Already solved problem (another again)

We once had problems with an oilpressostat safety device (OSD)
On the packs we mostly uses (Profroid (Carrier)/France), Profroid mounted them just like Bitzer with a bolted bracket besides the oil pump.

Because it was a negative pack, there were also head ventilation fans mounted.

From one of the OSD, the cover of it was broken or removed (I don't remember this) and the airflow of the fan of the head ventilation was just enough to cool down the heating element whereby the OSD was unable to trip off when it was needed.

We had therefore a broken compressor (no oil in the sump) mounted a new compressor and had a broken compressor again after some days.

The client argued that we hadn't checked his OSD during service some months before. The problem was a faultyTraxoil (electronic oil level system)

Since then, all the racks for this client where changed and we had to order packs now with the OSD on a separate panel.

Better this way Marc?

Hi Peter,
the main problem with oil is to find out WHY it went into the system. carrier`s usually dont throw the oil like bitzer`s do but on a bitzer you can clean the oil filter and on a carrier you will have to take it apart to clean it.

chemi

If I understand properly, you were using traxoil's instead of oil floats on a parallel compressor system. Each compressor also had a mechanical oil failure safety control mounted normally.

The Traxoil float became stuck in the upper position, signalling no alarm and that the compressor had a sufficient oil level in it.

The oil pressure safety device sensed lack of oil pressure, but the head cooling fan would not permit the heater to achieve the necessary temperature to trip the safety contacts?

The Traxoil failure is a familiar one. The oil failure control failure is astoundingly new for me. Who is the manufacturer of this control?

We removed the Traxoil and changed it to normal oil float systems(Sporlan)

The Traxoil gives only a signal when to low in oil level, not on to low in oil pressure (which is in my opinion far most important)

Therefore, we had installed also a Danfoss MP54 differential oil pressostat.

So we had a broken compressor due to a lack of oil where both security devices had failed (the MP54 was our own fault due to the missing cover)

Dan, I think I described in my 1st post no so well the oil pressostat. I think it is not new for you, only the (my) explanation for it was confusing.

Marc, I will try to remember to use paragraphs, but the box I'm now typing in is a little bit to small for me to type comfortable. I don't have an overview of what i've typed already.

Quote:

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Originally posted by chemi-cool
Hi Peter,
the main problem with oil is to find out WHY it went into
chemi

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I think you meant 'went out of the system.."

In a pack where different contractors service a system, it's hard to find the cause and franckly, we such a client a really don't care to mutch to find the cause.

Quote:

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Originally posted by Dan
The oil pressure safety device sensed lack of oil pressure, but the head cooling fan would not permit the heater to achieve the necessary temperature to trip the safety contacts?

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Yes, we simulated it at least 4 times with and without the cover and in presence of the technical responsable of that supermarkt chain.

All the racks for this client must now have OPSD on a separte panel.

You learn something new everyday, will keep this in mind, we have lots of racks with a similar setup.

Quote:

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Originally posted by Marc O'Brien
Peter the 1st has a lot of interesting stuff to say, I reckon I'd find even more interesting stuff in his posts if he used paragraphs.

Well, if he didn't, I'd still look out for his posts.

Nicely contrasted there, Dan.

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are you saying dan 'hasn't' any interesting stuff to say??

cheers


richard

Hi Peter,
What do you do with the oil after you change a burned out compressor?
Dont you you check acidity or change all the oil?

Chemi

When installing a new machine, almost all the oil is removed with the compressor.

Theoretically, we also need a paper of a recognized company for the destruction of the oil.

For small hermetic compressors (till +/- 1,5 HP), we pour AcidAway in the suction line and if we have enough time we install a burnout filter.

For semi-hermetic, we always install a burnout filter and pour AcidAway in the sump. After 1 week, we remove the burn-out or
remove the core for larger units.

For compressors > 5 Hp, we change the oil in the compressor once again after 2 to 3 days.

It's a long time ago we really checked the acidity of he oil.

I think we only rinsed 3 t o 4 times the system the last 10 years.

I believe the product AcidAway and after all this years, we never had problems afterwards.

Perhaps a little explanation of our self invented, simple but effective oilfilling-system: we pour the oil in a standard liquid receiver and vacuum the receiver aftwerwards via the service ports. Then connect the inlet to the discharge of the compressor (or a ***** cilinder) and the outlet to the sump (or service port on the suction line) and let the machine run (or open the cilinder). It's goin really fast this way.

hi peter,

thanks for the information.
why not use oil pump? it takes one minut to fill 15 liters and you dont need to evacuate.

if you want I will give you name and model of the pump.

chemi

If you mean a handpump, we have this. But it takes with a handpump mutch longer to pump oil in pressurised compressor sump.

I never saw an electrical pump for this.

We evacuate to be sure all moisture and air is removed.

Why we use it? A liquid receiver is very cheap and it has become a standard technique of us. I don't say it is the best technique.

Perhaps another hint: if you have not enough oilpressure, one of the reasons can be a clogged (blocked?) oilfilter in the compressor.
If there is not enough time to remove the filter or the machine has to run at least for some hours before the filter can be removed, we shut off the suction, let the machine run until atmosferic pressure, switch it off. We inject then some liquid of the receiver in the service port of the oil pump so that the oil rinses as far as possible the oil filter. The dirt is not gone - i know- but it is somewhere in the sump but the machine can at least run a while with enough oilpressure.

I know, you have to be very carefull when starting up again, and it is not a technique described in any manual, especially not in thise of the manufacturer.
But sometimes, we have to uses techniques we better not tell to our clients, our colleages and the manufacturer.

hi peter,
look here http://www.clipper-pumper.dk/smoreolieel.htm
it s a danish site but you can see the oil pump. the model I have is VISCOMAT 70 a hell of a pump.
cleaning oil filters is a standard job, more, to see if there are any metal particals on the magnet inside the plug.

hand pumps are useful up to three L.

Chemi

its an italian made pump.

chemi