How to check a new compressor before installing it ???

[kefah]

Hi
how are you guys
my question is how to check the compressor (before installation) if its faulty or not
bcoz here when u buy anew compreesor
once u install it u cannot return it to the saler in case its faulty or not pumping properly
some experts here do some test to check the compressor before install it
first method is by removing the discharge line plastic plug
and keeping the plug on the suction line then switching the compressor on
for FEW seconds
if the compressor started viberating then its faulty
if its worked properly then its OK

the second method (-which the saler will not retun it) is by welding a service valve on the discharge line
then attaching a manifold gauge (with its valves closed) to the compressor discharge line
and switching the compressor and make it pumping to 150 or 200 psi then turning it off
then switching it again to see if its can pump with pressure on it>if its pumped its ok
if its not then its faulty.

sorry for my broken english

[FreezerGeezer]

Interesting thread Kefah. :)

As far as I know, in the UK & Australia, if the compressor is Dead On Arrival, you just swap it under warranty. If the supplier checks it over & finds you broke it, then they'll send you an invoice (a bill) for the second new compressor.

[passandscore]

I have ohmed out the windings while still at the suppliers. Had a bad experience and made a habit to take 5 extra minutes to confirm electrical integrity before an installation.

[install monkey]

compressor reliability has improved over the years, not had 1 fail in the last few years, (upon fitting)
a good vac,new electrics/starters etc as good practise,
had ones where the compressor stubbs damaged as its been rattling in the box - but thats apparent when u open up the box- i always inspect inside the box before signing for it

[FreezerGeezer]

Pretty much agree with everyone's comments. It was common where I worked in the UK to megger the compressor on arrival (at our yard if possible) as often a crane would be involved in a compressor change. Then good evacuation. New oil & refrigerant (if required) of course. If the starting gear was quite new & passed a close inspection we might leave it, but almost always we went for the best practice option & just replaced everything. No point taking a chance when a lift in the City of London cost thousands of £ & took weeks to arrange.

We did have one instance where we were replacing a large recip. in a basement around Bristol Docks. The remanufactured comp. was the right duty, but a different body with different arrangement of the heads. We got the blasted thing all the way into the basement by 'walking' it down the stairs with blocks & an A frame arrangement before we realised this and that it wouldn't fit through the hole to get to the chiller!
An important lesson learned to always check the dimensions of the reman. on offer! ;)
In case you're wondering, we couldn't replace it with a new compressor as Trane haven't made a recip. since 1989 or thereabouts.