Unit Network : Installation - Emerson Copeland EazyCool OMQ-56-Nxx-TWD Series Application Manuallines

3.6

2 Unit Network : installation

1 Suction line
2 Liquid line
3 Liquid line equalizarion line (between receivers)
4 Liquid line pressure equalization line (between receivers)
5 Oil distribution lines with Schraeder valves
Table 9: Connection Sizes
In a 2-unit network, the tubing arrangement for low temperature as well as medium
temperature is similar.
Pipe position at rear of the unit is identical for single compressor condensing units.
IMPORTANT
For low temperature network systems, Copeland recommends to insulate the complete
liquid outlet line to the evaporator expansion valve in order to optimise the sub-cooling
effect.
3.6.1 2 Unit Network: Master/Slave selection recommendations
As compressor-starting priority is based on balancing running hours, Copeland
recommends the compressor used in the Master unit to be bigger and/or equal in
capacity as in Slave units, in order to achieve identical capacity modulation steps.
Therefore a network could be composed of either only single compressor units or two-
compressor units.
Network configuration could be composed also by a single compressor unit (as master,
which will start first always) and a two-compressor unit as slave.
NOTE: Configuration with a two compressor unit as master and a single compressor unit
as slave is not recommended as modulation steps would not be all the time equal.
3.6.2 2 Unit network: Possible Master/Slave configurations
Slave
Master
Suction line
C6.1.4/0305/E
Condensing Unit For Refrigeration Networks
Connection
Liquid line
20
ø (inch)
1 3/8
5/8
1 1/8
5/8
1/4
Master unit is base load:
Master Q > Slave Q
0 0
(*) Suction & liquid line to evaporator(s)
Part no: 3136433