Robertshaw Ranco C12 Installation Data

DESCRIPTION/APPLICATION
The Ranco C12-1800 and the O18-100 are used to control the ice bank
®
size on beverage dispensers and other refrigeration systems which use
an ice bank for thermal storage. The control bulb senses the ice bank
by having a water-based fill which expands upon freezing and contracts
upon thawing. This change in volume is transmitted by a hydraulic
action through the capillary to operate the control switch.
Both the C12-1800 and the O18-100 (which has a NEMA 1 enclosure)
have a single pole, single throw (SPST) switch. They may be used to
directly control a single phase compressor; to control the pilot duty
circuit of a contactor for single or three-phase compressors; or to
control a pilot duty circuit for a liquid line solenoid valve.
CONTROL OPERATION
(For both C12-1800 & O18-100)
The ice bank control is factory set and no field adjustments are to be
made. It is designed to shut off the refrigeration system when the ice
has built-up beyond the bulb by approximately 1/8 inch. The control
switch will reclose when the ice has melted back, exposing a portion of
the bulb.
1st Cycle Effect
When the system is first put into operation, or returned to service,
or after a prolonged off cycle, there will be a long running period
to build the ice bank. During this first cycle, the ice bank may build
approximately 1/4 inch larger than normal. However succeeding cycles
will operate at the normal differential of approximately 1/8 inch of ice
bank.
CAUTION To prevent possible electrical shock or equipment
damage, disconnect electrical power to unit before
and during installation. DO NOT restore electrical
power to unit until the control is properly installed
and grounded. DO NOT locate the control in an
explosive atmosphere as a safety hazard can result
due to possible spark generation in the control.
Controls are not to be located in areas of splashing
water or extreme moisture, dirt or dust, or in
a corrosive or explosive atmosphere. These
environments can shorten control life.
1531080C.indd 1
INSTALLATION DATA
iCe bank COnTROLS
CONTROL BODy mOUNTINg
The C12 and O18 can be mounted in any position. Mount the control in
a location that will permit proper capillary routing and bulb mounting
(see following sections) and is away from moisture and splashing
water. DO NOT twist or strain the control body as this may shift the
calibration. Use only the mounting holes provided; no other holes are
to be added to the control frame.
C12 only
The tips of the mounting screws must not extend through the
mounting bracket so as to touch the control body. Make sure that the
mounting surface is flat to prevent straining the control.
O18 only
Mount on an existing bracket, on the flat bracket provided, or surface-
mount without a bracket. When attaching the control to a bracket use
the 10-32 x 3/16 screws provided and the two tapped holes in the
back of the control. If other mounting screws are used, they must not
enter the control more than 1/8 inch to avoid damage. When surface
mounting the control, use the .20 inch holes in the back of the control
frame which can be accessed by removing the front cover. Make sure
the surface is flat. Mounting to an uneven surface may cause improper
control operation.
1
C12 & O18
O18-100
C12-1800
3/13/15 3:58 PM