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46 RTAC-SVX01F-EN
Installation - Mechanical
Water Pressure Relief Valves
CAUTION
Shell Damage!
To prevent shell damage, install pressure relief valves in the evaporator
water system.
Install a water pressure relief valve in the evaporator inlet piping between the evapo-
rator and the inlet shutoff valve, as shown in Figure 25. Water vessels with close-cou-
pled shutoff valves have a high potential for hydrostatic pressure buildup on a water
temperature increase. Refer to applicable codes for relief valve installation guidelines.
Freeze Protection
If the unit will remain operational at subfreezing ambient temperatures, the chilled
water system must be protected from freezing. Heaters are factory-installed on the
packaged unit evaporator and will help protect it from freezing in ambient tempera
-
tures down to -20°F (-29°C).
Install heat tape on all water piping, pumps, water box nozzles and other components
that may be damaged if exposed to freezing temperatures. Heat tape must be
designed for low ambient temperature applications. Heat tape selection should be
based on the lowest expected ambient temperature.
Add a non-freezing, low temperature, corrosion inhibiting, heat transfer fluid may also
be added to the chilled water system. The solution must be strong enough to provide
protection against ice formation at the lowest anticipated ambient temperature. Refer
to
Table 1 through Table 5 in the General Information section for evaporator water
storage capacities.
NOTE: Use of glycol type antifreeze reduces the cooling capacity of the unit and
must be considered in the design of the system specifications.
CAUTION
Evaporator Damage!
ALL unit chilled water pumps must be controlled by the Trane CH530 to
avoid catastrophic damage to the evaporator due to freezing. Refer to
RLC-PRB012-EN.
Low Evaporator Refrigerant Cutout and % Glycol
Recommendations
1. Solution freeze point is 4 deg F below operating point saturation temperature.
2. LRTC is 4 deg F below freeze point.
Procedure
1. Is operating condition contained within Table 9? If no see “Special” below.
2. For leaving fluid temperatures greater than 40 deg F, use settings for 40 deg F.
3. Select operating conditions from Table 9.
4. Read off recommended % glycol.
5. Go to Table 10. From the % glycol.