Johnson Controls Penn A19K Series User manual

Installation Sheets Manual 121
Temperature Controls Section
Technical Bulletin A19K, A28K
Issue Date 0119
© 2019 Johnson Controls 1
Code No. LIT-121078
Part No. 996-241, Rev. A
A19K, A28K Series
Industrial Controls
Application
These controls are for
refrigeration, air conditioning
and heating applications.
Control ranges are available to
cover working temperatures
from -30 to 550°F (-35 to
288°C). Controls have NEMA
3R rainproof enclosure for a
broad range of industrial and
general purpose applications.
The A19 single-stage controls
are available with open low,
open high or SPDT contact
action. The A28 two-stage
controls have SPDT contact
action on both switches.
All Series A19K and A28K
controls are designed for use
only as operating controls.
Where an operating control
failure would result in
personal injury and/or loss of
property, it is the
responsibility of the installer
to add devices (safety, limit
controls) or systems (alarm,
supervisory systems) that
protect against, or warn of,
control failure.
Operation
When the temperature increases
to the control dial setting on the
single-pole, double-throw model,
the circuit between “R” and “Y”
closes. Simultaneously the
circuit between “R” and “B”
opens.
Figure 3 illustrates the two-stage
operation of the A28KA and
A28KJ. On a temperature
increase to the dial setting, the
circuit between “R” and “Y” of
the low stage switch (RYL)
closes. Simultaneously the
circuit between “R” and “B” (RBL)
opens. On a further increase in
temperature the high stage
switch operates and closes RYH
while simultaneously opening
RBH. The reverse sequencing
takes place on a temperature
fall.
Installation
Mounting
Mount the control with the
conduit connector pointing
down. Mount to any flat surface
with screws or bolts through the
rubber bushing in the three
mounting feet. (See Fig. 1.)
!
CAUTION: Do not dent or
deform the sensitive bulb
(element) of this control. A
dent or deformation will
change the calibration and
cause the control to cycle
at a temperature lower
than the dial setting.
When installing the bulb in a
closed tank, turn off liquid
supply, relieve pressure and
lower liquid level below the
opening before installing or
removing the bulb or bulb well.
For closed tank applications
without well assembly Part
No. FTG13A-600R packing nut
assembly may be supplied. This
packing nut is for applications
where the temperature does not
fall below -35°F (-37°C) or
exceed +250°F (121°C).
Maximum liquid pressure limit is
150 PSIG (1034 kPa). See Fig.
4 for sequence of installation.
Put parts over support tube
section of element, placing bulb
into tank. Tighten 1/2 in. NPT
adapter. Screw packing nut into
adapter with the retaining
washers and packing in place as
shown.
To install models supplied with
bulb well, first install bulb well
into tank. Remove bushing from
bulb well and slide bushing over
capillary. Push bulb into position
in bottom of well. Replace
bushing into bulb well.
Tighten set screw in end of
adapter to hold bulb in position.
See Fig. 5 for bulb well
illustration.
Wiring
!
WARNING: Disconnect
power supply before
wiring connections are
made to avoid electrical
shock or possible
damage to equipment.
Fig. 1 -- Industrial control with
remote bulb.

2A19K, A28K Technical Bulletin
Make all wiring connections
using copper conductors only,
and in accordance with the
National Electric Code and local
regulations.
Remove the knob by loosening
the set screw and remove the
cover to make wiring
connections. Make splices in
junction boxes using solderless
connectors or by soldering and
then taping the connections.
Do not use on applications
where electrical ratings exceed
the rating shown on the control’s
label.
!
CAUTION: Use terminal
screws furnished (8-32 ×
1/4 in. binder head).
Substitution of other
screws may cause
problems in making proper
connections.
Adjustment
The setting is changed by
turning knob on front of control.
Checkout Procedure
Before leaving the installation,
observe at least three complete
operating cycles to be sure that
all components are functioning
correctly.
Check for correct operation as
follows:
1. A19K -- Ventilating or
Cooling System: Turn dial
clockwise to a setting above
temperature of controlled
medium. Fan or cooling
system should be off.
When dial is turned
counterclockwise, the fan or
cooling system should turn
on at approximately the dial
setting.
2. A19K -- Heating System:
Turn dial clockwise above
the temperature of
controlled medium. The
heating unit should be on.
When dial is turned
counterclockwise, the
heating unit should turn off
at approximately the dial
setting.
3. A28K -- When wired as
shown in Fig. 3, the damper
should open as the dial is
turned counterclockwise.
The devices should operate
in reverse sequence when
the dial is turned clockwise
to a higher setting.
If the controls do not operate in
the manner described above,
check all wiring for short circuits
and tightness of wiring
connections. If controlled devices
operate in reverse (start in high or
fully open position), check wiring
as it is probably reversed.
Repairs and Replacement
Field repairs must not be made.
For replacement control, contact
the nearest Johnson Controls
distributor.
www.penncontrols.com
® Johnson Controls and PENN are registered trademarks of Johnson Controls in the
United States of America and/or other countries. All other trademarks used herein are the property
of their respective owners. © Copyright 2019 by Johnson Controls. All rights reserved.