PUMP AS

The gear set draws oil from the tank through the built-in fi lter and transfers it to the
valve that regulates the oil pressure to the nozzle line. All oil that does not go through
the nozzle line will be dumped through the valve back to the return line in two pipe
installation or, if it is a one-pipe installation, back to suction port in the gear set. In
that case, the by-pass plug must be removed from the return port, and the return
port sealed by steel plug and washer.

The solenoid valve of the AS pump is of the “normally opened” type.
When the solenoid valve is non-activated, the by-pass channel between the pressure
and return sides of the valve is open. No pressure will then be built up to open the
valve; it does not matter which speed the gear set has.
When the solenoid is activated, this by-pass channel is closed and because of the
full speed of the gear set, the pressure necessary to open the valve will be built up
very rapidly, which gives a very sharp cut-on function.

Cut-off
When the burner stops, the solenoid opens the by-pass at the same moment, which
drains all the oil down to the return, and the nozzle valve closes immediately. This
gives a very sharp cut-off function.
The cut-on and cut-off can be actuated regardless of motor speed and have an
extremely fast response.
When the solenoid is not activated, the torque requirement is low up to full motor
speed.

Bleed
Bleeding in two pipe operation is automatic, but it may be accelerated by opening
a pressure port.
In one pipe operation, a pressure port must be opened to bleed the system.