Chromalox PG417-3 specifications Wiring, Operation

Figure 3

INSTALLATION

4.Refer to Figure 2. Assemble one flat lock nut onto one end of each support tube or conduit and thread them into the tapped openings in top of heater. One of these support tubes contains three insulated wire leads. Handle with care to avoid damage to lead insulation.

WARNING: Do not cut the support tube for in doing so the minimum 12” clearance to ceiling will be violated resulting in excessive ceiling temperatures. Tighten lock nut securely against heater case.

5.Slip the canopies loosely over the fixture support tubes.

6.Assemble remaining locknuts onto ends of support conduits. Flat nut goes on first; spherical nut last with its convex side facing heater. See Figure 2. There should be full thread engagement at the top spherical nut. Allow about 1/2” spacing between nuts to facilitate hanging to brackets. Set the assembly aside.

7.WARNING: Hazard of Electric Shock. Disconnect all power to ceiling wiring box to which one heater support will be fastened.

8.Install special cover plate and saddle bracket, provided with heater, over ceiling wiring box after fishing insulated power leads and ground lead, if provided, through large opening in cover plate. Use mounting screws provided with wiring box.

9.Mount remaining saddle bracket to ceiling at the remaining planned point of support. The brackets should be on B dimen- sion centers given in Specifications — Table A.

10.Raise heater assembly, and slide both spherical nuts through slot in saddle brackets until spherical nut rests in the slot depressions. Run bottom lock nut up against bracket to lock the assembly into place.

3-1/1/4or 4" octagonal box to be installed in ceiling at one end of heater location. (Cus- tomer furnished).

Cover Plate

Spherical Locknut

Saddle Bracket

Flat Locknut

3/8” Stem

Canopy

Flat Locknut

Figure 2

WIRING

WARNING: Hazard of Electric Shock. Any installa- tion involving electric heaters must be grounded to earth to eliminate shock hazard.

1.All wiring to heater wiring box shall be in accordance with National Electrical Code and/or local wiring code.

2.Power conductors should be sized to handle 125% of heater current given in Specifications — Table A.

3.Complete electrical wiring between heater leads and power leads using insulated wire nuts. Tuck excess lead around and behind saddle brackets.

4.The green colored ground lead should be

connected to ground lead from wiring box, or if such lead is not provided, then the ground lead should be grounded to the con- duit box to insure ground continuity. Note: If heaters are to be suspended more than 12” below ceiling, the heater support tubes should terminate into a Crouse-Hinds Type C Condulet in line wiring box where splice to power leads can be made (See Figure 3). A 3/8” pipe or conduit extension of the desired length from top of Condulet can then terminate at the ceiling wiring box uti- lizing cover plate, brackets, and lock nuts as with conventional installation.

5.To complete installation raise canopies to completely enclose brackets and electrical wiring. Tighten set screw.

6.If wiring from heater becomes damaged or requires replace- ment, it should be replaced with special high temperature wire as furnished with heater. Replacement wires can be ordered from Chromalox. (See RENEWAL PARTS section.)

	The VC or
	VCR	SKR
120 or	15 or 30
		Heaters
240V	Second
		Wired 1ø
	Input
	Controller

Maximum number of Heaters limited by 25 AMP. — 120 Volt, 20 AMP. — 240 Volt Controller Rating.

		Figure 4
		Contactor
120, 208, 240, 275,
480 Volt Single	{
or Three Phase		SKR Heaters
		Wired 1ø or 3ø
120 or	Input	Limiting Thermostat (Optional)
240V {	Control
		Single Phase Wiring — Solid Line
		Three Phase Wiring — Dotted Added

(Type VC or VCR) when voltage and load current exceed controller capacity

Figure 5

SKR Radiant Heater Control by Input Controller

OPERATION

DANGER: Fire Hazard. This heater is not intended for use in hazardous atmospheres where flamma- ble vapors, gases, liquids or other combustible atmospheres are present as defined in the National Electrical Code. Failure to comply can result in explosion or fire.

1.Although most heaters operate at full capacity, it is possible to reduce heating capacity with an Input Controller (Chromalox Type VC or VCR — check factory) which can be manually set to turn on heaters from 4% to 100% of a 15 or 30 second operating cycle, providing, in effect, infinite control of heater output. Refer to Figures 4 and 5 as may be appropriate to your installation.