Supplement 4988-4 Page 2
START-UP INSTRUCTIONS 1. Set all safety limit switches to the correct settings (burner air flow, low and high gas pressure, safe high temperature, etc.). Shut all gas valves. 2. Remove all papers, rags and other obstructing material from the vicinity of the burner air inlet. Start the duct circulating fan. 3. With the duct fan in operation and the burner motor off, read the static duct pressure using the tap on the main gas connection of the burner. This pressure will be useful in steps 13 and 15. 4. Bump the burner blower motor starter and check for correct blower rotation (from the air inlet side, the rotation must be CCW). Correct wiring if necessary and then start the blower motor. 5. With the gas valve(s) still closed, and the duct air circulating fan and the burner blower in operation, use a manometer to read the differential pressure between the gas pressure tap on the main gas connection and the air pressure tap on the burner housing. This pressure should be 1"wc for neutral pressure installations (slightly more for suction side instal- lations and less for pressure side installations). Adjust the blower inlet air disc to obtain a dofferential of 1"w.c. 6. Stroke the gas control valve and motor so that when the motor is in the low fire position the gas valve is 1⁄8 open, and with the motor in the high fire position the gas valve is full open. 7. Open the manual low fire and main gas shutoff valves. Remove the screw on the top of the low fire adjusting valve handle and turn the adjusting screw inside CW until it is fully closed. Then turn the screw three full turns CCW. 8. Make the initial main gas regulator adjustment by setting outlet pressure approximately 3"w.c. Compensate setting for piping losses and duct pressure. 9. Energize the flame supervisory system. If all of the limit switches are satisfied, the purge cycle will start. When the purge is complete, the burner will begin trial for ignition. 10. Press the start button on the burner control panel to ener- gize the ignition transformer and the low fire solenoid valve. Adjust the screw in the low fire gas valve until you achieve a satisfactory low fire flame. If the low fire flame is not es- tablished within the required time, the flame supervision will close the low fire solenoid valve. You will then have to press the flame supervisiory reset switch and repeat the adjusting procedure until the flame is established.
11. When low fire lights and is proven by the flame detector (flame rod or UV scanner), the safety shutoff valves will be- come energized. 12. Once the safety shutoff valves open, the main flame will ignite. Use the temperature controller to hold the burner at low fire and then check the outlet pressure of the main gas regulator as set in step 8. 13. With an interrupted low fire system, the timer will de-energize the low fire solenoid a few seconds after the safety shutoff valves are opened. The flame supervisory system will then monitor the main flame only. 14. Using the temperature controller, run burner to high fire. When the system is at normal operating temperature, make the final gas regulator outlet pressure setting if the pressure has drifted. Either readjust the regulator to maintain 3"w.c. p gas pressure between burner and duct, or if the gas train is equipped with an 8697 metering orifice, adjust regulator to provide correct p for the burner rating. 15. Run the burner controller back to low fire and check the flame. If necessary, readjust the linkage until the flame pulls back into the burner.
16. Repeat steps 14 and 15 as necessary.
17. When the system has reached operating temperature, it may also prove necessary to readjust the blower inlet air disc as set in step 5. If a change is made, restart the burner when the system is cold. The burner will usually operate satisfacto- rily at both temperature extremes with a 1"w.c. P, but if not, a compromise setting can be found that will provide good performance at all temperatures. 18. With the burner operating, check the operation of the flame supervision and all safety limits one at a time. Check the flame supervisory system by shutting the downstream main gas shutoff valve (and the manual low fire gas valve if oper- ating intermittently). Check the operation of the safety limits by manually actuating each switch. The burner must shut down on each limit.
Made with FlippingBook flipbook maker