Trane IntelliPak SCRF 25, Installation, Operation And Maintenance Manual

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SCXF-SVX01Q-EN 39
minimum of 1/2" for each 10' of horizontal run, away
from the unit. Be sure to install the condensate drain
“P” trap drain plug. Before starting the unit, fill the trap
with water to prevent negative pressure in the fan
section from impeding condensate flow.To facilitate
drain pipe cleaning, install plugged tees in place of 90°
elbows.
General Waterside Recommendations
for Cooling Towers
Cooling tower control affects the unit cycle rates.
Condenser water temperature swings from 10-15°F
may cause excessive compressor, water valve, and unit
cycling. Be sure to set the tower controls to minimize
compressor/unit cycling.
Waterside Piping Arrangements
Install a condenser water pump between the cooling
tower (either open or closed) and the self-contained
unit. Lay out the remainder of the system condenser
piping in reverse returns. This helps balance the
system by equalizing the length of supply and return
pipes. Multi-story buildings may use a direct return
system with balancing valves at each floor.
Install the supply riser and its return in close proximity.
Furnish both with permanent thermometers to check
the waterside balance during startup and routine
maintenance checks.
Also, include strainers at each pump inlet and unit.
Install drain valves at the riser’s base to allow drainage
points for system flushing during startup and routine
maintenance. For condenser draining and header
removal, include a shutoff/balancing valve on the
entering and leaving waterside pipes, drain tees, and
unions of each unit.
N No otte e:: Unit does not have floor drains.
Figure 23. Condenser water piping components for
cooling tower system
Water Temperature Requirements
Do not allow the entering water temperature to go
below 54°F (12.2°C) on units with constant water flow
(basic piping).This will cause the compressors to shut
down and the mechanical cooling function will lockout.
However, the economizer (if enabled) will continue to
function. The compressors will reset when the entering
water temperature reaches 58°F (15°C).
Units with variable water flow (intermediate piping)
have a modulating condensing pressure control valve
that allows compressor operation down to entering
water temperatures of 35°F (2°C).
For more information on constant and variable water
flow, see the Sequence of Operation section of this
manual.
N No otte e:: Units with a waterside economizer can be set
from the human interface panel for variable or
constant water flow.
Water Piping Verification
• Make return and supply water connections to the
unit and/or waterside economizer piping package
with recommended valves and piping components.
• Install unions to allow waterside maintenance.
• Install cooling tower and standby pumps.
• Treat water to prevent algae, slime, and corrosion.
• Prevent refrigerant piping from rubbing against
other objects.
Installating the Hydronic Coil
Steam and Hot Water Coil
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N No otte e:: Hydronic coil options are available only on 20-80
ton units and can be field or factory mounted.
1. Position the coil box behind the unit with open side
facing the unit inlet.
2. An envelope containing the gasket and mounting
screws to attach the coil to the unit ships in the
bottom of the unit. Install the pressure sensitive
gasket to the unit side of the vertical flange on the
coil box in two places.
3. Before attaching the coil box, connect the coil duct
static pressure tube. This must be done before the
coil box is bolted to the unit. If the unit connection
does not have a static pressure tube, then no
connection is required.
4. Apply edge protector to the flange on unit. Remove
knockout on the unit filter cover and install the
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