Energy Tech Laboratories Modular Direct Fired Heaters Sequence of Operation, Flame Safety Control

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DC Voltage
0 to 5 VDC
6 to 11 VDC
12 to 18 VDC
Flame Status
No Flame
Weak Flame
Strong Flame

Sequence of Operation

The direct-fired heater is most easily understood when broken down into smaller individual systems. There are two main systems, a make-up air fan and a heater. The make-up air fan consists of a blower and motor. The heater may be further broken down into two control systems, the Flame Safety Control (FSC) and the Modulating Gas System (MGS). The burner mixes air with the gas (Natural or LP) which heats the air.

Flame Safety Control

The first system to understand is the Flame Safety Control. The FSC is there only to monitor the flame, NOT to control temperature. The FSC uses a flame rectification sensor mounted on the pilot assembly to detect the presence of flame in the burner. Flame strength and presence can be measured at the FSC by reading the rectified flame signal. This is done by removing the FSC cover and using a DC voltage meter in the test jacks. Flame is present when the DC voltage reads between 6 and 18 VDC. Ideal flame intensity produces a signal of 12 VDC or greater. The FSC is also wired into an airflow switch, which tells it whether there is proper airflow through the unit (not just any airflow, but proper airflow). Proper airflow occurs when there is a

.15 in. w.c. to .65 in. w.c. differential pressure drop across the burner. When the airflow through the heater produces a pressure drop in this range, the FSC indicates so by illuminating the AIRFLOW LED. The FSC controls the opening of the redundant solenoid gas valves and the operation of the spark igniter to initiate a pilot flame upon start-up.

Flame Safety Controller

DC Flame Signal

The OPR CTRL LED indicates that there is power to the FSC. Next, the AIRFLOW LED will come on if there is proper airflow through the

unit. Third, the unit will pause to purge any gasses or combustible vapors before attempting flame ignition. Then, there is a Pilot Trial For Ignition (PTFI) and the PTFI LED comes on. During PTFI, the FSC opens the pilot gas valve and allows gas to flow to the pilot assembly. At the same moment, the spark igniter is started, causing the spark to ignite the pilot gas. When the flamerod sensor detects the flame, it turns on the FLAME LED, turns off the PTFI LED, and powers the modulating gas system. This is the normal operating mode. The FSC continues to monitor the flame and airflow. Once this occurs, the unit is in a main flame cycle and thus powers the main gas valve and the modulating gas system. This is the normal operating mode. The FSC continues to monitor the flame and airflow. The last LED on the FSC is the ALARM LED. This will turn on when the FSC determines an unsafe condition has occurred, and will not allow the unit to recycle for heat until it has been properly reset. Anytime the FSC has gone into “Alarm” mode, the problem must be diagnosed and corrected to avoid future lockouts after resetting. To begin troubleshooting, or to reset the FSC, shut down power to the heater and restart the heater. This will clear the alarm from the flame safety.

Air Flow Switch

Air Flow Switch

 

There are both high and low airflow switches contained within one housing measuring the pressure drop across the burner. This is to insure that there is proper airflow (.15 in. w.c. to .65 in. w.c.) across the burner and proper combustion at all times. Both switches are wired in series and have single pole double throw (one common contact, one normally open contact, and one normally closed contact) switches that are ‘switched’ by air pressure. There are two airflow tubes in the heater, located near the burner and profile plate assembly (profile plates surround the burner and control air into the burner section). In the case of clogged filters, blocked intake, excessive duct static pressure, or a broken belt, the correct burner differential pressure may not be achieved, not allowing the low

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Contents Installation, Operation, and Maintenance Manual Table of Contents Warranty Site Preparation InstallationAssembly MechanicalRecommended Supply Ductwork Sizes Roof Mount Installation Installation with Exhaust FanPage Gas Gas Connection SizesGas Pressure Table Copper Wire Ampacity ElectricalMotorized Intake Damper Fan to Building Wiring Connection Remote Control PanelStart Up OperationMain Burner Adjustment Heater Start Up Summary Yes Adjust pilot flame Lock unit into High fireSetscrew Torque Final Start Up ProcedureMaximum RPM and HP Chart Pulley Adjustment Illustration Pulley Adjustment10 20 IN. Blower Pulley Combination ChartSequence of Operation Flame Safety ControlFlame Safety Controller DC Flame Signal Air Flow SwitchMaxitrol Amplifier High Temperature Limit Modulating Gas SystemOperation Summary Optional Remote Panel Circuit Blower SwitchComponents Remote Panel Option Airflow Troubleshooting Chart TroubleshootingProper Spark Gap Burner Troubleshooting ChartLight Indication Condition Possible Cause Remote Panel Troubleshooting ChartNothing Happens Troubleshooting FlowchartsFlame Safety Service Guide Flame Safety Service Guide General Maintenance MaintenanceYearly Filter Quantity ChartWeeks after startup Every 3 monthsJob Information Start-Up and Maintenance DocumentationMaintenance Record Factory Service Department

Modular Direct Fired Heaters specifications

Energy Tech Laboratories has established itself as a leader in the development of innovative modular direct fired heaters, designed to meet the evolving demands of industries that require efficient and effective heating solutions. These heaters are engineered to offer versatility, reliability, and enhanced performance, making them suitable for a broad range of applications.

One of the standout features of Energy Tech Laboratories' modular direct fired heaters is their modular design. This allows for easy scalability and customization, enabling users to adjust the heating capacity according to specific requirements. The modular aspect also facilitates straightforward installation and maintenance, reducing downtime and operational costs.

The heaters utilize advanced combustion technology that optimizes fuel consumption while minimizing emissions. This ensures not only a cost-effective operation but also compliance with environmental regulations. By combining high thermal efficiency with a low carbon footprint, these heaters contribute to sustainable energy practices.

In addition to their efficient combustion system, Energy Tech Laboratories incorporates state-of-the-art control technologies in their heaters. These systems allow for precise temperature regulation and can be integrated with existing Building Management Systems (BMS) for enhanced monitoring and control. Users can benefit from real-time data and analytics, which help in diagnosing potential issues and optimizing performance.

Durability is another characteristic that sets these heaters apart. Constructed with high-quality materials, they are designed to withstand harsh industrial conditions, ensuring a long service life. The robust design minimizes the likelihood of breakdowns, which is critical for industries that rely on continuous operation.

Moreover, Energy Tech Laboratories emphasizes safety in the design of their modular direct fired heaters. Equipped with multiple safety features such as flame detection, gas leak detection, and emergency shutdown systems, these heaters are built to operate within stringent safety standards.

The flexibility of these heaters makes them suitable for various sectors, including oil and gas, manufacturing, and construction. Their ability to provide direct heat quickly and efficiently makes them ideal for processes that require consistent temperature control.

In conclusion, Energy Tech Laboratories' modular direct fired heaters represent an advanced solution for today’s energy needs. With their modular design, advanced combustion technologies, and focus on safety and durability, these heaters stand out as a preferred choice for industries seeking reliable and efficient heating solutions. Their commitment to innovation and sustainability positions them as a front-runner in the energy technology sector.
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