TM 10-4610-232-12
(3) Media filter, Freeze up during deployment should be avoided to assure continued availability.
(a) If freezing cannot be avoided, drain and air purge to avoid solidly freezing the media and internals.
(b) If drained only and allowed to freeze, thawing will require similar time and heat as required for the RO
elements (para. 2-31c(1)(d)).
(c) If drained and purged before freezing, the filter can be returned to service.
(4) NBC Filter. The NBC filter should be treated the same as the media filter.
(5) Chemical Systems. The chemical tubing will freeze if not purged. Damage is unlikely, however, thawing time
will delay availability. Protection is provided by air purging according to long term shutdown procedures.
(6) Raw Water Pump. When deployed for a cold weather mission, the pump is covered with a cover and the heat
lamp is installed. The heat lamp keeps the pump casing warm when the pump is not operating. While the pump is
operating, the water flow will prevent freezing. When securing the ROWPU, or when the diesel generator fails, the
pump must be drained within 15 minutes.
(7) Distribution Pump. When deployed for a cold weather mission, the pump is covered with a cover and the heat
lamp is installed. The heat lamp keeps the pump casing warm when the pump is not operating. While the pump is
operating, the water flow will prevent freezing. When securing the ROWPU, or when the diesel generator fails, the
pump must be drained within 15 minutes.
(8) Piping. Flowing water will not easily freeze, so there is little danger of freeze up while the ROWPU is running.
When the ROWPU is shut down during cold weather, however, water in the pipes can freeze. Expansion during
freezing will damage piping. Therefore, the ROWPU must be drained when the temperature in the ROWPU cannot be
maintained above 32°F (0°C).
(9) Lay-Flat Hoses. When the ROWPU is running there is little danger of hoses freezing. The hoses will not freeze
rapidly, Ice may build up, however, at the end connectors and begin to restrict the water flow. Covering with 12 inches
of dirt or snow will reduce this problem. Ice will begin to form in the hoses within a short time after shutdown at -25°F
(-32°C). If the ROWPU is to be shut down longer than 15 minutes, hoses must be disconnected at all joints and fully
drained. Start-up is simplified if lay-flat hoses are also rolled and placed within the ROWPU until needed.
(10) Product Tanks. Ice formation is slowed by inserting an open dispensing nozzle into two tanks and the product
hose into the third tank. The distribution pump is kept operating. The tanks will still slowly freeze from the outside walls
until sufficient ice is formed to prevent further freezing. Ice will also form at the metal connectors. This can be
minimized by berming dirt or snow over the connections. The best approach is to erect a tent (not provided with
ROWPU) over the tanks and maintain a temperature around 20°F (-7°C).
d. Choosing a Water Source. If the water source is frozen, a hole through the ice must be cut. The water temperature
will be different at different depths. Usually the warmest water will be found near the bottom. Sometimes the warmest
water will be between 6 and 12 inches below the ice. Seawater freezes at 28°F (-2°C). Care must be taken to obtain
water over 32°F (0°C), since the product water may freeze. Shallow water bays should be avoided since the water
below the ice will be highly concentrated with dissolved solids. Try to choose a water site where the equipment can be
set up with the minimum amount of hoses. The more that are used increases the likelihood of freezing problems.
e. Assembly and Preparation for Use in Cold Weather (Figure 2-69). Cold weather set-up is a little different from
normal set-up. Procedures are rearranged to bring the diesel generator set on line as early as possible to power the
space heaters. One heater is run continuously during transport drawing power from the diesel generator batteries.
More than one hour without the diesel running may excessively discharge the batteries and may lead to battery freeze
up.
NOTE
Keep doors closed whenever possible during unpacking and set-up.
(1) Set trailer (para. 2-14b).
(2) Establish electrical power.
(a) Ready diesel generator (para. 2-14e).
(b) Check ground cables for tightness at both ends.
(c) Connect utility cable from tractor 24 VDC connector to the generator 24 VDC slave connection. Keep tractor
engine running to provide boost.
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