Sheet 6131-5P Page 2
PREMIX PILOT ASSEMBLY AND ADJUSTING PROCEDURE
The following adjustment procedure is recommended:
An alternate method for adjusting the premix section of the mixer for correct on-ratio firing is to use the following procedure with an 8666 Pilot Testip:
1. Install a manometer at Item "A".
2. Turn the burner on manual purge and measure the combustion air pressure at the port on the tee on which the manometer has been installed. This pressure should read at least 4"wc.
(a) Remove pipe plug from top of mixer and connect pilot testip.
(b) Firmly bottom mixer valve (Item "B") and back out four (4) complete turns.
NOTE : When adjusting an 11-7478 Pilot Assembly, the spring in Item #11 (7344-01) should be completely relaxed.
(c) Close raw gas valve (Item "C").
(d) Turn on pilot and adjust mixer valve (Item "B") by turning slowly first one direction and then the other until pilot testip and pilot light. (e) Observe flame on pilot testip. Base of flame should be se- curely seated inside testip. Adjust mixer valve to make sure that base of flame is securely seated in pilot tip.
3. Remove the manometer.
4. Remove cap and screw in the gas mixer valve (Item "B") until it bottoms and is closed. The mixer valve is then backed out four (4) complete turns. The raw gas valve (Item "C") located at the back of the mixer should be closed. 5. Start burner and allow pilot to light. Observe the pilot flame. This flame will be approximately 3-4" long and should have a sharp, blue cone appearance; it should not be fluttery. If the flame appearance is not sharp, turn the mixer valve 1 ¼ turns either way to achieve this appearance. Replace cap. 6. At this point, the burner will go off on "flame failure." The burner programmer is then reset and the burner turned on. At this time, the raw gas valve (Item "C") between the mixer and the upstream gas pressure is opened so that pressure gauge reads no greater than 1 ¾ psi. The programmer will then recycle to the pilot period and the pilot flame should be approximately 9-10" long. Move the programmer test switch to the "test" position so the pilot is held in the pilot cycle. The flame signal strength should now be observed. This should be a steady signal of 2 microamps with a Honeywell programmer. With Fireye, refer to the appropriate Fireye bulletin for required signal strength. Return test switch to "Normal" position.
(f) Turn off pilot. Remove testip and reinstall pipe plug. Pilot should now be on-ratio. Proceed as instructed in Item #6.
(g) Burner should be recycled a number of times to prove pilot reliability.
7. The burner should be recycled a number of times to prove pilot reliability.
WARNING: Situations dangerous to personnel and property may exist with the operation and maintenance of any combustion equipment. The presence of fuels, oxidants, hot and cold combustion products, hot surfaces, electrical power in control and ignition circuits, etc., are inherent with any combustion application. Components in combustion systems may exceed 160°F (71°C) surface temperatures and present hot surface contact hazard. Fives North American Combustion, Inc. suggests the use of combustion systems that are in compliance with all Safety Codes, Standards, Regulations and Directives; and care in operation.
CONTACT fna.sales@fivesgroup.com T +1 800 626 3477 - F +1 216 373 4237
Fives North American Combustion, Inc. 4455 East 71st Street - Cleveland, OH 44105 - USA www.fivesgroup.com
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