquid R134a.

I don't like much about these units but I like this.

[NoNickName]

In fact most of you also break compressors every day. What is #?

[paul_h]

In fact most of you also break compressors every day. What is #?
That's a nice statement! Care to back that up? I've never broken a compressor or a/c for that matter.
# is pounds, (lb)

[NoNickName]

That's a nice statement! Care to back that up?

Care to come and see how many break down on day 1?

[paul_h]

What does that mean? I used to do warranty support and fix them (after factory charging, so no one charged them 'the wrong way previous'), and I was responsible for them for the remaining 5 yr warranty.
I never had to go back due to a compressor I replaced breaking later on.

[nike123]

What does that mean? I used to do warranty support and fix them (after factory charging, so no one charged them 'the wrong way previous'), and I was responsible for them for the remaining 5 yr warranty.
I never had to go back due to a compressor I replaced breaking later on.

You both speaking about personal experience.

Paul you maybe not ever done damage to compressor, but as NoNicName said, there are many cases of overcharging and damaging compressor during first charge because of bad charging practice.
I witnessed some (when I worked as electrician in one small air-conditioning factory here) during first charging, and stupid technician has always blamed compressor manufacturer (Copeland) for that.

I am sure that NoNickname said that with good reason.

[paul_h]

I am sure that NoNickname said that with good reason.NoNickName rather arrogantly said

In fact most of you also break compressors every day.
Just because he doesn't work with systems that have no reciever or liquid line acess port, so is ignorant about split systems.

[NoNickName]

I said that with a reason. Compressors either die on day 1 or after many many years of good operation. The reason is within badly trained engineers who charge the system exactly as explained. It doesn't matter whether the system has the liquid receiver or not. Rules are to be abide to by everybody.
I didn't imply you were ignorant, I said exactly the opposite: I affirmed you know what you are doing, and it's wrong.

[h.aboughazala]

when you work with scroll compressor with 3 phase you must checking about the correct phase direction and for your problem i belive that noise and fastover temperatuire at compressor with starting because the phases at wrong position

[acdoc]

Paul h hit it right on the money.

[JUANABELLA]

Pls check the filter drier , did you change it?

[hhbref2006]

i just installed a New scroll compressor on a AC roof top unit. it is i believe around a 100,000 Btu unit.
R22 refrigerant. 3phase 120/208 electric . Run load amps (RLA) 37. the old compressor was grinding away and making alot of noise and not pushing out any psi.

so i installed the new compressor and when i started the unit and began to charge the system (R22) it was making a lot of noise.

the compessor was very loud and getting very hot fast. so i started adding the refrigerant faster to give it more superheat to cool it.

i was worried it was to loud and was going to over heat so i shut it off, then when i started it up it would run but it seemed to be locked up. the suction psi wouldn't come down while running, and the high side gage not going up at all.

than it overheated and went out on thermal overload.

i think i may have slugged the compressor with R22??

any ideas ?? i also may have made a mistake by adding some R22 to the discharge side of the unit to double check for leaks after i vacuum tested it.
than i began the charge and it was loud and hot..!!
In the first place ,your old compressor may have been damaged because of a blockage in the system. Prior to replacing the new compressor, you should have tested the rest of the line to find where there is a free flow of refrigerant from one side to the other.

Cetainly, noise will result from a noise a blockage and then die down. What about the filter drier, you should always replace it when you are changing compressors. The phases may have been wrongly connected, which may be the cause for overheating. You should also ensure that you clean the rest of the system prior to replacing the compressor