Water Pressure Relief Valves; Freeze Protection - Trane RTAA-70 Installation & Maintenance Manual

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Installation — Mechanical

Water Pressure Relief Valves

Install a water pressure relief valve in the evaporator inlet piping between the
evaporator and the inlet shutoff valve, as shown in
with close-coupled 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, following the steps
listed below:
1. Heat tape is factory-installed on the packaged unit evaporator and will
protect it from freezing in ambient temperatures down to -20 F .
2. Install heat tape on all water piping, pumps, 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.
3. Add a non-freezing, low temperature, corrosion inhibiting, heat transfer
fluid 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
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.
Table 1 for evaporator water storage
Figure 15. Water vessels
RTAA-SVX01A-EN