Operation, Maintenance, Wiring Diagrams | Chromalox UB-502D, UB-752D

WIRING

Note: All wiring should be done in accordance with local codes and the National Electrical Code by a qualified person.

WARNING: Hazard of Electric Shock. Any installation involving electric heaters must be effectively grounded in accordance with the National Electrical Code to eliminate shock hazard.

1.Connect heater according to the voltage and frequency speci- fied on the nameplate and using the appropriate wiring diagram (Figures 3 thru 8).

Note: Be sure to check voltage rating of the fan motor which is either 120, 208 or 240 volt, single phase since heater circuit could be 480 volts, single or three phase.

2.If a transformer is used to step down the voltage for operating the fan motor, use appropriate wiring diagram (Figures 5 or 7).

3.Heaters are not provided with a control switch and should be controlled by a magnetic contactor (integral or external) and a separately mounted thermostat. External contactor is not nec- essary with heaters having a model number suffixed with the letter “R”.

4.Protection against overheating is provided by an internal auto- matic thermal cutout which opens the electric circuit if the nor- mal air-flow is restricted or stopped. Cutout automatically energizes heater on removal of the obstruction.

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

OPERATION

DANGER:

1.Do not restrict air-flow through the heater by placing fabric or other obstructions in front of or behind the heaters. With some combustible materials, the resulting high discharge tempera- tures could cause a fire.

2.This heater is not intended for use in hazardous atmospheres where flammable vapors, gases, liq- uids or other combustible atmospheres are present as defined in the National Electrical Code. Failure to comply can result in explosion or fire. For these applications see Bulletin PDS CXH-EP PF305.

MAINTENANCE

WARNING: Turn off all power to service heater. Do not attempt to service heater while unit is operating as there is hazard of electric shock, injury from operat- ing fan, and burns from hot heating elements.

1.Fan motors in these heaters are provided with sealed ball bear- ings, factory lubricated, requiring no further lubrication under normal service conditions.

2.Following long periods of idleness, heater should be vacu- umed before start-up, to remove accumulated combustible par- ticles which otherwise may smoke or incinerate on initial heat up.

3.Periodically inspect all electrical connections and terminals to avoid electrical wiring difficulties. Inspect all wiring for frayed or worn insulation.

WIRING DIAGRAMS

Figure 3

Use with:

UB-502D

120V, 1Ø 208V, 1Ø or 3Ø 240V, 1Ø or 3Ø

UB-752D

208V, 3Ø

Control Source for

Separately Wired Motors 120 or 240 Volts, 60 Cycle

Fused	Fused
Switch	Switch
	Contactor
	When Heater and

}1 or 3 Phase 60 Hz Power Supply 120, 208 or 240 Volts

Heater

Ground

Heater Bank

1Ø Motor

Wiring Comp't

Baffle

240V, 3Ø

Motor Voltage are similar

Thermostat When Used

This Wiring

by Customer

For 3 Phase Only

Figure 4