Thrush DSHE Series - Manual (Page 21)

Thrush Co.
Manual #9636-0555
4.5 Operation
The Thrush HOT-PAK is an indirect fired semi-instantaneous water heater. It utilizes a
shell and tube heat exchanger and industry standard controls to provide a constant
source of hot water for an open system. Figures 4-5, 4-6 and 4-7 show the Hot-Pak in
various stages of the operation sequence. A standard Hot-Pak is shown, actual
configuration may vary.
To protect the tube bundle from damage, the unit must be filled with water before
allowing steam to enter.
With the unit full of water, and control panel set to the “ON” position, it will begin to
circulate the water inside the shell. Tubes and baffles are omitted for clarity. (Figure 4-5)
Figure 4-5 Operating Sequence (Circulated Water Flow)
With the temperature setting on the control valve set to the specified value, the control
valve will allow steam to enter the tube bundle. (Figure 4-6). As steam flows through the
tube bundle, the temperature of the steam will drop causing it to condense. The steam
condensate will exit through the head of the unit to a properly sized steam trap. The
steam trap should be piped to an adequate drain. For proper operation, the steam
condensate must be removed.