BEPOWEREQUIPMENT COMMERCIAL HW255E1CNG, User Manual

Page: 11 / 28

11
FLOW SWITCH
The flow switch prevents the burner from being
turned on if there is insufficient water. Proper
water flow causes the magnetic core to be
pushed up, closing the reed contact. This con-
tact is interlocked with the gas control valve.
UNLOADER VALVE
The Unloader Valve allows all of the water
delivered by the pump to return to the pump
suction side. If the trigger gun is closed or
“OFF”, the Unloader Valve goes into the
“bypass mode” and the pump runs without
pressure. However,
the pump may be severely
damaged, due to excessive overheating, if left
running in the “bypass mode” or “gun-off”
situation for more than 6 minutes.
SAFETY RELIEF VALVE
The Relief Valve prevents the machine from
being subjected to abnormally high pressures.
If this situation occurs, the valve will blow off
relieving the pressure in the coil. This valve may
also operate if the unloader is adjusted too
high.
PRESSURE SWITCH
The Pressure Switch ensures that there is
pressure, and therefore there is water flow at
the head of the pump. This control does not
operate at less than 300 psi. Therefore if the
pump is on “bypass mode”, the burner will not
operate. Also, if the Unloader is turned back
less than 300 psi in the steam mode, the burner
will not operate. The effect of this switch is
very similar to that of the flow switch.
THERMOSTAT
The built-in thermostat stops the unit from
overheating. Maximum temperature of the unit
is 230 ° F. (110 ° C) Above this temperature, the
burner stops automatically.
HIGH LIMIT SWITCH
The High Limit Switch is a thermostat which
operates at a higher temperature than the
built-in thermostat, about 300
°
F. (150
°
C.) This
switch is not adjustable and will only operate
when other controls fail to keep the water
temperature within the normal operating range.
Unlike the other burner control switches, this
switch cuts the power to the whole gas valve,
not just the gas solenoid.
COMBINATION AUTOMATIC GAS VALVE
The gas valve incorporates a manual shut-off
valve, a gas regulator, the pilot control and a
timed automatic shut-off. The functions of the
manual shut-off and regulator are simple. The
manual shut-off closes the gas inlet so that
no gas can enter the burner. The regulator
regulates the flow of gas to keep it at constant
pressure. The pilot control is a pilot control
valve and thermocouple sensor. The pilot
valve can be opened to light the pilot burner.
When lit, the burner flame is directed to a
thermocouple sensor. The sensor heats up from
the flame and allows the pilot valve to stay
open permitting automatic operation of the
burner. If the pilot goes out, the thermocouple
will cool down and the control will shut-off the
gas supply. The pilot must then be manually
relit.
SAFETY COMPONENTS