OPERATION
CHILLER-IOM-2004-E
35
3.
UNIT OPERATION: REFRIGERATION CIRCUIT
3.1.
Tandem and Trios scroll assemblies
With tandem and trios assemblies the oil balancing is achieved through the use of a large two phase line tube
It is IMPERATIVE that this tube is perfectly level during operation to ensure proper oil balancing between the
two crankcases
It is also IMPERATIVE for the compressor to be mounted on a rigid base frame as there is no flexibility in the
oil equalizing line. The whole assembly can then be mounted on silencers.
The oil equalizing Line is fitted with a sight glass which can be used to check the oil level in the compressor assembly. It is mandatory to
stop both compressors to get a good reading of the oil level in the crankcase of the compressors.
There can be two types of tandem assemblies:
• EVEN TANDEM when both compressors are the same models
• UNEVEN TANDEM when compressors are different models
In the case of uneven tandem assemblies a restrictor is inserted in the suction of one of the two compressors.
The purpose of this restrictor is to equalize the suction pressure in order to ensure a better oil return to both compressors. Contact LENNOX
after sales offices for additional information.
WARNING: THE UNIT WITH UNEVEN TANDEM CAN NOT OPERATE WITHOUT A RESTRICTOR.
3.2.
Copeland scroll discharge temperature protection
If the oil in the compressor gets too hot it will start to deteriorate and loose its ability to lubricate, and will eventually cause a compressor
failure. LENNOX compressors are sometimes fitted with a specially designed sensor in the hottest part of the compression cycle, just
above the discharge port of the scroll sets. This sensor is connected to the solid-state protection module in the terminal box. If the
temperature rises above a pre-set value, the compressor will be shut down for 30 minutes before restarting the compressor.
Oil equalizing line
must be level
Gas
Oil
!
!
