TM 11-6780-225-35
ES82A.
Onequarter ampere fuses for each of the
2-9.
Water System
exhaust fans are located on the control panel.
(fig. 22)
(2) Drying with unheated air from space heater
The function of the water system (TM 11678022512)
UH684. If the SUMMERWINTER damper control is set
is to supply hot and cold water to, and remove waste
in the SUMMER position, a damper will prevent the flow
water from the processing sink. The water system has
of air into the heating ductwork.
Setting the drying
five modes of operation as follows: water source under
cabinet heat control to the open position, and setting S9
pressure (a below), water source from a lake or stream
on the control panel to the FAN position will cause
(b below), darkroom water tank water source (c below),
unheated air to be drawn in through the fresh air intake
snow as a water source (d below), and water drainage (e
and forced upward into the film and print drying cabinets
below).
Five indicators are used to monitor the
by the UH684. The exhaust fans may be operated to
functions of the water system and are described in f
accelerate drying as described in (1) above.
below. For functioning of the processing unit refer to TM
(3) Drying with heated air from space heater
11674028635.
UH684. For this mode of operation, the drying cabinet
a. Water Source Under Pressure. Pressurized
heat control, and the SUMMERWINTER damper control
water at a minimum of 20 psi (pounds per square inch)
are set as described in (2) above.
and a maximum of 90 psi is brought into the ES82A
S1l on the control panel is set to the DRYER position,
through the water input connection, and flows through
which allows the space heater thermostat S1 to monitor
the strainer to remove any large foreign particles. With
the operation of the UIT684.
The maximum
valves D6 (drain) and S1 (supply) closed, and S2 open,
temperature setting for Si is 105F (41C).
When
the water flows into the pressure regulator. Waterflow
switches S6, S7, and S8 (as required) are set to the
into the water pump is prevented by the pressure relief
AUTO position, the film drying cabinet thermostat S3 and
valve (adjacent to S2) and the check valve.
In the
the print drying cabinet thermostats S4 and S5 are
pressure regulator, if required, the water is reduced to a
allowed to monitor the operation of exhaust fans B1, B2,
maximum of 40 psi. The water then flows into the inlet
and B3.
pressure indicator. From the inlet pressure indicator the
Lamps DS1, DS2, and DS3 provide visual indication of
water flows through a 2micron filter to remove any
the operation of the exhaust fans.
The maximum
foreign particles, through the flow indicator, and into the
temperature setting for S1, S2, and S3 is 2F (1C) less
outlet pressure indicator.
With valves D2 and S9
than the temperature set on S1.
closed, the water is diverted into two paths from the
When S9 on the control panel is set to the HEATER
outlet pressure indicator. On one path, the water flows
position, heated air at a constant temperature will be
into the 50gallon water tank, causing the water tank to
forced upward through the film and print drying cabinets
act as a buffer for the water system. With valves D4,
by the UH-68-4. The heated air is drawn past the film
S4, and S5 closed, the other path branches the
and/or prints and vented to the outside by the exhaust
waterflow in one direction to cold water valve S7, and in
fans, causing rapid drying by evaporation.
the other direction to the bottom of the 3.5-gallon water
heater.
A 4.5kw heating element combined with a
2-8.
Water Heater
preset thermostat will, if required, heat the water to
(fig. 31)
150F (65.5C). The heated water then flows from the
When ON-OFF water heater switch S1 is set to the on
top of the water heater to hot water valve S6. If the
position, normally closed solid state relay K2 allows
pressure in the water heater exceeds 90 psi, the excess
current flow to energize normally open relay K1,
water is drained into the floor manifold. By manipulating
switching power to 4.5kw heating element R1 and
valves S4 and S5, hot and cold water may be mixed and
illuminating pilot lamp DS1. Thermostate S2 will open
directed to pass through present flow control valve F1 at
when the water temperature reaches 150F (65.5C),
1/2 gpm, as replenishment water for the processing unit.
deenergizing relay K2 causing relay K1 to deenergize
b. Water Source From Lake or Stream. When
and remove power from R1 and DS1.
Relay K2 is
operating with a lake or stream as a water source, the
grounded to the water heater tank creating a current path
float prevents mud and sediment from entering the water
through the water to a probe immersed in the water. If
system. A screen prevents other debris from entering.
the water in the tank falls below the level of the probe,
With this mode of operation, the water pump must first
the current path is broken and relay K2 is deenergized.
be
primed.
In
the
prim
Relay K1 is then deenergized and power is removed
from R1 and DS1.
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