Installation, Operation and Maintenance Manual
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3.3.3
Total Equivalent Line Length Calculation
1. The “equivalent line length” is the sum of the straight
length portions of the refrigerant line plus losses in
equivalent length from 45° and 90° bends and fittings. Add the total straight (lineal) length of tubing to the
equivalent length of fittings, elbows and bends to get total equivalent length.
Total Equivalent Line Length = Length(
Horizontal)
+ Length(
Vertical)
+ Losses from bends + Losses from fittings
2. The total equivalent line length is then used to determine the refrigerant line sizes from the recommended
line sizing charts.
Post Piping Installation
After interconnecting piping is installed, the piping system must be cleaned. If solvents/cleaning solutions are used,
ensure they are completely flushed from the piping before connecting it to the unit. Failure to do so will result in
equipment problems.
Water/Glycol Cooling Unit Piping
Water/Glycol-cooled units are factory-charged and tested. Field-supplied and field-installed piping is required from
the unit to building water or tower water sources or the fluid cooler (i.e., dry cooler) and pump package. Pipe size
will depend on length of run and the maximum water flow required. The Engineer of Record or Design Engineer is
responsible to determine piping sizes based on the installation site conditions.
The required field installed fluid cooler pipe sizes may or may not be the same as the connection sizes on the fluid
cooler. Refer to the Fluid Cooler Installation, Operation and Maintenance manual for connection sizing). The pipe
size will depend on the length of pipe and the calculated pressure drop of peripheral components.
Shutoff valves, field provided, should be installed within a few feet of the inlet and outlet connections of the
evaporator to allow the unit to be isolated for service. There should be a means of draining the unit for service.
Field supplied drain/fill valves should be located at the lowest point on the connected piping.
Water/glycol cooled units are normally shipped with plate/fin heat exchangers as standard equipment. A strainer
is shipped loose (factory provided) and is to be field installed in the supply line with shut-off valves before and after
the strainer. The strainers and water/glycol piping must be cleaned on a periodic basis. If the unit is shipped with
optional a co-axial or shell and tube condenser, strainers are not required nor shipped with the unit.
All water pipes have a temporary cap installed on the end of the pipe for pressure testing the fluid system. These
temporary caps must be removed before installing the piping to the units. Use a tube cutter for smaller pipes and
a reciprocating saw with a metal cutting blade for larger pipe sizes or if there is a clearance problem. All connections
need to be cleaned before connections are brazed together.
NOTICE
One of the most common problems in a water/glycol system is the
presence of air in the condenser water loop. Air vents must be installed in
various locations the piping system to purge the air.
Water/Glycol cooled system piping may include a centrifugal pump (or pumps for redundancy) available from Data
Aire as an option. Union(s), shutoff valves, and check valve(s) are field provided. A flow switch can be provided by
Data Aire as an option.
Pumps must be primed before operating per the pump manufacturer’s guidelines.