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6.0 Functional description
EN
6.1 General
description
The water passes from the quick coupling (a) through a water fi lter (b) into the high pressure pump (c).
The high pressure water leads through the discharge system of the pump where the safety and circulation
valve (d) is situated. Then it passes the fi rst fl ow switch (e) to the non-return valve with throttle (f), through
the second fl ow switch (g) and en ters the boiler (h). Here the water is heat ed to the required tempera-
ture. After the boiler the hot high pressure water pass es the tem per a ture sensor (i), through the outlet
quick connector (j) to the spray han dle (k) and the spray lance (l). The fuel is drawn from the fuel tank (m)
through the fuel fi lter (n) by the fuel pump (o). Now the pump leads fuel through the solenoid valve (p) to
the noz zle (q) where it is ig nit ed.
The combustion in the boiler is monitored by the fl ame sensor (w) and is supplied with air from the fan (r)
which together with the high pressure pump (c) are driven by the petrol engine (s).
6.2 High pressure pump
On the pressure side the high pressure pump features a circulation valve (d). This valve leads the water
back to the suction side of the pump when the spray handle is closed or if a nozzle is blocked. The circula-
tion valve also functions as a safety valve and has been adjusted to open approx. 25 bar above the work-
ing pressure. The valve has been adjusted and sealed from the factory.
This adjustment must NOT be
changed!
When the machine stops it is automatically devoid of pressure.
6.3 Petrol
engine
A description of the operation/maintenance instructions for the Honda engine will be found in the Honda
manual provided with the machine. Please read this before starting up. The throttle limit of the engine has
been adjusted by Nilfi sk-ALTO so that the max. number of revolutions corresponds to the max. pressure of
the pump (see section "1.2 Technical data"). The adjustment is sealed and must NOT be changed.
6.4 Burner system - control system
The burner system is surveyed and controlled by an electronic control unit which includes a thermostat,
fl ow switches to control the water fl ow and a sensor to monitor the fl ame.
The water temperature is controlled by the temperature sensor (i) which regulates the fuel supply for the
burner through the solenoid valve (p). As the burner is only allowed to operate when there is a water fl ow
in the system (i.e. when the spray handle is activated) the machine features two fl ow controls (e-g) which
con trol the fuel supply through the electronic control unit. When the fl ow in the system is interrupted, the
fl ow switch es are activated and the fuel supply will stop. When the water fl ow repeats, the fl ow switches
are re ac ti vat ed and reallow the fuel supply. Safety circuits in the electronic control unit survey that both fl ow
switch es are activated. Thus the fuel supply is interrupted when only one of the fl ow switches are activated.
When the water fl ow is repeated the control unit only allows the fuel supply if both fl ow switches have been
activated.
The fl ame sensor is a separate circuit stopping the machine if there is no fl ame in the burner in hot water
or steam mode.
It is important for the life of the fuel pump that the machine is not allowed to run in the hot water or cold
water mode with empty fuel tank. If the burner stops working unexpectedly, check the fuel level in the tank
and refi ll if necessary.
NB!
Changes of the electrical coupling of the machine are not allowed.