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©9/2005 GSA Industries (Aust.) Pty. Ltd. ABN 71 004 784 301
Section 1
1
Air Conditioner Controls
97
152
Ranco Type C17 Thermostats
For Heat Pumps or Two Stage Operation. The C17-177 Thermostat is a standard cycling control with
two electrically separate switches for automatic changeover on heat pumps.
This control completes two electrical circuits in response to temperature changes for either automatic
change-over on heat-cool cycling or on two-stage operations.
The C17-334 Thermostat is the same as the C17-177, except one switch is adjusted to cycle within the
‘cut-out’ and ‘cut-in’ events of the other (differential within a differential).
Field adjustment is not generally recommended for any of the Series C17 Controls. Cross ambient
sensing bulb 9.5mm x 230mm.
Electrical Ratings: 240 VAC. FLA 20. LRA 78.
Replacements:
C17-334 replaces C17-308, 316, 503, 506
C17-177 replaces C17-140
t
Switching Sequence
Switch ‘A’
Terms
Cut-out
°C
Cut-out
°C
Cut-in
°C
Cut-in
°C
Terms
Switch ‘B’
Cat.
No.
152085 C17-334
9.4
3.6
915
Varifix
2 & 1
18.3
20.3
4 & 5
21.1
17.5
152177 C17-177
16.7
2
660
16
2 & 3
19.7
17.8
4 & 5
21.7
19.7
Part
No.
Range
°C
Diff.
K
Cap.
Length
mm
Shaft
Length
mm
Ranco Type A22 Adaptable RAC Thermostat
The function of the A22-2453 Adaptable Control is to cycle an SPDT switch in response to changes of
temperature.
Switch is operated by the expansion and contraction of the bellows in response to temperature
sensing by a cross ambient fill bulb and capillary.
Range adjustments are limited to the rotation of the dial for the required temperature set point.
Differential screw adjustment in the insulator block is for factory callibration use only and is NOT to
be adjusted in the field.
Ranco Type C12 Thermostat
The C12-5010 Cross Ambient Thermostat will perform one of two functions – Cooling Only or Heating
Only. (For Heating-Cooling operation, a manual selector switch is necessary for heat pump applications
since the C12 alone will not automatically perform this function). The switch is basically an SPDT
snap-acting type. Normally closed contacts open on a drop in temperature.
Field adjustment is not recommended on the Range and Differential screws. However, there is a dial
adjustment for a wide temperature range. The bulb of the liquid filled power element is the
controlling point regardless of the temperature at the bellows and capillary tubing.
Ambient temperatures have an effect on the switch operation of the C12 control. A temperature of
27°C is the selected ambient point used by the factory on control calibration. A change in ambient
temperatures above or below 27°C will shift the setting slightly lower or higher respectively.
Electrical Rating: 240 VAC. FLA 20. LRA 80.
t
Bulb and
Capillary
Application
Cat. No.
Part No.
Temperature °C
Switch
Action
Differential
K
Cold Out
Cold In Warm In
2.2
9.5mm x 100mm
Air
152150
A22-2453
SPDT
15
17.8
33.3
Fixed
990mm Cap.
Conditioner
Cross Ambient
Electrical
Rating 240 VAC
9.5mm x 230mm
152081
C12-5010
15.6 to 36.7
1.7 Fixed
Close on Temp.
660mm Cap.
FLA 20
Rise
Liquid Filled
LRA 78
Contacts
Cat. No.
Part No.
Range °C
Diff. K
Bulb and
Capillary
