Instructions 7218-2 Page 3
To adjust regulator for this situation, first operate on main air only and follow instructions for nozzle-mix burners. Turn off main air (flame may go out), and turn on atomizing air. Remove gas diaphragm cover plug and turn spring adjusting plug clockwise until pilot relights burner and desired air/gas ratio is reached. Replace cover plug. Then adjust the regulator atomizing air plus main air at any firing rate. (If burner cannot be lighted on atomizing air only, adjust spring adjusting plug with main air at low fire setting.)
TROUBLE-SHOOTING, REGULATOR NOT RESPONSIVE
Make sure thread protection cap was removed from vent.
If impulse line is used, make sure it is not clogged, undersized, or inoperative due to bad installation. Disconnect impulse line from regulator vent and connect it to a gauge to observe impulse magnitude and changes; or use a tee in impulse line (per Figure 1), with gauge attached to third port. If premixer is used, test suction by shutting off gas supply and reading manometer attached to outlet test tap while air flows through mixer. If suction or impulse is satisfactory but regulator still is not respon-sive, shut off gas supply; remove outlet test plug, connect rubber tube to regulator vent and blow through tube. If pressure does not build up in the tube, gas diaphragm is ruptured and must be replaced.
TROUBLE-SHOOTING, FAILURE to CLOSE Individual steps to determine problem:
Make sure regulator has been adjusted to closed position at zero impulse (Step D4).
Remove air impulse connection to make sure there is no impulse during off period.
PLEASE REFER TO NORTH AMERICAN's "Practical Pointers" booklet for further details.
Attach manometer to 1⁄8 " outlet test tap to test for possible suction from furnace draft. To correct for this, cross-connect regulator vent to combustion chamber per Figure 3 or 4. Shut off gas supply. Remove body plug. Apply air impulse (about 16 osi) to the vent to raise regulator valve off seat: Wipe seat surfaces with cloth to remove pipe scale, dirt, pipe thread chips, or other foreign matter. Turn off air impulse and re-install body plug. Shut off gas supply. Remove body plug and 1⁄8 " inlet test tap plug. While pressing gently downward on regulator valve to hold it closed, blow through a rubber tube attached to inlet test tap. If backpressure dœs not build up, balancing diaphragm is ruptured and must be replaced.
Bonded valve, facing
Valve seat
Body plug
Inlet test tap plug
Pressure tube
Balancing diaphragm
Spring
Gas diaphragm
Vent on diaphragm cover (not shown)
Cover plug
Spring adjusting plug
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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