Revs per minute
Most pumps will prime (start to lift water) at 2500rpm
2 Low Pressure Gauge
Measured in bars
(14.7psi=1bar)
Reads from 0 to 20 bars and usual max. pressure given to a large hose is 7 bars or 105 psi
3 Compound gauge
(Pressure in bars or vacuum being achieved from 0 to -1bar)
4 High Pressure Gauge
Pressure being delivered to first aid / first attack reels) Measured in bars and usually about 15 to 20 bars.
5 Pump Engaged Light
Power take off
6 On / Off valve 
Control water going to individual first aid / hose reels.
7 Crossover valve.
From low pressure to high pressure stage. Allows water to go to high pressure stage where the pressure is then increased about 3/4 times and then fed to the first aid reels.
8 Delivery Outlet
Main hose snaps in here to deliver water from the pump to the fire.
9 Eye of the Pump
Water goes in here from a hydrant or river etc.
10 Pump casing
Centrifugal pump inside.
11 Tank fill inlet.
Fills the 1800 litre on board water tank.
12 Pump throttle.
Controls the speed of the pump.
13 Tank to pump valve lever.
Allows water to flow from the on board tank to the pump.
14 Foam Concentration adjustment.
Used in conjunction with the on board foam tank and foam producing system
15 Flowmeter
Digital flowmeter for each delivery showing how much water per litre minute is being delivered.

The Godiva WT Series two-stage pump is a dual pressure pump.  It can be used for high volume, low pressure (LP) output or for low volume, high pressure (HP) output, or both simultaneously.  When the pump is running, LP flow is always available, but HP is available only if the HP selector valve is in the closed position.  The HP outlet is separate from the LP outlets and is mounted on the top rear of the pump.  It is recommended that if HP is not required, then the change over valve is left in the open position, as this will reduce engine and transmission loads and noise.

A pressure relief valve is fitted which allows a small amount of water to circulate back to the LP stage to prevent the pump from developing excessive pressure, should it be operated at HP against closed HP discharge valves.

The pump is generally driven in a clockwise direction viewed from the drive end.  The pump may also be specified configured to rotate 'in a counterclockwise direction.  The pump drive shaft, which runs on angular contact and roller bearings in an oil bath, is of stainless steel.  Shaft sealing of the pump is by a special Godiva mechanical seal face, which ensures efficiency and long life without adjustment.  The electronic tachometer sender is mounted adjacent to the drive flange.

Priming of the pump is achieved automatically by means of a pair of positive displacement piston primers mounted on either side of the bearing housing.  These primers begin to operate as soon as the pump drive shaft begins to rotate, driven by an eccentric bearing on the pump shaft.  Air within the pump will be expelled and as long as the suction connections have been made and the hose end submerged, the pump will prime and the pistons will disengage by 1.5 bar.  The pump should be primed at any speed between 1000-2700 rpm.  The pump speed should not be increased further until the primers have disengaged and the pump is primed.

An optional alternative priming system - the Godiva water ring primer - is available in place of the piston primer system.  With the water ring primer, when the pump is started, the primer shaft is driven by its fibre driving wheel, which contacts the pulley on the pump drive shaft and is lifted off by a disengaging cylinder as the pump is primed and pressure builds up in the pump.  An alternative to friction pulley drive is belt-drive through an electromagnetic clutch.  When the pump is primed and pressure builds up, a pressure switch turns off the clutch drive.

Non-return valves are built into both the piston and water ring priming systems to prevent air flowing back through the primers, thus "breaking the prime".

As the pump is reduced to idling and the pressure within the pump decreases, the pistons will once again re-engage to act as a pump and discharge any water remaining in the pump.

HP delivery is from a connection mounted on the top rear side of the pump which is threaded internally to 1 ¼" BSP or rearwards via a flange.