Vilter 440 - High Oil Consumption.

[DoubleZout]

I have a Vilter 440 that consumes massive amounts of oil ( up to 2-3 gal.per day). This problem appears intermittantly although this compressor has always consumed oil at a faster rate than others we have in service. All operating pressures and temps appear normal. A top end rebuild has not improved anything. Oil returning from seperator is loaded with coked oil particles at times causing problems with return float. Obviously the oil must be burning to some degree. Wonder if anyone has any suggestions? Would appreciate any feedback.

[US Iceman]

up to 2-3 per day


2-3 what? liters, pints, quarts, gallons?????

Does the compressor start and stop frequently?

[DoubleZout]

Sorry...It was gallons. I corrected it in my posting. The compressor runs constantly with little variation in load. Only gets shut down for oil drain every 3 days (normally).

[US Iceman]

Only gets shut down for oil drain every 3 days (normally).


Let me see if I have this right. You are putting 2-3 gallons of oil into the compressor every day and then shutting it down every 3 days (or so) to drain oil out of it.

Why are you draining oil out of the compressor every 3 days or so?

[Josip]

Hi, DoubleZout :)

Welcome to RE forums...


Sorry...It was gallons. I corrected it in my posting. The compressor runs constantly with little variation in load. Only gets shut down for oil drain every 3 days (normally).

:confused:.....from part of oil separator with coalescent filter in or....


Best regards, Josip :)

[Gary]

Compressors don't consume oil. If the oil level is low, ask yourself, "Where did the oil go to?". It is out in the system somewhere... and the problem is that it is not coming back to the compressor.

[DoubleZout]

Thanks for the feedback so far. I need to clarify the nature of this problem a bit better. The problem is that this compressor, which would normally go through a crankcase of oil in a weeks time ( without oil returning through a seperator and float valve ) now goes through the same volume in as little as 2 hrs. The rate of consumption does vary but is never more than a day without having to add a full crankcase of oil. As a result, oil must be drained from the recievers a few times a day, hopefully draining as much oil out as is lost through the discharge side of the compressor. The excess oil ending up in the top end of the compressor becomes carbonized ( due to high discharge temp? ) and ends up back at the oil return float valve. These carbon particles cause problems with the operation of the oil return float valve thereby limiting return oil to the crankcase. This sets up a bit of a vicious cycle. I am puzzled as to how this volume of oil gets through the compressor from crankcase to discharge. The compressor top end was rebuilt with no improvement. The oil operated unloaders were suspected also, but could not find a problem there either. Hope this info may ring some bells. I appreciate the input.

[US Iceman]

What is the discharge superheat on this particular compressor?

[Gary]

What type of oil separator do you have?

[Franzfernando]

liquid flooding and a poor oil seperator maybe too small?

[NH3LVR]

I am puzzled as to how this volume of oil gets through the compressor from crankcase to discharge.
The answer to that one is simple. All compressors pump oil. It sounds as if yours does so to an excessive degree though.
(I am assuming NH3)
The first thing I would do is to drain and flush the oil seperator. Then install a filter/drier canister with a standard 46 cu/inch core in the return line. I also like a solonoid and thermostat so it will only return oil when the oil seperator is hot.
You may have another problem, but you have to be able to return the oil. There are many factors which affect the amount of oil loss when the oil return fails.
An example; a couple of years ago a customers 12 Cylinder Vilter (two stage) had a float fail. I do not remember at the moment but I think it was on the highside (8 Cylinders). This machine lost almost 5 gallons per day, for three months. We had to drain oil for weeks.

[Crewcutrick]

The only way you could be pumping this much oil, Double - is through the unloading system. I assume that your unloaders are oil pressure actuated (as opposed to discharge gas actuated as are found in some situations).

You either have a crack, deformity, or most likely broken head gasket that is allowing oil under pressure to migrate from the unloading cylinder into the compression cylinder where it gets pumped out.

The easiest way to confirm is to remove the head covers on unloading sections. The suspect heads will be very apparent, lots of oil, discharge valves cleaned of carbon (if this is an ammonia machine), and a broken gasket ligament between unloading cylinder and one of the two compression cylinders. It may also be due to the last guy that rebuilt - if he was too agressive in his gasket scraping of either block or head, he may have left behind some defect that is conducting oil into the compression cylinder.

Good Luck!!

R

[Mark Selby]

The greater the compression ratio the more oil you will send to the sep...In all post above I dont see what your suction and disch readings are. How is this comp being used???High or low stage??? If low stage you got real issues but if your running it as a high stage 5-15# suction and 145 and up disch this will make the mach run hot and carry over a lot of oil, also running unloaded will make you sling oil but (not cook it). If more info is given I can give a better responce.