Pressure Tech MF-414 Series Service manual

1
THE MF-414 SERIES
Operating and Service Manual
Series includes all variants of MF-414
Issue C
Dec 2018

2
TABLE OF CONTENTS
1. Description.............................................................................................................................3
2. Installation .............................................................................................................................3
3. Operation ...............................................................................................................................4
4. Special Conditions for Safe Use .............................................................................................5
5. Hazardous Location Usage.....................................................................................................5
6. Servicing and Maintenance....................................................................................................5
6.1. Servicing the MF-414G............................................................................................6
6.1.1. Accessing the Main Valve Assembly........................................................6
6.1.2. Accessing the Sensor Assembly ...............................................................7
6.1.3. Figure 1 –Sectional View of the MF-414G ..............................................8
6.2. Servicing the MF-414H............................................................................................9
6.2.1. Accessing the Main Valve Assembly........................................................9
6.2.2. Accessing the Sensor Assembly .............................................................10
6.2.3. Figure 2 –Sectional View of the MF-414H ............................................11
7. Technical Data......................................................................................................................12
8. Warranty Statement ............................................................................................................12

3
1. Description
The MF-414 is a ‘medium flow’ piston sensed pressure reducing regulator, which incorporates
a balanced main valve to provide stable control under varying inlet pressures. The regulator
has the option of a PEEK seat for gas service, or TX 2000 ceramic for hydraulic service.
Both designs have a segregated captured vent to allow pressure reduction of the outlet
pressure through a ¼” NPT port on the side of the regulator body.
An internal sensing line protects the sensing mechanism from potential damage as the main
valve opens.
2. Installation
Before system start-up, it is recommended that all systems be pressure tested, leak tested
and purged with an inert gas such as nitrogen.
Prior to placing into service ensure that the regulator is in the fully closed position, with the
adjusting mechanism turned completely anti-clockwise.
Check the model number reference to ensure that the pressure range complies with the
installation requirements.
Visually inspect the regulator for any signs of damage or contamination. If any foreign
materials are present and cannot be removed from the regulator, or if the threads on the
regulator appear to be damaged, please contact the office immediately to arrange for the
regulator to be returned for service.
The Inlet and Outlet ports are clearly marked. Select the correct size and type of connection
fittings for these ports which are indicated in the regulators part number. Both British
Standard Pipe (BSPP) ‘B’and National Pipe Thread (NPT) ‘N’options are available on this
regulator. Use the correct dowty or bonded seal for BSPP connections, self centering seals are
recommended. For NPT threads, ensure that PTFE tape is applied correctly to the fittings,
applying two overlapping layers in the direction of the thread, taking care that the tape does
not come into contact with the first thread.
Any gauge ports on the regulator will be 1/4” NPT unless otherwise stated. If any gauge port
is not required, ensure that the port is plugged prior to installation.
The media supplied to the regulator must be clean. Contamination can damage the seat which
may cause the regulator to fail. Filtration suited to the application is recommended upstream
of the regulator.
Should further assistance or information be required in relation to installation of any Pressure
Tech regulator please contact the office, giving reference to the regulators part number
and/or serial number.

4
3. Operation
Turning the hand wheel (or T-Bar) clockwise compresses the load spring, which in turn opens
the main valve, and allows the inlet pressure to pass through the orifice until the outlet
pressure is equivalent to the loading forces set by the compressed spring.
Self venting regulators can reduce the outlet pressure by turning the hand wheel anti-
clockwise, which will allow the excess pressure to vent through the vent port located on the
side of the regulator body. This port should not be plugged or blocked at any time.
Note: Turning the hand wheel anti-clockwise (with pressure on the outlet) should be refrained
on non-venting regulators. Pressure should be reduced in this case by venting downstream of
the regulator, and turning the hand wheel simultaneously anti-clockwise.
The MF-414 series may be offered with pressure limiting, pressure locking or pre-set pressure
options:
Pressure limited regulators are fitted with locknuts on the adjusting mechanism in order to
limit the maximum allowable downstream pressure. Regulators fitted with pressure limiting
locknuts will state the limited pressure on the regulator label and this will also be indicated in
the part number.
Pressure locking regulators are fitted with a locking cap which may be set (when specified) to
pre-determined requirements. It is secured in place by three M5 grub screws which lock
against the bonnet of the regulator creating an anti-tamper device to ensure the pressure
cannot be adjusted accidentally.
Pre-set pressure regulators are adjusted (factory set) to specified customer requirements
within a given pressure range.
Both pressure locking and pre-set pressure regulators will be fully adjustable through a given
pressure range and the maximum allowable working pressures will be indicated on the
regulator label and in the part number.
*Note - A table is available on request defining allowable tolerances for set points within a
given pressure range.

5
4. Special Conditions for Safe Use
Sudden dynamic high-pressure inlet pressures should be avoided, and preferably be gradually
increased to protect against damage to the regulator.
5. Hazardous Location Usage
This equipment has not been manufactured specifically for use in potentially explosive
atmospheres and as such an ignition hazard assessment has not been carried out on this
product. If the user should wish to use this product in such an environment where there may
be a potentially explosive atmosphere then it is the responsibility of the user to conduct an
ignition hazard assessment against 99/92/EC.
6. Servicing and Maintenance
Servicing and maintenance work on the MF-414 regulators should only be performed after
fully reading and understanding the Operating and Servicing Manual. Due to the typical
nature of the gases the regulator can be used with, the operator should not endanger
himself/herself or others by working on this regulator without prior knowledge on the Health
and Safety concerns relating to handling of technical gases. Any uncertainty should be
clarified with Pressure Tech before working on the regulator.
Pressure Tech Ltd recommends the use of Krytox GPL 205 during servicing.
Prior to commencing service, please ensure that:
-The equipment has been de-pressurised
-The load spring has been de-compressed by turning the adjusting mechanism fully
anti-clockwise
-Applications involving toxic, flammable or corrosive media have been fully purged
To ensure the best possible results from servicing, when re-assembling the regulator and any
assemblies within it, ensure that all areas of the components and the regulator body are
cleaned and free from contaminants which may result in failure of the regulator.

6
6.1. Servicing the MF-414G
*Note: fig 1 should be used as a reference for the following set of instructions
6.1.1. Accessing the Main Valve Assembly
*The top works and sensor assembly must first be removed to access the main valve
assembly. Before continuing follow the steps ‘i. – vi.’ shown in - ‘6.1.2. Accessing the Sensor
Assembly’.
To access the Main Valve Assembly:
i. Unscrew the body nut (2) from the body (1) of the regulator to access the lower
section of the main valve assembly.
ii. Remove the Valve Spring (3).
iii. Secure the upper section of the main valve (10) with a 10mm socket and use a
screwdriver to turn the seat nut (4) anti-clockwise.
iv. Remove the seat nut, ‘O’ rings and soft seat (4, 6, 9 and 8) from the lower main
valve assembly.
v. The main valve pin (10) should be removed through the top of the regulator to
avoid damaging the ‘O’ ring (11) located on it.
vi. Remove the hard seat (7) from the body of the regulator (1) by turning it anti-
clockwise with a 19mm socket.
vii. Insert a new hard seat (7) into the regulator body after carefully positioning the
12mm x 1mm ‘O’ ring (9) into the body.
viii. Place two drops of Loctite thread lock 638 (or equivalent) on the M6 thread on the
main valve pin (10)
ix. Replace the ‘O’ ring (11) and back-up ring (12) on the main valve (10) and place
the main valve into position through the top of the regulator body with the hex
section facing upwards.
x. Turn the regulator body upside down so that the lower section of the main valve
is visible and place a new soft seat (8) onto the main valve stem.
xi. Replace the BS-610 ‘O’ ring (6) and place into the seat nut (4).
xii. Screw the seat nut (4) on to the main valve (10) and tighten both parts together
using a 10mm socket and a screwdriver.
xiii. Place the valve spring (3) into the bottom nut (2) and screw into the regulator body
(1). Tighten the bottom nut to 30Nm.
To ensure that the main valve assembly has been correctly and effectively installed it may be
required to perform the appropriate seat leak test as per ANSI/FCI 70-2.

7
6.1.2. Accessing the Sensor Assembly
The loading mechanism and vent seat for the MF-414 can be accessed from the top of the
regulator. Ensure the spring is de-compressed by rotating the hand wheel fully anti-clockwise
and follow the instructions below:
i. Remove the securing grub screw (23) from the regulator body (1).
ii. Unscrew the pan screw (33) and remove the name plate (32) from the hand wheel
(30).
iii. Unscrew the locknut (31) and remove the hand wheel (30) from the adjusting
screw (28).
iv. With the regulator secured up-right in a vice, remove the bonnet (29) by using a
torque wrench or equivalent with 47mm open end.
v. Un-screw and lift the top works from the assembly, inclusive of the bonnet (29),
load spring (24), adjusting mechanism (25, 26, 27 & 28) and lower spring rest (21)
from the body.
vi. The sensor assembly (13, 14, 15 & 16) can be removed from the body by using an
M5 bolt (supplied with kit) and pliers.
vii. The vent seat (14) can be accessed by removing the sensor (15) from the sensor
holder (16) and gripping the sensor firmly in a vice with the vent seat nut (13)
facing upwards.
viii. The vent seat nut (13) can be removed using a pin spanner or equivalent and the
vent seat (14) can then be removed from the sensor (15).
ix. Inspect the vent seat (14) for damage and replace if necessary.
x. Replace all ‘O’ rings (17, 18 & 19) located on the sensor (15) and sensor holder (16)
prior to reassembly, ensuring adequate lubrication is used.
xi. After reassembling the sensor and holder, place the assembly into the regulator
body (1) ensuring that it is firmly in place.
xii. Remove the M5 screw from the sensor holder if used.
xiii. Screw the top works onto the regulator body and using a torque wrench, tighten
to 120Nm.
xiv. Tighten the securing grub screw (23) against the bonnet (29).
xv. The hand wheel (30) can now be secured on to the adjusting screw (28) using the
locknut (31).
xvi. The name plate (32) can then be secured using the pan screw (33).
It is recommended that all parts in the repair kits are used. Any defect parts removed during
the service should be disposed of.
Replacement ‘O’ rings should be lubricated with suitable non-hydrocarbon grease such as
Krytox GPL 205.

8
6.1.3. Figure 1 –Sectional View of the MF-414G
© Copyright of Pressure Tech Ltd
* ALL DIMENSIONS IN MILLIMETERS, UNLESS OTHERWISE STATED.
PARTS LIST
DESCRIPTION
PART NUMBER
ITEM
BODY 3/4" NPT
PT-305-MF-N-SS-06N
1
BOTTOM BODY NUTPT-305-MF-0042
MAIN VALVE SPRINGPT-305-MF-0053
SEAL NUT
PT-300-MF-005 -002
4
O' RING STD
OR-0270-25
5
O' RING STD
OR-BS6106
SEAT
PT-305-MF-008
7
PEEK SEATPT-C-002-019-0018
O' RING STD
OR-0120-109
MAIN VALVE
PT-305-MF-001-00310
O' RING STD
OR-BS4518-0066-24
11
BACK UPPT-C-08212
VENT SEAT NUTPT-C-091-00113
VENT SEATPT-C-029
14
25mm SENSORPT-C-142-002
15
25mm SENSOR HOLDERPT-C-141-00216
O' RING STD
OR-BS4518-0416-24
17
O' RING STD
OR-BS4518-0246-2418
O' RING STD
OR-BS4518-0456-2419
SLIDE RING
PT-C-03820
SPRING REST - DOMEPT-C-095-00121
O' RING STD
OR-0350-2022
GRUB SCREW
FIT-M3X523
SPRINGR40X89 SPRING24
ADJUSTING NUTPT-C-04525
SCREW
PT-C-04626
BEARINGBEAR-5110327
ADJUSTING SCREWPT-C-043-00428
BONNETPT-C-040-00129
LARGE NYLON HAND WHEELPT-C-048-00130
LOCK NUTPT-C-13231
NAME PLATE
PT-C-04932
SCREW
FIT-M3X8
33
Ø74
Ø75
110
33
277
58
2
15
3
4
6
7
8
9
10
11
12 13
15
14
17
18
16
19
18
21
22
23
24
25
26
20
29
28
27
30
31
32
33

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6.2. Servicing the MF-414H
*Note: fig 2 should be used as a reference for the following set of instructions
6.2.1. Accessing the Main Valve Assembly
*The top works and sensor assembly must first be removed to access the main valve
assembly. Before continuing follow the steps ‘i. – iv.’ shown in - ‘6.2.2. Accessing the Sensor
Assembly’.
To access the Main Valve Assembly:
i. Unscrew the body nut (2) from the body (1) of the regulator to access the lower
section of the main valve assembly.
ii. Remove the Valve Spring (3).
iii. Secure the upper section of the main valve (10) with a 10mm socket and use a
screwdriver to turn the seat nut (4) anti-clockwise.
iv. Remove the seat nut, ‘O’ rings and ceramic seat (4, 6, 9 and 8) from the lower main
valve assembly.
v. The main valve pin (10) should be removed through the top of the regulator to
avoid damaging the ‘O’ ring (11) located on it.
vi. Remove the hard seat (7) from the body of the regulator (1) by turning it anti-
clockwise with a 19mm socket.
vii. Insert a new hard seat (7) into the regulator body after carefully positioning the
12mm x 1mm ‘O’ ring (9) into the body.
viii. Place two drops of Loctite thread lock 638 (or equivalent) on the M6 thread on the
main valve pin (10)
ix. Replace the ‘O’ ring (11) and back-up ring (12) on the main valve (10) and place
the main valve into position through the top of the regulator body with the hex
section facing upwards.
x. Turn the regulator body upside down so that the lower section of the main valve
is visible and place a new ceramic seat (8) onto the main valve stem.
xi. Replace the BS-610 ‘O’ ring (6) and place into the seat nut (4).
xii. Screw the seat nut (4) on to the main valve (10) and tighten both parts together
using a 10mm socket and a screwdriver.
xiii. Place the valve spring (3) into the bottom nut (2) and screw into the regulator body
(1). Tighten the bottom nut to 30Nm.
To ensure that the main valve assembly has been correctly and effectively installed it may be
required to perform the appropriate seat leak test as per ANSI/FCI 70-2.

10
6.2.2. Accessing the Sensor Assembly
The loading mechanism and vent seat for the MF-414 can be accessed from the top of the
regulator. Ensure the spring is de-compressed by rotating the hand wheel fully anti-clockwise
and follow the instructions below:
i. Remove the T-Bar (30, 31) by unscrewing one side whilst firmly gripping the other.
ii. With the regulator secured up-right in a vice, remove the bonnet (29) by using a
torque wrench or equivalent with 47mm open end.
iii. Un-screw and lift the top works from the assembly, inclusive of the bonnet (29),
load spring (24), adjusting mechanism (25, 26, 27 & 28) and lower spring rest (21)
from the body.
iv. The sensor assembly (13, 14, 15 & 16) can be removed from the body by using an
M5 bolt (supplied with kit) and pliers.
v. The vent seat (14) can be accessed by removing the sensor (15) from the sensor
holder (16) and gripping the sensor firmly in a vice with the vent seat nut (13)
facing upwards.
vi. The vent seat nut (13) can be removed using a pin spanner or equivalent and the
vent seat (14) can then be removed from the sensor (15).
vii. Inspect the vent seat (14) for damage and replace if necessary.
viii. Replace all ‘O’ rings (17, 18 & 19) located on the sensor (15) and sensor holder (16)
prior to reassembly, ensuring adequate lubrication is used.
ix. After reassembling the sensor and holder, place the assembly into the regulator
body (1) ensuring that it is firmly in place.
x. Remove the M5 screw from the sensor holder if used.
xi. Screw the top works onto the regulator body and using a torque wrench, tighten
to 120Nm.
xii. Tighten the securing grub screw (23) against the bonnet (29).
xiii. Place the T-Bar piece with the male thread (31) through the hole on the adjusting
screw and tighten the second T-Bar piece (30) against it.
It is recommended that all parts in the repair kits are used. Any defect parts removed during
the service should be disposed of.
Replacement ‘O’ rings should be lubricated with suitable non-hydrocarbon grease such as
Krytox GPL 205.

11
6.2.3. Figure 2 –Sectional View of the MF-414H
© Copyright of Pressure Tech Ltd
* ALL DIMENSIONS IN MILLIMETERS, UNLESS OTHERWISE STATED.
33
110
263
◼74
150
PARTS LIST
DESCRIPTION
PART NUMBERITEM
BODY 3/4" NPT
PT-305-MF-N-SS-06N
1
BOTTOM BODY NUTPT-305-MF-0042
MAIN VALVE SPRING
PT-305-MF-0053
SEAL NUTPT-300-MF-005 -002
4
O' RING STD
OR-0270-25
5
O' RING STD
OR-BS6106
SEAT HOLDERPT-305-MF-006
7
CERAMIC SEAT
PT-C-002-0278
O' RING STD
OR-0120-109
MAIN VALVE PIN CERAMIC DESIGNPT-305-MF-001-00210
O' RING STD
OR-BS4518-0066-24
11
BACK UPPT-C-08212
VENT SEAT NUT
PT-C-091-00113
VENT SEATPT-C-029
14
12mm SENSORPT-C-087-002
15
12mm SENSOR HOLDERPT-C-085-00216
O' RING STD
OR-BS4518-0416-24
17
O' RING STD
OR-0116-2418
O' RING STD
OR-BS4518-0456-2419
SLIDE RINGPT-C-03720
SPRING REST - DOMEPT-C-095-001 ISSD21
O' RING STD
OR-0350-2022
GRUB SCREW
FIT-M3X523
517 KG SPRINGR40X89 SPRING24
ADJUSTING NUTPT-C-04525
SCREW
PT-C-04626
BEARING 420SS51103-SS27
ADJUSTING SCREW
PT-C-043-00128
BONNETPT-C-040-00129
T BAR HANDLE
PT-C-10730
T BAR HANDLE
PT-C-10831
2
1
5
58
3
8
7
4
6
9
10
11
12
14
18
19
20
22
23
13
15
17
16
18
21
24
29
28
25
26
27
30 31

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7. Technical Data
Fluid Media: All gases and liquids compatible with materials of
construction
Max Inlet Pressure: 414 bar
Outlet Pressure Range: 5-414 bar
Operating Temperature: -20°C to +80°C
Materials: Body and Trim: 316 SS
Seat Gas: PEEK®,
Seat Hydraulic: Ceramic
Flow Capacity (Cv): 2
Leakage: Hydraulic: Zero drops of water at max inlet
Gas: Bubble tight
8. Warranty Statement
Pressure Tech Ltd guarantee all products correspond with their specification at the time of
delivery and, with exception to wear and tear, wilful damage, negligence, and abnormal
working conditions, will be free from defects for a period of 12 months from date of delivery.