Oil Sweating

[eipret]

Hi u all, any info on the excesive oil "sweating" on the Copeland ZB38,56 and 75 scrolls at the sump sight glass? Operating in cond. units for Meuller subcool systems for milktanks.

eipret
Southren Cape South Africa

[The Viking]

Sweating, as in splatters of oil hitting the glass?

Or foaming, as in a lot of bubbles in the oil?

If it's foaming, then it's because liquid refrigerant is entering the compressor - check the superheat.

[eipret]

Thx for the reply.. no "sweating" on the outside, the base and sump. New sight glas seals and any improvised materials but within a month it still continue. No comment from the suppliers.

Mooibly ( Best wishes in my lang..)

Eipret

[nike123]

I still don't understand your "sweating".
Did you mean by that that oil leak around sight glass thru the sealant. If that is the case, than could be because the oil in crankcase dissolves rubber sealant.
What type of oil is in there?

[The Viking]

Ok, so it's condensate forming on the outside of the compressor, low down?
If so see my advice about foaming in my previous post.

[Grizzly]

Hi u all, any info on the excesive oil "sweating" on the Copeland ZB38,56 and 75 scrolls at the sump sight glass? Operating in cond. units for Meuller subcool systems for milktanks.

eipret
Southren Cape South Africa

Sweating or iced up, Could mean nothing other than low evaporating / superheat settings or temps.
What are your actual / expected evaporating temperatures.
If something is reducing the heat transfer at the evaporator. Ie blockage reducing air flow (iced up) or the Milk or cooled medium. Has dropped in temperature due to winter ambient settings. Your superheat / suction temps would be lower.
Even the fact that the low ambient reduces the operating head pressure and therefore less heat being introduced to the suction port of the compressor can have a huge effect.
At this time of year (winter here) I have sites that regularly trip on low suction pressure, low evaporating temperature and various other spurious faults. All related to operating temps and pressures being affected by "outside sources" in this case the weather.
Any of the above and more could be the cause.
Go back to basics and check the operating parameters. You may not have a problem with the chiller setup at all.
This is why it's allways a good practice to keep a site log or some details of normal running conditions. It then gives you the engineer somewhere to start from.
Alternatively you may have carried out all of the above and some to still have this issue, you don't say!
Food for thought I hope.
Steve AKA Grizzly

[monkey spanners]

Hi Eipret,

Are you having problems with oil leaking (weeping) from around the sightglass?
I believe these are the one piece sightglasses with the dimple patterned glass fused to the metal, with an 'o' ring.
I have changed about five of them on milk tank cooling systems and have found it important to tighten them using a torque wrench to ensure a leak free seal. Also, i cleaned where the 'o' ring sits back to bright metal.
I think the torque setting is 20 Nm, BUT i recommend that you check with your local Copeland technical representativen as i can't find my notebook.
You will need a special tool to fit in the grooves in the sightglass which also fits a socket set, i've made one out of a suitable socket.
They seem to start leaking around ten years old.

I'd also change all the oil instead of topping up incase the old oil is causing a problem with the 'o' ring.

Jon

[hendry]

yes, i do agree...

terminology is very important in our works esp. when you are doing troubleshooitng over phone/s.

u says this but customer claim other/s.

"sweating" to us, it means condensate water form on the external surface of any equipment in questions.

but "oil sweating" is rather new to me.

since the system is for milk tanks, i feel Eipret may means condensation at the outer surface, which carry the symptoms of liquid floodback or floodstart.

Eipret, could you elaborate your scenario/s. thanks.

Hendry