12-21. OPERATION IN EXTREME COLD - cont.
When the ROWPU is shut down during cold weather (temperature falls below 32°F (0°C), remove the R.O.
elements (para. 3-4), and cartridge filters (para. 3-5). Store the elements indoors or in a tent where the
temperature is above freezing and allow them to dry.
To prevent injury to personnel and damage to equipment, make sure water is drained toward lower
ground at least 25 yards downstream from raw water inlet.
When the equipment is shut down during cold weather (temperature falls below 32°F (0°C), perform the
following steps to ensure water is drained from ROWPU piping, filters, pumps and connections.
To prevent damage to the equipment, all hoses must be disconnected from pumps, and all pumps,
hoses, pipes and tanks drained quickly. All drain and vent valves must be opened and all
equipment inspected to assure complete drainage.
Drain ROWPU pipes, filters and connections (para 2-17 b.).
Drain chemical feed pump (para 2-17 c.).
Drain booster pump (para 2-17 i.).
Drain R.O. pump (para 2-17j.).
Drain distribution pump and raw water pumps No. 1 and No. 2:
Disconnect inlet and outlet hoses from pumps.
Tip pumps toward each connection to permit drainage.
Open drain and vent valves on raw water pumps No. 1 and No. 2 (figure 2-51).
Operate pumps (39-41, figure 2-5) for less than 5 second intervals until all water is out.
Shut off pumps.
Drain backwash pump:
Disconnect backwash suction hose at backwash pump.
Open draincock on bottom of backwash pump (figure 2-28). Drain pump and backwash strainer.
Close draincock on pump.