Johnson Controls PENN P70 Series User manual

Master Catalog 125
Pressure Controls Section P
Product/Technical Bulletin
Issue Date 0900
© 2000 Johnson Controls, Inc. 1
Code No. LIT-125453 www.johnsoncontrols.com
The P70, P72, and P170 controls for low pressure
applications are designed primarily for low pressure
cut-out control, pump-down control, and capacity
control on commercial refrigeration and air
conditioning applications.
These controls are available in several pressure
ranges and are compatible with most common
refrigerants. They may also be used on other
non-corrosive fluid applications. Ammonia compatible
models are also available.
Controls also are available in several different
electrical ratings and switch configurations. The
P72 models provide direct control of 208-240 volt
single-phase motors up to 3 hp, and 208-220 volt
3-phase motors up to 5 horsepower.
Figure 1: P70AB-12 MICRO-SETTM Low Pressure
Control
Features and Benefits
❑All Steel Case and Cover Built to provide long lasting, rugged protection
for internal components
❑“Sight-Set” Calibrated
Pressure Adjustment
Displays a visible pressure scale, fully
adjustable through the range without
removing the cover (on NEMA 1 enclosure
models)
❑MICRO-SET™ Differential
Option
Allows for precise control on critical low
pressure applications
❑Manual Reset Lockout
Option
Provides “trip-free” low pressure lockout that
cannot be overridden or reset until pressure
returns to specified level
❑Limited Knob Adjustment
Option
Restricts control adjustment ranges and
deters tampering and over-adjustment
P70, P72, and P170 Controls for
Low Pressure Applications

2 P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin
Application
P70, P72, and P170 controls for low pressure
applications are designed primarily to provide low-side
pressure control on commercial refrigeration and air
conditioning applications.
IMPORTANT: Except for those models listed as
Refrigeration Pressure Limiting
Controls, the P70, P72, and
P170 Series controls for low
pressure applications are
intended to control equipment
under normal operating
conditions. Where failure or
malfunction of the P70, P72, and
P170 pressure controls could
lead to an abnormal operating
condition that could cause
personal injury or damage to the
equipment or other property,
other devices (limit or safety
controls) or systems (alarm or
supervisory systems) intended to
warn of, or protect against, failure
or malfunction of the P70, P72,
and P170 pressure controls must
be incorporated into and
maintained as part of the control
system.
•P70A and P170A models with Single-Pole
Single-Throw (SPST) Open-low switch action are
the most popular models, and are typically used
for low pressure cut-out and pump-down control.
•P70 and P170 models are also available with
SPST Open-high switch action, and are typically
used for capacity control. Models with Single-Pole
Double-Throw (SPDT) or 4-wire, 2-circuit switch
action allow users to install alarm devices or other
control circuits.
•P72 models have a Double-Pole Single-Throw
(DPST) switch with load-carrying contacts that can
provide direct control of 208-240 V single-phase
motors up to 3 hp, and 208-220 V 3-phase motors
up to 5 hp. Refer to Table 8.
These controls are available in several pressure
ranges and are compatible with most common
refrigerants. They may also be used on air, water, and
other non-corrosive fluid applications. Ammonia
compatible models are also available.
The MICRO-SET option provides fine adjustment of
the differential setting for precision pressure control of
critical low pressure applications.
Some models are available with Limited Knob
Adjustment, which restricts adjustment of the
pressure settings and deters overadjustment or
tampering. See Limited Knob Adjustment.
!
CAUTION: Equipment Damage Hazard.
Ammonia is very corrosive to
copper and brass components.
On ammonia applications, only
ammonia-compatible control
models and pressure
connections must be used. The
pressure control must be
mounted separately from the
electrical cabinet and all
electrical piping sealed to
prevent ammonia from migrating
to electrical components.
The Manual Reset Lockout mechanism does not
allow the pressure control to automatically reset after
the control has cut out, providing shutdown capability
for unmonitored equipment. See Manual Reset
Operation.
NEMA 1 enclosures are standard on most models.
NEMA 3R enclosures are also available.
Operation
A pressure-actuated bellows on the control is
connected to a pressure tap on the controlled
equipment by a capillary or a field-installed hose
(except ammonia models). The bellows responds to
equipment pressure changes and operates a
snap-action electrical switch.

P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin 3
Dimensions
Two Mounting Holes
10-32 UNF-2B Thread
5/16
(9)
4
3-1/16
(77)
1-5/16
(34)
1/16
15/16
(24)
2-1/16
(52) 1-1/4
(32)
3/16
(5)
3/16
(5) Diameter
3-1/4
(83)
13/16
(20)
2-15/16
(74)
1-11/16
(43)
1-3/4
(44)
Capillary or
Connector
as Specified
3-1/4
(83)
5/16
(8)
1
(25)
1-1/8
(29)
1-7/8
(48)
5/16
(8)
3/8 X3/16
(5)
Diameter
Mounting Hole
7/8
(22) Conduit Hole
Mounting Hole
3/16
(5)
Diameter
(1/2 in. 3/4 in. Trade Size) or
1-1/8
(28)
or
Figure 2: Dimensions for Low Pressure Controls with NEMA 1 Enclosure, in. (mm)
4-1/16
(103)
4-1/16
(103)
5/8
(16)
5/8
(16)
(79)
2-15/16
(74)
(70)
3/16
(5)
1/2
(13)
(25)
2-11/16
(68)
3/8
(10)
1-1/4
(32)
1-3/4
(44)
7/16
(11)
1-9/16
1/2
(13)
3/4-NPSM
Threaded
Rigid Conduit
Connector
Four Mounting Holes 5/16
(8) Diameter
Figure 3: Dimensions for Low Pressure Controls with NEMA 3R Enclosure, in. (mm)
Note: These dimensions are nominal and are subject to accepted manufacturing tolerances and application variables.

4 P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin
Mounting
Mount the control in an accessible position, where the
control and pressure connection line will not be subject
to damage.
!
CAUTION: Equipment Damage Hazard.
Mount the pressure control
upright and level. Position the
pressure connection line to
allow drainage away from
control bellows. Pressure tap
points must be located on the
top side of the refrigerant lines.
This reduces the possibility of
oil, liquids, or sediment
accumulating in the pressure
connection line or control
bellows, which could cause
control malfunction.
Controls with NEMA 1 enclosures may be mounted on
flat, horizontal or vertical surfaces.
Use two screws or bolts through the two outer holes
on the back of the control case when mounting control
directly to a flat vertical surface.
Use the two inner holes with the Universal Mounting
Bracket (and screws supplied) when mounting the
control to a flat horizontal surface.
IMPORTANT: Use only the mounting screws
provided with the Universal
Mounting Bracket to avoid
damaging internal components.
Do not warp control case when
mounting control to uneven
surface.
Controls with NEMA 3R enclosures are designed to be
mounted in a level, upright position with the sensing
element and conduit connection facing down. All
gaskets must be in place. Mounting NEMA 3R
enclosures in any position other than upright and level
may trap water in the enclosure and submerge internal
control components.
Use mounting screws
provided. Longer screws
may damage control.
Mounting Holes for
Flat Vertical Surfaces
Universal Mounting
Bracket
(Part No. 271-51)
Mount bracket to
horizontal surface.
Figure 4: Mounting the P70, P72, and P170 Low
Pressure Control with NEMA 1 Enclosure
Pressure Connections
P70, P72, and P170 low pressure controls are
connected to the controlled equipment by a capillary or
flexible hose (except ammonia models). Controls are
available with a variety of pressure connection styles.
See Figure 11 for pressure connection styles.
Follow these guidelines when installing pressure
connection lines.
IMPORTANT: If these controls are installed on
equipment that contain
hazardous or regulated
materials, such as refrigerants or
lubricants, the installer and user
should observe all regulations
governing the handling and
containment of those materials.
Avoid Sharp Bends in the Capillary Tube
Sharp bends can weaken or kink capillary tubes, which
may result in leaks or restrictions.
Allow for Slack in the Capillary Tube
Leaving a little slack in the capillary tube helps
dampen mechanical vibration that can weaken or
damage capillary tubes.
Coil and Secure Excess Capillary Tubing
Carefully loop any excess capillary tubing into smooth,
circular coils (approximately 3 in. diameter). Securely
fasten the coiled tubing.

P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin 5
Avoid Contact between the Capillary Tubing and
Sharp or Abrasive Objects
Vibration of sharp or abrasive objects in contact with
capillary tubes can result in leaks.
Do Not Overtighten Flare Nuts on Pressure
Connection Line Fittings
Overtightening flare connections may damage the
threads on the flare nuts or flare connectors, and may
result in leaks. Do not exceed 9 ft·lb (12 N·m) of torque
when tightening brass flare connections.
Avoid Severe Pressure Pulsation at Pressure
Connections
Install pressure connection lines to pressure tap points
away from the compressor, to minimize the effects of
pressure pulsation from reciprocating compressors.
IMPORTANT: After installing control, evacuate
control and pressure connection
lines in accordance with
applicable EPA and other
regulations, to remove air,
moisture, and other
contaminants.
Wiring
P70, P72, and P170 controls for low pressure
applications are available with several switch options
and electrical ratings. Check the label inside the
control cover for model number, switch action, and
electrical rating. (See Table 1 for switch actions and
models.)
Check the wiring terminal designations on the control
switch-block and refer to the following guidelines and
applicable wiring diagrams, when wiring the control.
!
WARNING: Risk of Electrical Shock.
Disconnect power supply before
making electrical connections to
avoid possible electrical shock or
equipment damage.
IMPORTANT: Use terminal screws furnished in
the contact block. Using other
terminal screws will void the
warranty and may damage the
switch.
IMPORTANT: Make all wiring connections in
accordance with the National
Electrical Code and all local
regulations. Use copper
conductors only. Do not exceed
the control’s electrical rating.
L1
L2
Load
Line
M1
Open-High switch action:
opens on pressure rise.
(C and D Models)
L1
L2
Load
Line
M1
Open-Low switch action:
opens on pressure drop.
(A and B Models)
Figure 5: Typical Wiring for SPST Open-Low
Switch and Open-High Switch
(P70A, B, C, D, and P170A, C, D, Models)
1
2
3
L1
L2
Load
Alarm
1 to 3 opens, and 1 to 2 closes
on pressure rise.
Figure 6: Typical Wiring for SPDT Switch
(P70E, F Models)

6 P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin
Line
M1
L1
L2
Load
Line
M2
Alarm
Circuit
Power
Alarm
Main circuit (Line to M2) opens and
auxiliary circuit (Line to M1) closes
on pressure rise.
Figure 7: Typical Wiring for 4-wire 2-circuit Switch
(P70G and H Models)
Line
M1
L1
L2
Load
Line
M2
Line to M1 and Line to M2 open on pressure drop.
L3*
*(L3 is third supply line in 3-phase applications.)
Figure 8: Typical Wiring for DPST Switch
(P72A and B Models)
Table 1: Single Pressure Controls Switch Action, Low Event, High Event, and Models
Switch and Action Low Event High Event Models
Single-Pole Single-Throw
(SPST) Open-low
Cut Out
(Opens Line to M1)
Cut In
(Closes Line to M1) P70A, P70B, P170A
Single-Pole Single-Throw
(SPST) Open-high
Cut In
(Closes Line to M1)
Cut Out
(Opens Line to M1) P70C, P70D, P170C, P170D
Single-Pole Double-Throw
(SPDT)
Opens 1 to 2 and
closes 1 to 3
Closes 1 to 2 and
Opens 1 to 3 P70E, P70F
4-wire, 2-circuits,
1 N.O., 1 N.C.
Open-low
Cut Out
(Opens M2 to Line and
Closes M1 to Line)
Cut In
(Closes M2 to Line and
Opens M1 to Line)
P70G, P70H
4-wire, 2-circuits,
1 N.O., 1 N.C.
Open-high
Cut In
(Closes M2 to Line and
Opens M1 to Line)
Cut Out
(Opens M2 to Line and
Closes M1 to Line)
P70J, P70K, P170K
Double-Pole Single-Throw
(DPST)
Open-low
Cut Out
(Opens M1 to Line and
M2 to Line)
Cut In
(Closes M1 to Line and
M2 to Line)
P72A, P72B
Double-Pole Single-Throw
(DPST)
Open-high
Cut In
(Closes M1 to Line and
M2 to Line)
Cut Out
(Opens M1 to Line and
M2 to Line)
P72C, P72D

P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin 7
Adjustments
Adjustment of the P70, P72, and P170 low pressure
controls vary, depending on the model. The following
guidelines and diagrams illustrate the procedures for
adjusting these controls. Refer to the product label
inside the control cover for model number and switch
action, and check the front of the control cover to
determine if the control is All-Range or MICRO-SET.
(Refer to Table 1 for switch action, low event, and
high event of the various control models.)
All-Range Controls
All-Range pressure controls have a scaleplate that
displays the CUT IN and CUT OUT setpoints. (See the
visible scale on control.) Turning the range screw
adjusts the CUT IN and CUT OUT setpoints up or
down simultaneously, while maintaining a constant
pressure differential. Turning the differential screw
adjusts only the low event on the left side of the scale,
and changes the pressure differential.
MICRO-SET Controls
MICRO-SET low-side pressure controls have a
scaleplate that displays the CUT IN setpoint and
DIFFERENTIAL setting. (See visible scale on control.)
Turning the range screw adjusts the CUT IN setpoint
on the right side of the scale. Turning the differential
screw adjusts the DIFFERENTIAL setting on the left
side, which changes the resulting cut-out pressure.
IMPORTANT: Do not adjust pointers beyond
the highest or lowest indicator
marks on the control’s pressure
scale. Adjusting pointers beyond
indicator marks may damage
screw threads and cause
inaccurate control operation.
Step 1.
Step 2.
Turn screw clockwise to raise low event.
Turn screw clockwise to increase DIFFERENTIAL.
Micro-Set Controls: Turning the differential screw changes the differential setting.
All-Range Controls: Turning the differential screw changes the low event.
Figure 9: Adjusting P70, P72, and P170 Controls for Low Pressure Applications

8 P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin
Limited Knob Adjustment
Some models are supplied with a Limited Knob
Adjustment kit, which limits adjustments to the
pressure control and help to deter over-adjustment or
tampering.
To lock the differential setting and allow limited
adjustment of the low event and high event setpoints,
install the knob on the range screw.
To lock the high event setpoint and allow limited
adjustment of the low event setpoint (on All-Range
controls) or differential setting (on MICRO-SET
controls), install the knob on the differential screw.
To install the Limited Knob Adjustment: kit:
1. Adjust control pointers to desired high event and
low event setpoints (on All-Range controls), or
differential setting (on MICRO-SET controls).
2. Place spacer on the proper adjustment screw.
•All-Range controls (with Limited Knob
Adjustment kit ) have round and knurled
adjustment screws—the spacer must always
be placed on the range screw.
•MICRO-SET controls have square adjustment
screws, always place the spacer on the same
adjustment screw as the knob.
3. Place the indicator plate as shown in Figure 10, to
lock either the range screw or differential screw in
the desired setting.
4. Install the knob on the other adjustment screw,
and tighten the setscrew. A stop on the bottom of
the knob limits screw adjustment to less than one
turn.
IMPORTANT: Use the pressure control settings
recommended by the manufacturer
of the controlled equipment. Do not
exceed the pressure ratings of the
controlled equipment or any of its
components when checking
pressure control operation or
operating the controlled equipment.
IMPORTANT: After installing and adjusting
pressure control, and before
leaving installation, cycle the
controlled equipment several times
(at least three) at normal operating
conditions. Use reliable pressure
gauges to verify proper control
settings and equipment operation.
Adjustment Knob with Set Screw
Indicator Plate
Spacer*
Installation of Knob Kit to
Lock Differential Screw and
Allow Limited Adjustment of
Range Screw
Installation of Knob Kit to
Lock Range Crew, and
Allow Limited Adjustment of
Differential Screw
Differential Screw
Range Screw
Range Screw
*On MICRO-SET controls, place spacer on same adjustment
screw as knob.
On All-Range controls, always place spacer on range screw.
Figure 10: Installing Limited Knob Adjustment Kit
Manual Reset Operation
Pressure controls with the Manual Reset option, lock
out when they reach cut out pressure and must be
manually reset by the user to restart the controlled
equipment. The manual reset mechanism is “trip-free”
and cannot be over-ridden by blocking or tying the
reset button down.
On equipment with locked out controls, first determine
and remedy the cause of the lockout, and allow the
sensed pressure to return to the cut-in setpoint. Then,
press and release the reset button on the front of the
control to restore operation of the controlled
equipment.

P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin 9
Ordering Information
P70, P72, and P170 controls for low pressure
applications are available in a variety of standard and
non-standard models.
Table 2 lists the standard models available through
most Johnson Controls/PENN Authorized Distributors.
Table 3 is a model identification matrix that depicts all
the potential P70, P72, and P170 control models. Not
all control models depicted in Table 3 are
manufactured and available.
Figure 11 illustrates the pressure connection styles
available on P70, P72, and P170 control models.
Contact your Johnson Controls/PENN Authorized
Representative for availability and price.
Table 2: Standard P70, P72, and P170 Controls for Low Pressure Applications
Code
Number
Switch
Action
Range
psig (kPa)
Differential
psi (kPa)
Pressure
Connection
Limited Knob
Adjustment
MICRO-SET Controls (For Non-Corrosive Refrigerants)
P70AB-12 36 in. Cap. with
1/4 in. Flare Nut
P170AB-12
SPST
Open Low
12 in. Hg
to 80
(-41 to 551)
Minimum 5 (34)
Maximum 35 (241) 1/4 in. Male Flare
Connector
Supplied,
but not assembled
ALL-RANGE Controls (For Non-Corrosive Refrigerants)
P70AB-1 1/4 in. Male Flare
Connector
P70AB-2
SPST
Open Low 36 in. Cap. with
1/4 in. Flare Nut
Supplied,
but not assembled
P70CA-1 SPST
Open High
Minimum 7 (48)
Maximum 50 (345)
36 in. Cap. with
1/4 in. Flare Nut None
P70EA-10
SPDT
1 to 3 Open Low
1 to 2 Close Low
5 (34)
Fixed
1/4 in. Male Flare
Connector None
P72AA-1 None
P72AB-1
DPST
Open Low
36 in. Cap. with
1/4 in. Flare Nut Mounted on
Differential Screw
P170AB-2 SPST
Open Low
Mounted on
Differential Screw
P170CA-1 SPST
Open High
20 in. Hg
to 100
(-68 to 690)
Minimum 7 (48)
Maximum 50 (345)
1/4 in. Male Flare
Connector None
ALL-RANGE Controls (Ammonia Compatible)
P70AA-5 SPST
Open Low
P70CA-4 SPST
Open High
20 in. Hg
to 100
(-68 to 690)
Minimum 7 (48)
Maximum 50 (345) 1/4 in. SS Female NPT None
Note: See Dimensions and Specifications for additional model information including Maximum Working Pressure and
Maximum Over-pressure ratings.

10 P—P70, P72, and P170 Controls for Low Pressure Applications Product/Technical Bulletin
Table 3: P70, P72, and P170 Pressure Control Identification Matrix
P70 Various pressure connection styles available on many models (See Figure 11.)
P170 1/4 in. male flare pressure connection only (Style 5, see Figure 11.)
P72 DPST switch only, 3/4 in. conduit opening on most models, (E, F, G, H, J, and K, models not available)
ASPST switch (DPST in P72), Open-low, automatic reset
BSPST switch (DPST in P72), Open-low, manual reset lockout
CSPST switch (DPST in P72), Open-high, automatic reset
DSPST switch (DPST in P72), Open-high, manual reset lockout
E1 hp SPDT switch (n/a in P72), automatic reset
F1/4 hp SPDT switch (n/a in P72), automatic reset
G4-wire, 2-circuit switch (n/a in P72), main switch Open-low, automatic reset
H4-wire, 2-circuit switch (n/a in P72), main switch Open-low, manual reset lockout
J4-wire, 2-circuit switch (n/a in P72), main switch Open-high, automatic reset
K4-wire, 2-circuit switch (n/a in P72), main switch Open-high, manual reset lockout
ANEMA 1 enclosure, no adjustment knob
BNEMA 1 enclosure, with adjustment knob
CNo enclosure, no adjustment knob
DNo enclosure, with adjustment knob
ENEMA 3R enclosure, no adjustment knob
GNEMA 3R enclosure, no adjustment knob
HNEMA 1 enclosure, no adjustment knob, 1/4 in. quick connects
JNEMA 1 enclosure with adjustment knob, 1/4 in. quick connects
NNEMA 1 enclosure no adjustment knob, transportation application
PNEMA 1 enclosure with adjustment knob, transportation application
SNEMA 3R enclosure, no adjustment knob, transportation application
Note: Not all combinations shown on this chart are available. To verify product availability and for quantity orders
of non-standard items, please contact Refrigeration Application Engineering at [phone].
7/16 - 20 UNF-2A Thread;
1/4 in. SAE Male
Flare Connector*
1/4 - 18 NPT Female Thread;
Brass for Use with
Non-corrosive Refrigerants,
Stainless Steel for Use
with Ammonia
Copper Capillary with
1/4 in. SAE Female
Flare Connector
(Style 45 includes a
valve stem depressor.)
Copper Capillary with
1/4 in. Copper Sweat
Copper Capillary with
1/4 in. SAE Female
Flare Connector
with 90° Bend
*Note: Style 5, Connector may require a copper flare saver gasket, which must be purchased separately.1/4 in. SAE Male Flare
Style 13 or 45 Style 37 Style 34 Style 15 Style 5
Figure11: Pressure Connections Styles Available on P70, P72, and P170 Controls