Prochem Legend SE AD - Manual (Page 19)

OPERATION
LEGEND SE 980059 06/19/03 3-11
This chapter of the operator’s manual divides the
unit up into systems and explains how each system
works. Before proceeding into the operation and
maintenance sections of this manual, we
recommend acquiring a basic knowledge of how this
unit functions. Read the next section of this manual
carefully and completely.
WATER PUMPING SYSTEM
See Figures 14 and 15. Cold water enters the
console through the water inlet connection located
on the lower front panel. The water flows to the
water box through a float valve, which shuts off
water flow when the water box is full.
Water then flows from the water box, through a
strainer, into the water pump where it is pressurized.
This pressurized water is pumped to the pressure
regulator manifold where the pressure regulator
provides and maintains the desired pressure setting.
The pressure regulator manifold includes a nitrogen
charged accumulator which helps reduce pressure
pulsation’s. In addition, the manifold also contains a
low-pressure switch and a high-pressure switch.
These switches will shut the unit down if the water
pressure drops below 50 PSI or exceeds 1200 PSI.
If the tool valve is closed, water flows from the
pressure regulator through the vacuum exhaust
radiator-type heat exchanger, where heat is
transferred from the vacuum pump exhaust to the
water.
The heated water then returns to the water box. If
the temperature in the water box exceeds
180
°
F, a temperature relief valve will open and bleed
a small amount of hot water into the waste tank,
allowing cool water to flow into the water box.
When the tool valve is open, water flow is from the
pressure regulator to the engine exhaust heat
exchanger, where the water is super-heated by
engine exhaust.
A bypass manifold, located next to the water box,
constantly bleeds a small amount of hot water from
the engine exhaust heat exchanger outlet to the
water box.
Next, the hot water flows through the check valve
manifold which contains a check valve and
Y-strainer. This is where chemical injection occurs.
The hot solution then flows through the solution
outlet manifold to the cleaning tool.
Temperature is adjusted primarily using the
thermostatic temperature control. This control opens
a solenoid valve if the water exceeds the
temperature setting. When open, this valve allows
hot water to be drawn into the waste tank. The
temperature sensor for this control is located in the
thermostat manifold en route to the solution outlet.
In addition, a heat bypass valve on the lower front
panel lowers the solution temperature manually with
a knob adjustment. When open, this valve allows
hot water to be drawn into the waste tank.
An additional temperature sensor on the engine
exhaust heat exchanger outlet will shut down the
engine if the water temperature exceeds 285
°
F. If
this occurs, consult the “Trouble-shooting” section of
this manual to determine the cause of overheating
before restarting your unit.