trunk ducts. These systems may require modification to provide some resistance to the airflow to prevent over-amping of the direct drive blower motor. Selecting a lower blower speed may correct this problem.

Direct drive blower speeds are adjusted by changing the "hot" wires to the motor winding connections. Please refer to wiring diagram in Appendix B or the wiring diagram label affixed to the furnace. THE NEUTRAL WIRE (normally the white wire) IS NEVER MOVED TO ADJUST THE BLOWER SPEED.

DO NOT CONNECT POWER LEADS BETWEEN MOTOR SPEEDS. THE NEUTRAL WIRE MUST ALWAYS BE CONNECTED TO THE MOTOR'S DESIGNATED NEUTRAL TERMINAL.

It is possible and acceptable to use a single blower speed for both heating and cooling modes. The simplest method to connect the wiring from both modes is to use a "piggy-back connector" accommodating both wires on a single motor tap. It is also acceptable to connect the selected motor speed with a pigtail joined to both heating and cooling speed wires with a wire nut. As a safety

precaution against accidental disconnection of the wires by vibration, it is advisable to secure the wire nut and wires with a few wraps of electricians tape.

If the joining of the blower speed wiring is done in the furnace junction

box, tape off both ends of the unused wire.

DISCONNECT THE POWER SUPPLY TO THE FURNACE BEFORE OPENING THE BLOWER ACCESS DOOR TO SERVICE THE AIR FILTER, FAN AND MOTOR. FAILURE TO SHUT OFF POWER COULD ALLOW

THE BLOWER TO START UNEXPECTEDLY, CREATING A RISK OF DEATH OR PERSONAL INJURY.

Do not use the blower speed wires as a source of power to accessories as electronic air cleaners and humidifier transformers. The unused motor taps auto-generate sufficiently high voltages to damage accessory equipment. Use the terminals provided on the electronic fan timer.

Do not start the burner or blower fan unless the blower access door is securely in place.

Additional ST9103 Fan Timer Control information is in Appendix A, Tables, and in Appendix B, Wiring Diagrams.

HUMIDIFIER

A humidifier is an optional accessory available through most heating supplies outlets. Installation should be carried out in accordance with the humidifier manufacturer's installation instructions. Water or water droplets from the humidifier should not be allowed to come

into contact with the furnace heat exchanger. Do not use direct drive motor connections as a source of power for 120 VAC humidifiers and humidifier transformers.

OIL BURNER

The oil burner must align properly with the cerafelt fiber chamber (firepot). The cerafelt fiber chamber is initially quite soft, but hardens and becomes quite brittle after the first firing. The firepot is held in place by a retaining bracket; however, it is possible for the firepot to shift if subjected to rough handling during transit.

BEFORE OPERATING THE

FURNACE CHECK BURNER ALIGNMENT WITH COMBUSTION CHAMBER. THE END CONE OF THE AIR TUBE MUST BE CENTRED TO

THE ACCOMODATING RING PROVIDED IN THE DESIGN OF THE COMBUSTION CHAMBER. ADJUST ALIGNMENT AS NECESSARY BEFORE THE FIRST FIRING.

OIL BURNER NOZZLES

WML-C AND MPL-B furnaces are certified for multiple firing rates, ranging from approximately 58,000 to 85,600 BTU/hr. on the WML-C and 85,500 to 123,000 BTU/Hr. on the MPL-B By changing the oil burner nozzle within the specific model range, and temperature rise, the furnace may be fired at an ideal rate for a wide range of structures.

Figure 4: Horizontal Smoke Test Port Location

Figure 5: Vertical Smoke Test Port Location

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30318 R4 9/9/2005

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Field Controls MPL-B, WML-C manual Humidifier, OIL Burner
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MPL-B, WML-C specifications

Field Controls, a leader in the HVAC industry, offers innovative solutions for air quality and equipment efficiency. Among their range of products, the WML-C and MPL-B series stand out for their remarkable features and advanced technologies, catering to the unique needs of both residential and commercial applications.

The WML-C series is designed for optimal ventilation and air quality management. It integrates seamlessly with existing HVAC systems, providing crucial airflow control and ensuring that indoor environments maintain optimal levels of fresh air. One of its key features is the variable speed fan technology, which adjusts according to the desired airflow rate, thereby enhancing energy efficiency. This not only reduces operational costs but also contributes to a more sustainable environment.

The MPL-B series, on the other hand, focuses on purification and filtration. Equipped with advanced media filters, it effectively captures airborne particles, allergens, and pollutants, which is essential for maintaining clean indoor air. The MPL-B series utilizes a multi-stage filtration system that includes HEPA filters, ensuring that the air circulated within spaces meets high standards for cleanliness and safety.

Both the WML-C and MPL-B models utilize smart technology for enhanced control and monitoring. With integrated sensors, users can receive real-time data on air quality, humidity levels, and system performance, allowing for proactive management and maintenance. Additionally, they are compatible with various building management systems, enabling integration into larger infrastructure for comprehensive environmental control.

Durability and reliability are paramount in the design of these units. Built from high-quality materials, both the WML-C and MPL-B are engineered to withstand rigorous usage and varying environmental conditions. Their compact designs allow for flexible installation options, making them suitable for a wide range of settings.

In summary, Field Controls’ WML-C and MPL-B series offer cutting-edge solutions for air quality and HVAC efficiency. With innovative features such as variable speed technology, multi-stage filtration, and smart monitoring capabilities, these systems are ideal for enhancing indoor environments while maintaining energy efficiency and sustainability. They not only meet but exceed the expectations of modern HVAC requirements, making them a valuable investment for any property owner.
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