Penn A28PA Series User manual

Installation Guide
Issue Date December 2022
© 2022 Johnson Controls 1
Part No. 996-545, Rev. H www.pennncontrols.com
A28PA and A28PJ Series Two-Stage Temperature Controls
with Type 4X Raintight Enclosures
Application
Important: A28PA and A28PJ Series Two-Stage
Temperature Controls with Type 4X Raintight
Enclosures are intended to provide an input to
equipment under normal operating conditions.
Where failure or malfunction of the control could lead
to personal injury or property damage to the
controlled equipment or other property, additional
precautions must be designed into the control
system. Incorporate and maintain other devices,
such as supervisory or alarm systems or safety or
limit controls, intended to warn of or protect against
failure or malfunction of the control.
Important : Le A28PA and A28PJ Series Two-Stage
Temperature Controls with Type 4X Raintight
Enclosures est destiné à transmettre des données
entrantes à un équipement dans des conditions
normales de fonctionnement. Lorsqu'une défaillance
ou un dysfonctionnement du control risque de
provoquer des blessures ou d'endommager
l'équipement contrôlé ou un autre équipement, la
conception du système de contrôle doit intégrer des
dispositifs de protection supplémentaires. Veiller
dans ce cas à intégrer de façon permanente d'autres
dispositifs, tels que des systèmes de supervision ou
d'alarme, ou des dispositifs de sécurité ou de
limitation, ayant une fonction d'avertissement ou de
protection en cas de défaillance ou de
dysfonctionnement du control.
You can use A28PA and A28PJ series two-stage
electromechanical temperature controls in many
agricultural applications. The A28PA and A28PJ
controls have rugged polycarbonate enclosures and
are UL listed as Type 4X. A28PA and A28PJ controls
are also UL listed for use in National Electrical Code
(NEC) Article 547 Agricultural Environments
(ANSI/NFPA 70).
Two single-pole, double-throw (SPDT) switches
provide independent stage control circuits. You can
wire each switch for open-high or close-high action,
which provides automatic changeover on heating or
cooling applications. The temperature controls include
a jumper across the switches’ red common terminals.
Adjustable A28PA and A28PJ series temperature
controls have O-ring sealed external set point
adjustment knobs and range scales with oversized
markings for easy readability in low light.
Important: Do not dent, bend, uncoil, or otherwise
alter the position of the sensing element, also known
as the coil, mounted on the base of the A28PA and
A28PJ series controls. If you damage the sensing
element, you could change the control calibration
and you void any warranties on the control.
Operation
The circuit between R and Y of the low stage switch
(RYL) closes, and R and B (RBL) opens on
temperature increase to the setpoint, which you can
view on the dial setting. On a further temperature
increase, the high stage switch closes RYHand opens
RBH. The reverse sequence occurs on a temperature
decrease.
Dimensions
Figure 1: A28PA and A28PJ dimensions, in. (mm)

2A28PA and A28PJ Series Two-Stage Temperature Controls with Type 4X Raintight Enclosures Installation Guide
Mounting
Mount the temperature control in a location that
exposes it to the average temperature of the controlled
space. Do not mount the control where unusual heat
or cold can affect it, such as over an animal stall or in
direct sunlight. Avoid locations near doors, windows,
or other sources of non-ambient air drafts. Do not
mount the control on an outside wall or where the
temperature at the sensing element exceeds 140°F
(60°C).
Mount the temperature control to a flat surface with
screws through the holes in the mounting tabs on the
back of the case.
Wiring
!
WARNING: Risk of Electric Shock.
Disconnect or isolate all power supplies before
making electrical connections. More than one
disconnection or isolation may be required to
completely de-energize equipment. Contact with
components carrying hazardous voltage can cause
electric shock and may result in severe personal
injury or death.
ADVERTISSEMENT : Risque de décharge
électrique.
Débrancher ou isoler toute alimentation avant de
réaliser un branchement électrique. Plusieurs
isolations et débranchements sont peut-être
nécessaires pour -couper entièrement l'alimentation
de l'équipement. Tout contact avec des composants
conducteurs de tensions dangereuses risque
d'entraîner une décharge électrique et de provoquer
des blessures graves, voire mortelles.
Important:All wiring must conform to all local,
national, and regional regulations. Use copper
conductors only for all wire connections.
Important: Do not use A28 temperature controls on
applications where the electrical load across the
control’s switch may exceed the electrical ratings
shown on the temperature control’s label.
Important: Use only the terminal screws furnished
with the switch. Using other screws in the switch
voids the warranty, may damage the switch, and
may cause problems in making secure connections.
The wiring terminals of each switch are color coded to
simplify wiring. Red (R) is the common terminal. The
red to yellow (Y) circuit closes on temperature
increase. In standard applications, you can wire from
R to Y to control cooling or ventilating equipment. The
red to blue (B) circuit opens on temperature increase.
In standard applications you can wire from R to B to
control heating equipment.
To make wiring connections, complete the following
steps:
1. Loosen the four cover screws and remove the
cover and knob assembly. Do not remove the
knob, it is secured in the cover. Do not damage
the O-ring.
2. Select the knockout that you want to remove.
3. Place a screwdriver blade on the knockout near
the edge.
4. Apply a sharp blow to the screwdriver handle to
loosen the knockout.
5. Connect an approved watertight conduit fitting to
the conduit.
6. Connect the fitting to the A28PA or the
A28PJ control enclosure.
Note: For flexible conduits, you can reverse Step
5 and Step 6.
7. Insert the wire through the conduit opening.
8. Make the wiring connections to the screw
terminals. See Figure 2, Figure 3, and Figure 4.
9. Ensure that the enclosure O-ring is securely
seated in the groove so that it forms a correct seal
between the cover and case.
10. Replace the cover and knob assembly.
11. Check the alignment of the range adjustment
knob.
Dial
R
B
Y
R
B
Y
A28 Temperature
Control
Low and High Temperature
Stage Switch-Action is:
closes and opens
on temperature decrease.
R to B R to Y
R to Y R to Bcloses and opens
on temperature increase.
Low Temp.
Stage
High Temp.
Stage
996545_2.cdr
Figure 2: A28 temperature control switch action

A28PA and A28PJ Series Two-Stage Temperature Controls with Type 4X Raintight Enclosures Installation Guide 3
Dial
R
B
Y
R
B
Y
A28 Temperature
Control
Factory
Installed
Jumper
Second
Stage
Load
First
Stage
Load
L1
L2
996545_3.cdr
Connect to Y
for cooling.
Connect to B
for heating.
Figure 3: Standard A28 control wiring for a
two-stage control circuit
High
Temperature Low
Temperature
To
Power
Supply
High Speed
Low Speed
To
Fan
Motor
Installer must provide means of disconnection
and overload protection as required.
L1 L1
996545_4.cdr
Dial
R
B
Y
R
B
Y
A28 Temperature
Control
Factory
Installed
Jumper
L2
Figure 4: Standard A28 control wiring for a
two-speed ventilating fan
Setup and adjustments
Turn the knob on the front of the A28 temperature
control to adjust both of the control’s temperature set
points simultaneously.
!
WARNING: Risk of Electric Shock.
Disconnect all electric power sources from the A28
thermostat before removing the A28 thermostat
cover. Contact with internal components carrying
hazardous voltage can cause electric shock and
may result in severe personal injury or death.
ADVERTISSEMENT : Risque de décharge
électrique.
Déconnecter toutes les sources d'alimentation
électrique du régulateur A28 avant d’enlever le
boîtier du régulateur A28. Tout contact avec des
composants internes conducteurs de tensions
dangereuses risque d'entraîner une décharge
électrique et de provoquer des blessures graves,
voire mortelles.
All A28 temperature controls have a fixed differential
on each switch. Some models have an adjustable
inter-stage differential.
To adjust models with an inter-stage differential:
1. Remove the control cover and rotate the adjusting
wheel counterclockwise to increase the
differential. Increase the spread according to the
label on the control.
2. Insert a small screwdriver into the serrated wheel
at the lower left corner of the low temperature
stage switch.
3. Return and secure the cover with the screws when
the adjustments are complete.

4A28PA and A28PJ Series Two-Stage Temperature Controls with Type 4X Raintight Enclosures Installation Guide
Checkout
Before you leave the installation, observe at least
three complete operating cycles of the controlled
equipment to ensure that all components function
correctly.
Adjust the dial to a lower or higher set point and check
the contact action of the switches to ensure that they
operate as shown in Figure 2, Figure 3, and Figure 4.
Repairs and replacement
Do not repair A28 temperature controls in the field.
Contact your Johnson Controls® or PENN sales
representative or authorized distributor for a
replacement control.
Technical specifications
Table 1: A28PA and A28PJ techncial specifications
Product A28PA and A28PJ Type Two-Stage Temperature Controls with Type 4X Raintight
Enclosures
A28PA type
switch electrical ratings,
each switch
Applied VAC 24 120 208 240 277
Motor, full load amperes - 16 9.2 8 -
Motor, locked rotor amperes - 96 55.2 48 -
Non-inductive amperes - 16 9.2 8 7.2
Pilot duty volt-amperes 125 125 125 125 125
Total connected load not to exceed 2,000 VA
A28PJ type
Penn switch electrical
ratings,
each switch
Applied VAC 24 120 208 240 277
Motor, full load amperes - 6 3.4 3 -
Motor, locked rotor amperes - 36 20.4 18 -
Non-inductive amperes - 10 9.2 8 7.2
Pilot duty volt-amperes 125 125 125 125 125
Total connected load not to exceed 2,000 VA
Ambient operating
temperature
-26°F to 140°F (-32°C to 60°C)
Ambient storage conditions
-40
°
F to 140
°
F (-40
°
C to 60
°
C)
Shipping weight
1.2 lb (0.54 kg)
Agency listings
UL Listed; File E6688, CCN XAPX (US) and XAPX7 (Canada)
UL Listed as Type 4X and for NEC Article 547 Agricultural Environments
The performance specifications are nominal and conform to acceptable industry standards. For application at conditions beyond these
specifications, contact Johnson Controls Application Engineering. Johnson Controls shall not be liable for damages resulting from
misapplication or misuse of its products.
Single point of contact
A
PAC:
Europe:
NA/SA:
UK:
JOHNSON CONTROL
S
C/O CONTRO
LS PRODUCT MANAGEMENT
NO. 32 CHANGJIANG
RD NEW DISTRICT
WUXI JIANGSU PROVINCE
214028
CHINA
JO
HNSON CONTROLS
V
OLTAWEG 20
6101 XK ECH
T
THE NETHERLANDS
JOHNSON CONTRO
LS
57
57 N GREEN BAY AVE.
GLENDALE, WI 532
09
USA
JOHNSON CONTROLS
T
YCO PARK
GRIMSH
AW LANE
MANC
HESTER M40 2WL
UNITED KINGDOM
www.penncontrols.com
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