European Refrigeration Controls Catalogue
Catalog Section
1
Product Bulletin
A25
Issue
25/04/2003
© 2003 Johnson Controls Inc.
Catalogue Section 1
Order No. P
D-
A25-E
PSC9629
I
ntroduction
These warm air limit controls "lock out" on a
temperature increase to the control setpoint.
Manual reset is required to re-close the
electrical contacts. A typical application is to
stop air-conditioning or ventilating fans in the
event of excessive return air temperature, as
from a fire.
D
escription
A rod and tube type sensing element actuates
the switch contacts. Main contacts (1 - 2) are
normally closed, and open when the
temperature at the element rises to the dial
setpoint. Contacts are re-closed only by
operation of the reset lever. The reset lever is
"trip-free" and cannot be used to block contacts
in a closed position.
L
ocation
Select a location in the duct or plenum where the
temperature element senses the average
temperature to be controlled and is in free air
circulation.
M
ounting
The instrument is mounted by means of the
flange which is supplied with the control. The
element is to be inserted in the duct and must be
in the airstream as much as possible. It should
not be in contact with any object inside the duct.
A25CN
N
ote
These controls are designed for use only as
operating controls. Where an operating control
failure would result in personal injury or loss of
property it is the responsibility of the installer
to add devices or systems that protect against,
or warn of, control failure.
A
djustment
These thermostats are standard available with a
knob adjustment. This knob can be removed in
the field to provide screwdriver adjustment.
Feature and Benefits
Rod and tube type of element
Gives maximum response
Allows high maximum element temperature
Adjustable duct mounting flange
Allows various lengths insertion of the element
into the airstream
Trip-free manual reset
Override is not possible in the control function
Dust-tight Penn switch
Prevent pollution of the contacts by
electromagnetic influences
Serie A25CN
Limit Control Manual Reset
