Nortron B Series Electric Furnace

Safety Precautions

• Never tamper with the unit or its controls. Contact a specialized contractor for any failures. DO NOT ATTEMPT repairs.
• When using a humidifier, ensure the heating element bank is not damaged.
• Poor air filter maintenance or unbalanced static pressure may decrease performance.
• Always use genuine Nortron parts for maintenance and service. Using unbranded parts or operating the unit without an air distribution duct will void the warranty.
• Using jumpers to simulate heat demand is strictly forbidden.
• Risk of electrical shock: Disconnect power before installation, servicing, maintenance, or field wiring. Replace all panels before operating. Failure to do so can result in severe injury or death.
• Wear safety glasses and gloves when installing, servicing, or cleaning the unit.
• Use high-quality, name-brand thermostats for optimal furnace performance.
• Comply with all local and national code requirements, which may supersede those in this document.
• Do not store or use gasoline or other flammable liquids and vapors near this unit or any other appliance.
• These instructions are for qualified personnel trained in installing this type of furnace. Improper installation can lead to equipment damage and hazardous conditions.
• This furnace is not watertight and is not designed for outdoor installation. Outdoor installation can lead to hazardous electrical conditions and premature failure, voiding the warranty.
• Do not block combustion air openings. Blockage can cause overheating, fire hazards, and bodily harm.
• Ensure an uninterrupted electrical ground connection to minimize injury from electrical faults.
• Do not use this furnace as a construction heater, as it exposes the unit to abnormal conditions and contaminated air, potentially leading to premature failure or vent failure.
• The owner/user is responsible for maintaining the furnace surroundings free from combustible materials, and ensuring the ambient air has no excessive dust concentration or humidity. Never operate without an air filter.
• Before performing any service, ensure all utilities are turned OFF upstream of the appliance, unless operations specifically require power to be on.
• All questions regarding operation, maintenance, or warranty should be directed to the company where the product was purchased.

CAUTION

• Never burn garbage or paper in the heating system and keep flammable materials away from the unit.
• Return air grilles and warm air registers must not be obstructed.

Follow all local and national code requirements for electrical installation, heating equipment, wiring, and flue connections, including ANSI/NFPA 70 (National Electrical Code) and CSA C22.1 (Canadian Electrical Code).

Dimensions

The furnace dimensions are provided in the following diagram:

[Diagram showing side and front views of the furnace with key dimensions and knockout locations labeled A, B, C. Filter frame dimensions and return air opening size are also indicated.]

Wiring KO's:

• A: Ø 1 3/8" [35mm]
• B: Ø 1 1/4" [32mm] AND Ø 3/4" [44mm]
• C: Ø 7/8" [22mm] AND Ø 2" [50mm]

General Requirements and Specifications

Installation Environment:

• Install in a dry, non-corrosive, well-ventilated environment without excessive dust.
• Ambient temperature: between 10°C and 27°C. If ambient temperature is 10°C or less, the plenum must be insulated for a minimum of 10 ft. linear length.

Installation Details:

• LOCATION: Centrally locate the furnace to the heating area.
• POSITIONS: Can be installed for vertical, horizontal, or downflow operation. When horizontal, the door should not be on top; it should be on the side to ensure proper motor bearing positioning. For vertical downflow, use "L"- or "T"-shaped plenums with no openings directly below the furnace.
• INSTALLATION CLEARANCES: Units are approved for "zero inch" clearance as shipped. Check the data label for any additional required clearances.
• TEMPERATURE RISE: Furnaces are shipped to operate at 0.20" W.C. (50 Pa) external static pressure and are certified for operation up to 0.50" W.C. (125 Pa). Refer to the specification chart for temperature rise tables and adjust the unit as necessary.
• SERVICE CLEARANCE: Units are serviced from the front. Maintain at least 24" (610 mm) clearance in front of the door.

Specifications Table:

Flow Rate vs. Static Pressure:

WARNING:

• *FACTORY SETTINGS.
• **These models must NOT be set to run continuously at LOW speed due to overheating risks. They are certified for HIGH and MED speeds only.

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.

Operating Options

The furnace ships in "Standard Heating Mode" (all switches Down). When the thermostat calls for heat, automatic controls activate the furnace.

The blower operates at low speed initially and automatically switches to a pre-programmed heating speed as additional elements are activated by time delay relays. The timing of this speed change depends on furnace size and the SEASON SELECT switch setting (COLD or MILD).

RECIRCULATION MODE:

• ON: The blower runs continuously at low speed for even air distribution. It automatically adjusts to the required heating speed when heating elements are activated by the thermostat.
• OFF: The blower motor operates in the standard heating mode, controlled by the thermostat.

[Diagram illustrating the Recirculation Mode switch.]

SEASON SELECT:

• MILD: For spring and fall, approximately half the elements are deactivated to reduce heating capacity.
• COLD: All elements are active and controlled by the thermostat.

NOTE: If using an outdoor or two-stage thermostat, the SEASON SELECT switch MUST be in the MILD position.

[Diagram illustrating the Season Select switch.]

Breakers

B Series furnaces have breakers on the front panel to protect heating elements from overcurrent. If an overcurrent occurs, the breakers open to cut power to the elements.

• The number of breakers varies by model: 21B10M has none; 21B15M, 21B18M, 21B20M, and 83B13 have 2; 21B25M and 83B24 have 3. Refer to Section 8 for wiring diagrams.

WARNING: Breakers only cut power to heating elements, not the entire furnace. Use the main electrical panel to turn off power to the unit.

Installation Notes

Cold Air Return

The duct can attach to the side, rear, or bottom. For side returns, remove four 1 1/2" (38 mm) knockouts to create an 18" x 18" (457 mm x 457 mm) opening. Mount the filter frame over the opening (open side facing front) and attach the 19" x 19" (483 mm x 483 mm) air duct to the frame's flanges.

For bottom mounting, remove the bottom plate screws, discard the plate, and attach the filter frame to the bottom flanges (open side facing front).

Electrical Wiring - Power Supply

Furnaces are factory-wired. A separate breaker requires a two-wire plus ground supply for single-phase units and a three-wire plus ground for three-phase units. Ensure the ground conductor is securely attached to the furnace ground lug and supply wires to the terminal block.

NOTE: A third (neutral) conductor is required if using an FK120 kit for an air cleaner and/or humidifier.

WARNING: Use appropriate gauge copper wire. Electricians must ensure wiring and connections comply with the latest Canadian Electrical Code and local codes.

Connecting and Adjusting the Low Voltage Thermostat

Use only Class 1 wires inside furnace compartments. Connect thermostat wires to the low voltage terminal block inside the furnace, following the thermostat's diagrams.

• Heating: R & W terminals control single-stage heating.
• Cooling: R & Y terminals control cooling. Single-stage cooling uses "Y/Y2"; two-stage uses "Y1" (first stage) and "Y/Y2" (second stage).

Ensure the thermostat is level and properly located.

CAUTION: Properly set the heat anticipator in the thermostat before operation. Measure current draw with an AC meter (2A range for up to 20 kW, 4A for larger units). Set the anticipator to its highest setting, disconnect the "W1" wire, connect the meter between the "W1" terminal and the loose wire, run the furnace for 3-4 minutes with all elements on, and reset the anticipator to match the meter reading.

Use in Mobile Homes

Models from 10 kW to 20 kW are certified for "L"-shape and "T"-shape shallow duct installations with the FSB-1 sub-base in downflow applications where supply air ducts pass through the floor. Recommended floor opening size: 14 1/4" x 14 1/4" (362 mm x 362 mm). The duct system's external static pressure must not exceed 0.50" W.C. (125 Pa).

Shallow Duct Area Requirements:

Using Optional Equipment

Two-Stage or Outdoor Thermostat

The SEASON SELECT switch must be in the MILD position. These controls are compatible with all furnaces except the 10 kW model. Follow the thermostat's instructions and the furnace wiring diagram.

Heating Stages:

Air Conditioning

The furnace includes controls for adding air conditioning. The evaporator coil can be installed in the plenum, centered over the furnace's "chimney", 4" to 6" (102 mm to 152 mm) above the furnace top. Ensure no air bypasses the cooling coil during cooling operation. A bypass damper can be used for heating to allow air to bypass the coil when it's closed in summer.

[Diagram showing typical air-conditioning field wiring connections between the furnace and condenser.]

Wiring Color Code:

Wiring Diagrams

WARNING: Risk of electric shock. Disconnect power before installation, servicing, maintenance, or field wiring. Replace all panels before operating. Failure to do so can result in severe injury or death.

[Diagram 1: Wiring diagram for Nortron B Series 15 kW and 20 kW models, showing single-phase connections, breakers, relays, transformer, and thermostat connections. Includes color code and legend.]

[Diagram 2: Wiring diagram for Nortron B Series 25 kW models, showing single-phase connections, breakers, relays, transformer, and thermostat connections. Includes color code and legend.]

[Diagram 3: Wiring diagram for Nortron B Series Three Phases 13 kW to 24 kW models, showing three-phase connections, breakers, relays, transformer, and thermostat connections. Includes color code and legend.]

Service Parts

Use only Nortron genuine replacement parts for optimal unit performance and safety. Third-party parts may cause damage and reduce performance, leading to premature failure. Contact a certified service depot for parts and repairs.

Time Delay Relays (Sequencers):

Other Parts:

[Exploded view diagram of furnace components with numbered parts corresponding to the table.]

Maintenance

• MOTOR: Lubricated for life; no oiling required.
• FILTERS: Size: 20" x 20" x 1" (508 mm x 508 mm x 25 mm). Inspect and replace when dirty. Typically, replacement is needed twice per heating season, possibly a third time with continuous blower operation.

Thermal Cut-outs:

• Automatic reset thermal cut-out opens at 100°F (38°C), de-energizing elements until reset.
• Manual reset thermal cut-out opens at 130°F (54°C); requires front panel removal for manual reset.

WARNING: Cut power supply (240V or 208V) before removing the front panel. Unit breakers do not cut power to the entire furnace; use the main electrical panel.

Troubleshooting

First, determine if the fault lies with the furnace or the thermostat/wiring.

1. Furnace will not start: Set thermostat to highest setting. If 24V is present between C and W, the thermostat is closed, and the fault is in the furnace. Otherwise, the thermostat or wiring is the issue.
2. Furnace will not turn off: Set thermostat to lowest setting. If no 24V is present between C and W and the furnace continues running, the thermostat opened correctly, and the problem is in the furnace. Otherwise, the fault is in the thermostat or wiring.

Troubleshooting Table:

Sixty-Month Limited Warranty

Nortron warrants products against defects in materials or workmanship for sixty (60) months from the original purchase date. This warranty is the sole express warranty; implied warranties of merchantability or fitness for a particular purpose are limited to sixty months.

During the warranty period, Nortron will, at its option, repair or replace defective products or parts free of charge. The customer must ship the item prepaid to the factory or an authorized service center.

Exclusions: This warranty does not cover filters, separately sold furnace kits, ducts, or ducting accessories. It also excludes damage from misuse, negligence, accidents, improper maintenance or repair (unless by Nortron), or faulty/contrary installation.

Nortron is not responsible for transportation costs of repaired/replaced parts or reinstallation costs.

Limitations on implied warranty duration may vary by jurisdiction.

Nortron's obligation to repair or replace is the purchaser's sole remedy. Nortron is not liable for incidental, consequential, or special damages arising from product use or performance. Such limitations may not apply depending on jurisdiction.

This warranty grants specific legal rights, which may vary by province. It supersedes all prior warranties and applies only within Canada.

To qualify for warranty service, notify Nortron with the model number, part identification, and a description of the defect. Provide proof of original purchase date.