Chromalox PK413-4 specifications General, Mounting, Wiring, Sensing Bulb, Capillary Tube

GENERAL

NOTICE: Type AR-EP controls are designed for temperature con- trol service only. Because they do not fail safe, they should not be used for temperature limiting duty.

WARNING: Users should install adequate back-up controls and safety devices with their electric heating equipment. Where the consequences of failure may be severe, back-up controls are essen- tial. Although the safety of the installation is the responsibility of the user, Chromalox will be glad to make equipment recommendations.

Principle of Operation — Control action of these thermostats is provided through the principle of liquid volume change. With a variation in temperature, the liquid in the sensing bulb expands or contracts, causing a bellows to actuate the switching mechanism. Housing — The control housing and cover assembly is of heavy- duty cast aluminum.

Control Range — The following temperature ranges are available:

Fahrenheit

0° to 100°	200° to 550°
60° to 250°	300° to 700°

Process Temperature Differential — is variation in controlled process temperature between maximum, when thermostat turns OFF and minimum, when thermostat turns ON. This spread in temperature may be minimized by —

1.Making sure control is mounted to vertical surface. (See Step 1, MOUNTING section.)

2.Avoiding excess heating capacity (oversized heaters).

3.Locating control sensing bulb in optimum position between heat source and work.

In general, it is difficult to predict the actual operating dif- ferential of a given process. Temperature differential may be as low as 4°F for low range controls to as high as 17°F for high- er range controls since the differential is a percentage function of the dial range.

Packing Glands — If a sealed or leak-proof connection is required at the point where the capillary enters the oven, tank, pipe or simi- lar equipment, an appropriate packing gland is available as an optional part. (Model CCF-25A, CCF-25D or CCF-25E)

MOUNTING

Note: Do not mount thermostat where it will be subject to vibra- tion, shock, grease, dust, lint or corrosive vapors. Do not mount adjacent to a large magnetic contactor, as vibration and shock will cause thermostat to interact erratically — resulting in chattering of the contactor.

The air temperature in and around the thermostat enclosure should be kept as near to normal room temperature as possible...

never above 150°F.						Mounting
1.	Thermostat must be mount-
	ed in a vertical position only.					Lugs	3"
2. Use sheet		metal		or	wood
	screws through the two 5/16”
	diameter mounting holes in
	mounting	lugs		to mount
3.	control (see Figure 2).						7 3/8 "
	For controlling platen or die
	temperatures,		insert		entire
	sensing bulb into drilled holes
	selected for snug slip fit.
	The longer, more sensi-
	tive Style 9 bulbs should be
	used for controlling air tem-
	peratures or pipe line heating.					Capillary
4.	NOTICE:
						Seal
	A. Bending		or	deforming		Fitting
	sensing	bulb		will	alter	Figure 2
	control	calibration —

requiring recalibration after installation. See CALIBRA- TION section, page 3. If necessary, Style 9 bulbs can be coiled to 1” I.D. (see Figure 3).

B.Do not kink capillary tube. The resulting constrictions in fluid flow can destroy control function or broaden temper- ature differential. Minimum capillary tube bending diame- ter is 1/2” I.D. (see Figure 4).

C.Any deformations of bulb or capillary that result in leakage of fluid from control renders control inoperative.

1”

Figure 3

(Sensing Bulb)

Do Not

Bend or Kink

Crimped End

1/2”

Rod

Figure 4

(Capillary Tube)

D.Avoid passing control capillary tube through zones whose temperature is in excess of controlled process temperature. Erratic control or destruction of control function may result.

WIRING

WARNING: Hazard of Electric Shock. Disconnect all power before wiring or servicing this control. Failure to comply can result in electrical shock or electrocution.

1.Electric wiring to heater must be installed in accordance with National Electrical Codes and local codes. WARNING: Use copper conductors only.

2.Entrance for wiring is provided by one 3/4” NPT hole in the top of the housing. Wiring to control housing must be in rigid con- duit also in accordance with National Electrical Codes (NEC) for hazardous locations.

3.Set thermostat knob to OFF position and remove cover plate by loosening and removing four (4) fastening screws (see Figure 5).

Figure 5

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