2.0Control System Requirements
Turndown Method | Input is normally controlled by a motorized butterfly valve in the gas line to the |
| burner. |
Regulator Loading Lines | Connect the top diaphragm chambers of the main gas and pilot gas regulators to the |
| duct approximately 10" downstream of the burner. This will allow the regulators to |
| maintain a constant supply pressure to the burner regardless of varying pressures in |
| the duct. |
Piloting | Pilot gas flow is adjusted as shown in Figure 6. |
Ignition | Ignition voltage should be 6000 VAC. |
Check Valve | See Figure 3. At high fire, the gas pressure at the burner inlet is higher than the air pressure, and |
| the check valve is closed. At low fire, gas pressure falls below the air pressure, and the check |
| valve opens, permitting a small amount of air to mix with the gas. This premix at low fire stabilizes |
| the flame and helps distribute the flame evenly down the length of the burner. |
wWarning
Do not install any valve or controlling device in the gas line between the burner and the check valve tee, Figure 3. Because this section of the gas line carries a partial pemix at low fire, it is possible under unusual condi- tions for the flame to travel back through the pipe to the tee. Devices in- stalled in this section may be damaged and may melt, releasing gas to the atmosphere and causing fires or explosions.
Pressure Switch Connection See Figure 4 for typical connection of combustion air and circulating fan limit switches.
Limit Controls &Safety Equipment Limit controls and safety equipment should comply with current NFPA Stan- dards* 86 and 86C, and all applicable local codes and/or standards.
*Available from: |
|
National Fire Protection Association | American National Standard Inst. |
Batterymarch Park | 1430 Broadway |
Quincy, MA 02269 | New York, New York 10018 |
Figure | Figure | ||
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| Blower | |
WARNING! |
| Pressure Switch | |
|
| ||
Do Not Install Any Valves Here! |
| P | |
See Section 2.0 | Tube at | ||
Lo Hi Burner Air Tap | |||
Tee | |||
Blower Inlet | |||
|
| See Figure 7 | |
Process Air |
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| |
Gas Inlet |
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| |
Manifold |
|
| |
Check Valve Opens When
Gas Inlet Pressure Is at Low Fire
|
| P |
|
Tube Points | Hi | Lo | Tube Points |
Upstream | Circulating Air | Downstream | |
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| ||
| Pressure Switch |
| |
4 | Eclipse AirHeat v1.0 - Installation Guide No. 140, 11/4/03 |
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