FANs 121, 125
Temperature Controls Section
A
Technical Bulletin
A19ZBC
Issue
Date
1291
© 1991 Johnson Controls, Inc.
1
Code No. LIT-121071
Part No. 996-460
A19ZBC Type
Temperature Control
Application
The A19ZBC is used for general
purpose operating temperature
control applications. The control
has a single-pole, double-throw
contact unit and a temperature
range of 0 to 70
°
F (-15 to 25
°
C).
A packing nut assembly, Part
No. FTG13A-600R, (Fig. 2) and
a bulb well No. WEL14A-602R
(Fig. 3) for immersion
applications are available and
are ordered separately, if
required.
All Series A19 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.
Installation
When provided, follow the
equipment manufacturer’s
instructions. If instructions are
not supplied, follow the
instructions in this sheet.
!
CAUTION: Do not dent or
deform the sensitive bulb 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.
Mounting
When installing the control, use
the mounting bracket as a
template and mark the location
for the two mounting screws.
Drill or punch two holes and start
the mounting screws. Place the
slot in the bottom of the bracket
under the head of the lower
mounting screw. Position the
control so the top screw is in the
top slot. Tighten both screws. It
is not necessary to level the
control except for appearance.
For closed tank applications
without a bulb well, use the
FTG13A-600R packing nut.
(See Fig. 2.) Put parts over the
support tube section of the
element and place the bulb in
the tank. Install the 1/2 in. NPT
adapter in the tank opening and
tighten. Screw the packing nut
with the retaining washers and
packing into the adapter as
shown in Fig. 2.
!
CAUTION: Turn Off the
liquid supply and relieve the
pressure before installing or
removing the bulb or bulb
well.
For applications requiring a bulb
well, install the bulb well in the
tank opening. Remove the
bushing from the bulb well and
slide the bushing over the
capillary. Insert the bulb into the
bulb well and replace the
bushing. Push the bulb into
position in the bottom of the well.
Tighten the set screw in the
adapter end to hold the bulb in
position.
Fig. 1 -- A19ZBC Temperature
Control. Note the mounting
bracket on the back of the case.