WIRING AND WIRING DIAGRAMS
ELECTRIC SHOCK HAZARD. Disconnect all power before installing or servicing heater. Failure to do so could result in personal injury or property damage. Heater must be installed by a qualified person in accor- dance with the National Electrical Code, NFPA 70.
ELECTRIC SHOCK HAZARD. Any installation involving electric heaters must be performed by a qualified person and must be effectively grounded in accor- dance with the National Electrical Code to eliminate shock hazard.
1.Loosen and remove bolts securing the main terminal enclosure cover on side of unit. Connect heater to line supply wires at the box lugs located on the contactor according the voltage and fre- quency specified on the nameplate (see Figure 9). Refer to the appropriate wiring diagram which also appears on the inside cover of this enclosure (see Table B and diagrams on page 6).
EXPLOSION HAZARD. Cover joints must be clean before replacing cover. Do not use any gasket materi- al on joint surfaces.
2.Use copper conductors only for supply wires. Refer to name- plate and Table B for size and rating required.
3.Connect supply line ground conductor to the box lug provided on the base plate below contactor input lugs.
Table B – Supply Wiring Requirements
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| 90˚C Size | Max Fuse | Wiring |
Model | kW | Phase | Volts | (ga) | Amps | Diagram # |
3 | 1 | 208 | 10 | 25 | I | |
3 | 3 | 208 | 12 | 15 | II | |
3 | 1 | 240 | 10 | 20 | I | |
3 | 3 | 240 | 12 | 15 | II | |
3 | 3 | 480 | 12 | 15 | II | |
3 | 3 | 575 | 12 | 15 | II | |
5 | 1 | 208 | 8 | 35 | I | |
5 | 3 | 208 | 10 | 20 | II | |
5 | 1 | 240 | 8 | 30 | I | |
5 | 3 | 240 | 10 | 20 | II | |
5 | 3 | 480 | 12 | 15 | II | |
5 | 3 | 575 | 12 | 15 | II | |
7.5 | 1 | 208 | 6 | 50 | I | |
7.5 | 3 | 208 | 8 | 30 | II | |
7.5 | 1 | 240 | 6 | 45 | I | |
7.5 | 3 | 240 | 8 | 25 | II | |
7.5 | 3 | 480 | 12 | 15 | II | |
7.5 | 3 | 575 | 12 | 15 | II | |
10 | 3 | 208 | 8 | 40 | II | |
10 | 1 | 240 | 4 | 60 | I | |
10 | 3 | 240 | 8 | 35 | II | |
10 | 3 | 480 | 10 | 20 | II | |
10 | 3 | 575 | 12 | 15 | II | |
15 | 3 | 208 | 4 | 60 | II | |
15 | 3 | 240 | 6 | 50 | II | |
15 | 3 | 480 | 8 | 25 | II | |
15 | 3 | 575 | 10 | 20 | II | |
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18 | 3 | 240 | 4 | 60 | II | |
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20 | 3 | 480 | 8 | 35 | II | |
20 | 3 | 575 | 8 | 30 | II | |
25 | 3 | 480 | 8 | 40 | II | |
25 | 3 | 575 | 8 | 35 | II | |
30 | 3 | 480 | 6 | 50 | II | |
30 | 3 | 575 | 8 | 40 | II | |
35 | 3 | 480 | 4 | 60 | II | |
35 | 3 | 575 | 6 | 50 | II | |
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4.The fan motor is factory wired at the same voltage, and phase as the heating elements. All motors are thermally protected and con- nected to the main supply contactor. On three phase units, it is necessary to verify that the fan rotation is correct. Air stream discharge must be out front of unit. After connecting unit to line and closing all covers tightly, energize unit momentarily. If air does not exit front louvers, reverse any two supply leads at the box lugs on the contactor or at the supply disconnect.
5.Either of two 1 NPT rigid conduit openings with integral stops may be used for connection to supply line. (See Figure 9 and 10 for locations) Use only NEC approval hazardous locations means of wiring such as mineral insulated cable and fittings or rigid con- duit and seal fittings located as required by installation codes.
EXPLOSION HAZARD. All unused conduit openings must be fitted with plugs that are U.L. recognized for use in hazardous locations.
6.Heaters may be provided with a
7.Installation must include appropriate over current protection devices (fusing or circuit breakers) as required by the National Electric Code in the supply line to the unit. Refer to nameplate for proper current ratings.
8.To operate heaters from an externally mounted hazardous location thermostat, a terminal block is provided for connection (Figures 9 and 10). Remove the factory installed jumper across T2 and T3 on the terminal strip. Wire the thermostat contact leads to these ter- minals. The built in control transformer supplies the unit with either 24V or 120V for internal unit operation. This voltage will appear across the thermostat contacts when they are open. The minimum thermostat contact rating should be 1 amp @ 120 VAC. Refer to nameplate for control voltage of unit. The 1/2 NPT con- duit wiring entry on top of the terminal enclosure should be used to wire the thermostat to the heater (Figure 10).
9.Protection against overheating is provided by a manual reset limit control located within the heat exchanger wiring compartment. (Figure 9) Activation of the control will open the control circuit and energize the pilot lamp (if supplied). If normal airflow is restricted, or stopped, the unit will be cycled off by the manual reset cutout. The manual reset limit control is also designed to shut down the unit completely if the fluid level is low or other heater malfunction occurs.
Manual reset limit control must never be bypassed in the control circuit. If the limit actuates, shut down unit and investigate cause of abnormal operation. Do not reenergize until the problem has been corrected.
Users should install adequate
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