The Preso Model PFA Fire Pump System is FM-approved and features the
Preso Ellipse primary flow sensor. The Preso patented elliptical design
outperforms and provides greater accuracy than traditional differential
pressure flow measurement devices. This differential pressure flow meter
is designed with a series of ports facing the upstream velocity pressures, as
well as flow sensing ports strategically located ahead of the trailing edge
flow separation.
The multi-ported, self-averaging flow element consists of an elliptical shape
with two independent flow sensing chambers. The impact velocity sensing
holes (high pressure) are located along the leading edge and the true
static sensing holes (low pressure) are on the exterior probe side. Model
PFA Fire Pump System comes with instrument shutoff valves with provisions to
accept a direct indicating meter.
SPECIFICATIONS
User Manual
True static
sensing holes
Impact velocity
sensing holes
Figure 1: PFA pressure sensing holes
ApplicationsLiquids
Pipe Sizes2…16 in. (5…406.4 mm)
Pressure400 psi (2758 kPa) maximum
TemperatureGage180° F (80° C) maximum
PFA Velocity Sensor250° F (121° C) maximum
Accuracy±1.75% of reading
Turndown Ratio17:1 with no vacuum effect
Standard ComponentsY-type head, brass
Compression fitting;
2…5 in., brass
6…16 in., CS with SS ferrule
CS 3000 lb weld fitting, ASTM A105
316/316L SS Ellipse sensor
Instrument valves (2 per sensor), 1/4" male SAE flare brass ball
Polycarbonate ID tag with wire
Direct reading gage, brass body, 270° arc
Reynolds NumberGreater than 75,000 maintains most accurate flow measurements
Less than 75,000 consult factory for estimated results
Double SupportDouble support required for the following Systems
OTE:NPipe must remain full at all times during measurements.
Figure 2: Horizontal pipe installation
MEDIDOR DE FLUJO
DEBITMETER S
FLOW METER S
APPROVED
M
F
L
H
FIELD
WELD
FLOW
FLOW
FIELD
WELD
FLOW METER S
DEBITMETER S
MEDIDOR DE FLUJO
H
L
F
APPROVED
M
LIQUID
OTE:NPipe must remain full at all times during measurements.
Figure 3: Vertical pipe installation
Page 4 April 2014
User Manual
INSTALLATION INSTRUCTIONS, SINGLE SUPPORT
1. Choose the proper location to install the PFA Fire Pump System Ellipse using AGA/ASME standards (or equivalent). See
“Preso Ellipse Location Instructions” on page 7.
2. Grind the surface of the pipe where the PFA Fire Pump System Ellipse is to be inserted to provide a clean area for welding.
3. Weld the supplied weld-o-let to the pipe using standard codes for your application (1/16" weld gap recommended).
Takecare to protect the threads during the welding process.
4. Drill a hole through the pipe wall according to Table 2.
5. Deburr the hole just drilled, especially on the inside of the pipe.
Pipe SizeModel / SensorWeld ConnectorDrill Bit
2…5 in.PFA (1/2")1/2"5/8"
6…12 in.PFA (7/8")1"1-1/8"
14…16 in.PFA (1-1/4")1-1/4"1-3/8"
Table 2: Single support drill bit size
6. Install the supplied compression tting by threading it into the weld-o-let manually. Then with a wrench, tighten the
tting another 1-1/4 turns, taking care not to tighten the compression nut.
7. Install the instrument valves at the PFA Fire Pump System Ellipse head connections. Make sure the valves are FULLY
CLOSED to prevent them from leaking during startup.
8. Insert the PFA Fire Pump System Ellipse through the compression tting. See Figure 4. Carefully push the sensor by hand
further into the pipe until it reaches the opposite wall.
9. While holding the PFA Fire Pump System Ellipse in its fully inserted position, align the arrow located on the sensor head
with the direction of ow. See Figure 5.
10. Thoroughly tighten the compression nut in order to prevent leakage. After tightening the compression nut manually, turn
it another 1-1/4 turns with a wrench.
INSTALLATION INSTRUCTIONS, DOUBLE SUPPORT
1. Follow steps 1 through 7 in “Installation Instructions, Single Support”. At 180° from and on the same plane as the previously
drilled hole, grind the surface of the pipe to provide a clean area for welding. Drill a hole and deburr, especially on the
inside of the pipe. The hole used for the double support should be sized according to Table 3.
2. Weld the double support weld-o-let making sure that it is centered with the drilled hole (1/16" weld gap recommended).
3. Install the PFA Fire Pump System Ellipse sensor through the two holes. Make sure that the double support pin passes
through the guide ring. See Figure 6.
4. Align the arrow located on the sensor head in the direction of ow as in step 9, “Installation Instructions, Single Support”.
5. Ensure that the PFA Fire Pump System Ellipse is in the correct orientation and spans the inside of the pipe. Tighten the
compression nut. After tightening the compression nut manually, tighten it 1-1/4 turns more using a wrench.
6. Install the plug into the end of the double support weld-o-let. Tighten the plug to prevent leakage.
Nut
Insert
Body
Figure 4: Compression fitting assembly
Thread nut loosely
onto body of the
compression tting
Install insert
as shown
Threaded portion
to be installed
into weld tting
on pipe
Page 5 April 2014
Ellipse® Pitot Tube Meter, PFA Fire Pump System
FLOW
Pipe SizeModel / SensorWeld ConnectorDrill Bit
2"…5"PFA (1/2")1/8"3/8"
6"…12"PFA (7/8")1/2"1/2"
14"…16"PFA (1-1/4")1"7/8"
L
H
M
F
APPROVED
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJ O
FIELD
WELD
Figure 5: Sensor alignment
Table 3: Double support drill bit size
L
H
Figure 6: Double support pin
GAGE MOUNTING
1. The FGE gage can be line, bracket or panel mounted.
2. For liquid applications, install the FGE below the
PFA Fire Pump System in a level position. See Figure 7.
OTE:NIf recommended mounting is not possible, make sure the
gage is vented periodically.
Ellipse Sensor
Double Support Pin
Guide Ring
FLOW
H
2000
1500
1000
M
F
APPROVED
L
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
VENT
VALVES
3000
2500
GPM
M
F
3500
APPROVED
4000
PFA-XXX
X inch
250 SWP
X/XX
S/N AXXXXXXX
BYPASS
VALVE
Figure 7: Recommended installation
Page 6 April 2014
User Manual
LOCATION INSTRUCTIONS
Straight pipe requirements: Accuracy is affected by the piping configurations due to the disturbances of the flow profile. A
fully developed symmetrical flow profile is achieved with the minimum upstream and downstream recommended lengths.
DISTANCES ARE EXPRESSED IN
NUMBER OF NOMINAL PIPE DIAMETERS
THROTTLED VALVE OR REGULATOR
27
FLOW
REGULATORY OR
PARTIALLY CLOSED
VALVE
6
2
5
FLOW
STRAIGHTENING VANE
4
9
FLOW
10
6
4
2
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
4
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
PRESO
PRESO
9
10
4
2
FLOW
6
4
411
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
PRESO
PRESO
4
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
4
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
PRESO
PRESO
TWO ELBOWS IN DIFFERENT PLANES
24
10
55
2
FLOW
FLOW
4
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
4
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
STRAIGHTENING VANE
TWO ELBOWS IN THE SAME PLANECHANGE IN PIPE SIZE
113
FLOW
9
45
2
FLOW
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
3
FLOW METERS
DEBITMETERS
MEDIDOR DE FLUJO
PRESO
PRESO
PRESO
PRESO
F
APPROVED
Discharge
Optional to
Pump Inlet
Supply
M
FLOW
FLOW
STRAIGHTENING VANESTRAIGHTENING VANE
PRESO FIRE PUMP SYSTEM
Throttle Valve
Air Vent
Fire Pump
3000
2500
GPM
M
F
3500
2000
APPROVED
1500
1000
4000
PFA-XXX
X inch
250 SWP
X/XX
S/N AXXXXXXX
PRESO
PFA
Pipe Diameters From Valve
Valve
Figure 8: Location instructions
System Bypass Valve
Flow
73
Flow
STRAIGHTENING VANE
F
APPROVED
Throttle Valve
M
Page 7 April 2014
GAGE INSTALLATION
1. The connecting tubing between the PFA Fire Pump System and the gage should be as short as possible and should slope
down a minimum of 1 inch per foot.
2. Secure and support the tubing to prevent sagging and/or vibration.
3. Make sure the head heights are even.
4. Run a bleed line from the gage vent valves to a pan or drain.
GAGE OPERATION
1. Identify Hi and Lo pressure inlets on the gage.
2. Make sure the bypass valve (blue) is OPEN!
GAGE MAY BE DAMAGED IF INITIALLY PRESSURIZED WITH THE BYPASS VALVE CLOSED.
3. Connect the gage to the corresponding Hi and Lo pressure taps of the PFA Fire Pump System (via three-valve manifold, if
being used).
4. Open the Hi and Lo instrument valves on the PFA Fire Pump System .
5. Alternately open the Hi and Lo vent valves to purge the lines.
6. When venting is complete, close the bypass valve to begin taking reading.