Oil Cooling Refrigerator Compressors

[Kompulsa]

Hello.

I can't find how to oil cool my two 1/4 HP R 134a refrigerator compressors in the books I have. Each of them has two tubes at the bottom on the side. When I turn them on, nothing comes out of them. I guess I am to use an external pump to pump oil into one of the tubes, and then it will come out through the other and I should just keep circulating it through a radiator?

The oil tubes appear to be totally separate from the refrigerant lines.

[mikeref]

Discharge goes out to a split condenser, so about the first 25% of condenser, then back through the oil cooler/heater and back to the condenser again.

[mbc]

condenser has 2 part .
first part = discharge gas goes there and after cooling down , goes to bottom pipes ( those not important which one) and then goes for 2nd part to cool and become Refrigeration liquid .
it should connected to cool the oil especial in hot area .

[Kompulsa]

So the pressure differences of the refrigerant loop cause it to move somehow?

This is a DIY project, so I guess I will use an oil pump and do what I said then. I guess the oil in that part is separate from the oil in the compressor sump?

It just cools the motor, right?

[Brian_UK]

There is no oil in those 'oil' pipes.

They are simply a loop of pipe within the oil sump of the compressor.

[Kompulsa]

There is no oil in those 'oil' pipes.

They are simply a loop of pipe within the oil sump of the compressor.

Now that was helpful. So it is normally refrigerant that circulates through it then?

[Brian_UK]

Now that was helpful. So it is normally refrigerant that circulates through it then?

That's correct.

Short Tecumshe document,,,,
http://www.hvactroubleshootingguides...and-tubes.html

[monkey spanners]

Gas comes out the dicharge pipe, then though some of the condenser (or could be piped around the door frame in a freezer to stop door sticking instead) then goes back to the compressor and through the loop and then off to the rest of the condenser.

You don't need to used them for the compressor to work, but they may be needed in certain applications.

[mikeref]

Now that was helpful. So it is normally refrigerant that circulates through it then?

There is only high pressure vapour that runs through oil circuit. No oil pump and no direct contact with compressor oil.

[r.bartlett]

There is only high pressure vapour that runs through oil circuit. No oil pump and no direct contact with compressor oil.

how does that cool the oil?

[Kompulsa]

I think he was talking about cold refrigerant vapour from the evaporator. That often under high pressure as well.

[monkey spanners]

Pic half way down link shows oil cooling loop,

http://www.danfoss.com/NR/rdonlyres/...mpressorUK.pdf

[mikeref]

how does that cool the oil?

Oil cooling circuit is just a tube that runs through the bottom of compressor, in the oil. Discharge does a circuit but comes back still warm and if the compressor oil is hotter than the gas running through, then the oil gives up heat. Works in reverse as well so oil is heated if compressor is not warm enough.

[mikeref]

I think he was talking about cold refrigerant vapour from the evaporator. That often under high pressure as well.

Absolutely nothing to do with the evaporator or low side pressure. It is about maintaining reasonable oil temperature of the compressor. Some compressors have oil cooler circuits and others don't. Just don't run discharge pipe straight to oil cooler as compressor won't like it.

[knighty]

do you really need oil cooling on small compressors like that ?

fan blowing over compressor not enough ?

if that's not enough, thermal epoxy a few heat sinks to the outside case ?

[Kompulsa]

Oil cooling circuit is just a tube that runs through the bottom of compressor, in the oil. Discharge does a circuit but comes back still warm and if the compressor oil is hotter than the gas running through, then the oil gives up heat. Works in reverse as well so oil is heated if compressor is not warm enough.

Thank you.

[r.bartlett]

do you really need oil cooling on small compressors like that ?

fan blowing over compressor not enough ?

if that's not enough, thermal epoxy a few heat sinks to the outside case ?

Usually just for freezer compressors

[r.bartlett]

Oil cooling circuit is just a tube that runs through the bottom of compressor, in the oil. Discharge does a circuit but comes back still warm and if the compressor oil is hotter than the gas running through, then the oil gives up heat. Works in reverse as well so oil is heated if compressor is not warm enough.

I have only seen them using the liq line not on a split condenser..