Trane oil seperator

[El Padre]

Greetings,

I have got an oil flow problem on a Trane RTAC 170, the oil charge is correct, transducer ok, oil filter ok, no blockage in oil return line from the evaporator (which is not flooded), the chiller does however run on low load and is standard efficiency, which I believe indicates that it was not designed to run at low ambient conditions, the other circuit however runs fine under the same conditions.

Has anyone ever come across a faulty oil seperator? I assume that there are baffles inside which could be broken, there is very little oil in the seperator and no sign of a leak, the oil is obviously in the evaporator, discharge line etc.

Any suggestions on proving that the seperator is the cause? I have suggested removing the charge and the oil again and then recharging the oil and refrigerant and monitoring how long it takes for the oil to leave the seperator, how efficient should the oil seperator be given that the system is both oversized for the application and being used on the edge of its design parameters.

A quick question regarding Techview, should the service literature be available when connected to the CH530? As it was'nt. Also in Techview it showed the status of the evaportor oil return solenoid on the functional circuit, whilst it did not show this on the faulty circuit ( all blank, as if there was'nt one ) the coil was however energised when I checked.

Hopefully it makes some sort of sense!!

Cheers

[serviceman]

readings would have machine operation, solenoid valve operates the oil return, dehydrator filter is clean?

[Gingerair]

Ahoy there El Padre !!

Hope someone can help with this problem, or even explain the operating structure that activates the solenoid valve in the line from the the bottom of the evap to the underside of the comp.

Is this just an oil return line or is it also used in a way similar to liquid injection ?? If so, does it work off discharge temp ??

For some reason the oil is being carried over through the oil sep & therefore we presume must be in the evap..

If anyone has had a similar problem we would be interested to hear from you..

Taa all..

[serviceman]

solenoid valve oil return to the compressor operates only in operation, it is intermittent

[serviceman]

solenoid valve oil return to the compressor operates only in operation, not intermittent

[serviceman]

Oil Recovery

Despite the high efficiency of the oil
separators, a small percentage of oil will
get past them, move through the
condenser, and eventually end up in the
evaporator. This oil must be recovered
and returned to the oil sump
(separators).
Incorporated in the oil system is an oil
management line which helps to return
accumulating oil in the evaporator back
to the compressors. The oil
management line consists of an isolation
valve on the bottom of the evaporator,
an oil strainer, and a solenoid valve just
before the oil enters the bottom of the
compressor. The oil then combines with
oil injected into the compressor and
returns to the oil separators.

[serviceman]

The oil separator consists of a vertical
cylinder surrounding an exit
passageway. Once oil is injected into the
compressor rotors, it mixes with
compressed refrigerant vapor and is
discharged directly into the oil
separators. As the refrigerant-and-oil
mixture is discharged into this
passageway, the oil is forced outward by
centrifugal force, collects on the walls of
the cylinder and drains to the bottom of
the oil separator. The bottom of the oil
separator acts as an oil sump.
Oil that collects in the oil separator is at
condensing pressure during compressor
operation; therefore, oil is constantly
moving to lower pressure areas. As the
oil leaves the oil separator, it passes
through the oil filter and master control
valve. Oil flow then follows two distinct
paths, each performing a separate
function: 1) bearing lubrication and
cooling and 2) rotor oil injection.
If the compressors stop for any reason,
the master control valve closes. This
isolates the oil charge in the separators
during

“off” periods.
To ensure proper lubrication and
minimize refrigerant condensation in the
compressor and oil separator, a heater is
mounted in the compressor and oil
sump. A signal from the Tracer® Chiller
Controls energizes this heater during the
compressor-off cycle to maintain proper
oil temperature. The heater element is
continuously energized and does not
cycle on temperature.

[El Padre]

Ciao Gingerair & Serviceman,

Thanks for your input, could prove to be an interesting one!

Cheers

[JHdlinc]

Had oil return problem on my RTWD 80 the oil pump silenoid was bad. This might be a good place to start. There is also a check valve in-line on the oil return. Hope this helps.

[El Padre]

Thanks JH,

No oil pump on this one, have also checked the oil return line for a blockage, do you know if the oil return solenoid is controlled by discharge superheat?

Cheers

[JHdlinc]

Once oil is injected into the
compressor rotors, it mixes with
compressed refrigerant vapor

Oil is injected there isn't a motorized pump the pump consist of two solenoids that use the refrigerant pressure to inject the oil back to rotor and bearings.

[centrecipew]

There is an internal oil pressure relief valve, behind the internal oil filter. Thers have been occasions where these have had to be changed. The oil return solenoid valve-under the compressor is always energised whilst the compressor is running, the auxillary is on the delta contactor 30 sec delay to energise. Good luck

[serviceman]

7U4 MODULE CONTROLS THE SOLENOID VALVE AND OIL RETURN VALVE identified it as 73L4

[El Padre]

Thanks Gents,

When/if I get the order to investigate further I shall let you know what I find.

Centreipaw, I was aware of the oil flow control valve, my initial thoughts were that if this valve was at fault the oil would back up in the seperator.

Cheers