Bad Turbashed?

[jpsmith1cm]

Still battling the Compound cooling problem I posted about a few weeks ago.

The problem comes back to oil flow.

The system is almost saturated with oil. Every gauge connection sprays oil when you hook up to it, yet my turbashed isn't separating enough oil to return to the pumps.

I don't have a complete history on the system, but talking to a manager who has been in the store since the late 90s possible 2000, she said that they have had a problem with oil trips since then, so 10 years of oil problems.

For those who didn't read my previous post, find it HERE (http://hvac-talk.com/vbb/showthread.php?t=648811)

Now, I pumped out and checked the inside of the Turbashed with an inspection camera and broke it in the process.

I've got motor barrels full of oil, sumps the fluctuate with oil level and almost never a level in the turbashed.

I did find that the A9 receiver pressure regulating valve was dumping hot gas on the receiver and got that corrected.


I guess the question boils down to: Has anyone ever had to replace a Turbashed?

I've ordered a Temprite 928R

[thefreezerguy]

Well JP, I have heard the term TD rack for years and I am not sure that I know which racks the term is for (call me ingnorant I guess). Is it the hussmann compound rack set up? Carlyle low end, with interstage pressure, piped to the medium temp rack suction?
Is so, Then YES, I was involved with one turbashed failure. It was in a Costco. Heres what would happen. The low end Carlyles would fill up overnight with oil. It would be so bad that compressors would fail weekly by breaking rods, valve plates, etc.
The walk in freezer had 2 ten ton coils. these would fill up with oil during normal run. then go through electric defrost, THEN LOOK OUT!!! You could see the oil come back, then hear the compressors as the oil hit them that fast.
We ultimately condemned the turbashed. Replaced it with an AC&R separator/high pressure reservoir unit. After pulling out countless gallons of oil, problem solved.
We did cut open the old turbashed to find a funnel looking piece if metal that separates the oil had broken loose from the sides. It looked as if it was originally spot welded into place.

[icemeister]

I've never replaced a Turbashed oil separator, but then when you think about it, what can go wrong with them...really? There's no moving parts in there, so other than cleaning what else is there?

Unersized maybe.

It's possible if you have a severe oil pumper on that rack the separator can't handle the high oil flow rate, so the remainder gets blown out into the system.

[cold spell]

I've never had to replace one due to oil problems, but I have replaced them in remodels. And inside there is a screen along the wall that could get plugged with burnt oil and cause problems.

In the past, on 2 stage racks, the cure to oil problems was to run zerol 150. Seemed to cure a lot of problems.

Im not sure a temprite would be my choice of replacement unless I lived right next door and had a pile of replacement filters and ball valves to isolate it.

Keep us posted.

[icemeister]

...We ultimately condemned the turbashed. Replaced it with an AC&R separator/high pressure reservoir unit. After pulling out countless gallons of oil, problem solved.
We did cut open the old turbashed to find a funnel looking piece if metal that separates the oil had broken loose from the sides. It looked as if it was originally spot welded into place.

Well, there's a good example of what can go wrong with a Turbashed. I hadn't thought of that one.

[thefreezerguy]

Well, there's a good example of what can go wrong with a Turbashed. I hadn't thought of that one.

With the exception of this one failure, I have yet to find a turbashed fail.

[cmclifton]

Well, there's a good example of what can go wrong with a Turbashed. I hadn't thought of that one.

Sounds a lot like a case of friday evening or monday morning assembly. Bad welds or whatever. Still, if I had my druthers, Turbashed would be the only oil separator there is. Temprite ought to go the way of Yugo.

[jpsmith1cm]

Got an update on this job that has turned things upside down yet again.

A tech was on the job again today and for whatever reason, decided to vent the crankcases to suction for some reason. To do this, he opened up all of the oil equalizing lines and then vented that small 'header' to the suction header.

This jump started oil feeding and the rack started to function more or less correctly.


:anyone::anyone:


Who can I :callpro:

[icemeister]

This kinda tells me at least one of those compressors has a lot of blow-by.

The equalizer pressurizes the other crankcases as well. The motor ends fill with oil because the oil check valve between the crankcase and the motor end is forced closed, preventing normal oil return.

Venting the equalizer line to suction lowered the crankcase pressures low enough to allow for the oil to flow normally.

[jpsmith1cm]

This kinda tells me at least one of those compressors has a lot of blow-by.

The equalizer pressurizes the other crankcases as well. The motor ends fill with oil because the oil check valve between the crankcase and the motor end is forced closed, preventing normal oil return.

Venting the equalizer line to suction lowered the crankcase pressures low enough to allow for the oil to flow normally.

We've tested all of the compressors for bad valves and crankcase pressurization.

Thoughts on a bad 'Y' valve pushing too much oil into crankcases and pressurizing them externally?

[icemeister]

...Thoughts on a bad 'Y' valve pushing too much oil into crankcases and pressurizing them externally?

I would think the oil floats would prevent that...unless you exceed their pressure differential limits because the Y valve is stuck wide open. I dunno.

I can imagine a scenario where the oil reserve disappears from the Turbashed and the Y valve starts blasting hot gas which pressurizes the crankcases. But what would trigger that?

I'm thinking that new separator may well solve a lot of problems.

[jpsmith1cm]

Am finding out more and more.

This store has employed a number of different service companies over the years.

When we took over the store, the oil that was drained out of the compressors came out in clumps.

Apparently, maintenance is a word those companies don't quite understand, and now we are stuck dealing with their messes.

When I was there, I pulled an oil sightglass and cleaned a hardened scale off of it that I've never seen before. Under that, the glass itself was heavily etched.

[pherman]

Am finding out more and more.

This store has employed a number of different service companies over the years.

When we took over the store, the oil that was drained out of the compressors came out in clumps.

Apparently, maintenance is a word those companies don't quite understand, and now we are stuck dealing with their messes.

When I was there, I pulled an oil sightglass and cleaned a hardened scale off of it that I've never seen before. Under that, the glass itself was heavily etched.

:eek2: Wow

[engineerdave]

Can I jump in here?

Couple things I might look at....

There's mesh inside the Tubashed. If the mesh is fouled / gooked up, poor separation. I've dealt with that by removing sightglass and reaching in there with a pump-up sprayer wand & solvent. I know that sounds 'hack' but it worked for me.

Think I'd also take a closer look at whatever is regulating your oil pressure. OCV valve, Y valve, etc. Your oil reserve is at Head pressure and can easily overcome the floats on your compressors.....

Also, I'm not sure you'll be real pleased with that Temprite. Things are kinda labor / maintenance intensive.

Hope that helps bud.

[jpsmith1cm]

Figured that I would bump this and give a bit of update.

We found that the Y-valves weren't holding a good setting. I would set them to 17# and, some time later, the pressure setting would be higher or lower. Not by a pound or two, but we'd see 30-50#differential after setting the valves.

We finally replaced them and dialed the new ones in to 17# differential.

The other issue seems to be icing cases and poor oil return due to that.

I also think that high superheats are a factor in the poor oil return.

[jpsmith1cm]

engineerdave,

I already had the turbashed glasses off and poked an inspection camera in there. The horizontal screen/mesh was clear. I was worried that there were screens or baffles higher up inside the top part that were clogged somehow.