9
QB Oil Fired Water Heaters • Rev. 4/13/2016
OPERATING CHARACTERISTICS
MAXIMUM WORKING PRESSURE
The water heater coils are designed to operate safely at specific working pressures (see
SPECIFICATIONS for the water pressure of your model). Each water heater is equipped with a
safety pressure relief valve (unloader) which prevents operation above this pressure. If the high
pressure system requires a lower relieving pressure for pump and motor protection, then the
unloader/bypass valve on the pumping unit should be adjusted to desired pressure rating.
HIGH LIMIT TEMPERATURE CONTROL
The water heater is equipped with a “high limit control” thermostat present at 220 F. It shuts down
the burner in the event of excessive outlet temperature caused by insufficient water flow through the
heater coil. This control can be adjusted to desired temperature up to but not exceeding 220 F.
PRESSURE SWITCH
A pressure switch is installed on the high pressure pump to prevent burner operation in the absence
of water flow. When heater is used with shutoff gun pumping systems, the pressure switch controls
the burner in conjunction with operation of the trigger gun.
FLOW SWITCH
A flow switch is installed on the outlet of the high pressure pump and will shut off the pump and
motor in the absence of water flow as well as turning it back on when flow is detected (by
squeezing the wand trigger).
BURNER
The oil burner is a conventional type that is factory preset for most efficient operation
SAFETY RELIEF VALVE
WARNING: The safety relief valve on this unit has been factory set and is not to be adjusted.
Tampering with relief valve may cause personal injury or equipment damage and will void
the manufacturer warranty.
