INSTALLATION
For all normal installations, the sensitive bulb should be located so as to be in the average temperature of the controlled medium where there is a good air circulation around the bulb. The bulb should not be attached directly to a wall or surface, but should be held away by mounting brackets. A minimum amount of capillary should be in the controlled area.
The bulb may be mounted in any normal atmosphere, but it should be remembered that the copper element should not be installed in a corrosive atmosphere such as may be found in certain applications.
The switch mechanism may be located in any position provided that it will not be subjected to a temperature above 150°F.
Excessive capillary should be coiled and secured close to the switch mechanism and should be handled with reasonable care to prevent breaking of the seals, kinking or smashing.
CAUTION
Do not dent the sensitive bulb of this control. A dent or a sharp bend will change the calibration and cause the control to cycle at a temperature lower than the dial setting.
ANTICIPATION
Anticipation is a factor introduced into the performance of a control to reduce its natural differential. The sensitive bulb of industrial temperature controls can be located to obtain anticipa- tion by placing it in a position close to the source of the heat. This causes the sensitive bulb to receive heat quicker than the oven proper, causing the control to turn the heat off sooner, thus reducing the differential.
The proper location of the sensitive bulb depends on the equipment design and can be determined only by trial. Care should be taken so as not to put the bulb too close to the source of the heat as this may subject the bulb to damaging tempera- tures.
Equipment that is controlled by anticipated controls does not reach its final or constant temperature on the first cycle of the control. There is a tendency for the temperature to continue to rise after the control first starts cycling. After several cycles, the temperature becomes constant. The greater the amount of anticipation, the greater the tendency toward preliminary up- ward cycling.
The amount of anticipation as measured by the change in calibration caused by the anticipated location should not exceed 25°. Thus, if the control is set to open the circuit at 300°F, the temperature, when it becomes constant, should not be lower than 275°F.
WIRING
All wiring should be done in accordance with local and national electrical codes and ordinances.
If the manufacturer of the heating equipment has supplied a wiring diagram, follow such recommendations.
If none is offered, this diagram shows a suggested circuit.
HOT
LINE
N
HOT |
|
LINE | LOAD |
| |
N |
|
L1L2
COIL
LOAD
Connections for direct control of heaters. | Diagram of connections for operating heating |
| load through a contactor. |
SETTING THE CONTROL
CONTROLS WITH A FIXED DIFFERENTIAL
The indicator (B) points to the temperature at which the contacts open.
To set the control:
Use a screwdriver in the adjusting slot (A) on the front of the control to rotate dial until the desired temperature at which the contacts will open is positioned directly under the indicator (B).
CONTROLS WITH ADJUSTABLE STOPS
1.Loosen stop screw (E) with enclosed wrench.
2.Set dial to original equipment manufacturer's specification.
3.Without moving the dial, move stop tab (F) against indica- tor.
4.Retighten stop screw (E).
“F” STOP TAB | “B” FIXED | |
INDICATOR | ||
|
“A” ADJUSTING
CAUTION
“E” STOP SCREW
SLOT
Setting stop higher than control being replaced could cause personal injury and/or property damage.
FIXED DIFFERENTIAL
2
