kn series gas boiler installation & operating ... - Agencespl.com

Page 22KN INSTALLATION AND OPERATION INSTRUCTIONSCHECKING, ADJUSTMENT & OPERATIONFigure 17 - Pilot FlameSpark GapThe gap has to be measured and adjusted with theigniter removed from the boiler. Observe the trial forignition to confirm that the spark is strong andcontinuous. If not check and adjust the spark gap asshown in Figure 16.Figure 16 - Spark GapPilot AdjsutmentThe pilot pressure has been factory set at 1.5" andshouldn't need adjustment. To check the pilot pressureclose the manual main shut-off valve 2 and the pilot gasshut-off valve, Figure 14. Remove the 1/8" pipe plugfrom the pilot tee and connect a manometer having aminimum range of 6 in, 154 mm WC to it. the Open thepilot gas shut-off valve. With the unit powered generatea call for heat. When the prepurge is complete theignition/pilot trial will begin. At this point put theHoneywell 7895C test switch in the test position. Thecontrol will hold in the ignition/pilot sequence allowingyou to check the pressure.To adjust the pilot the following steps must betaken:1. Remove the pilot gas pressure regulator cap.2. Turn the pressure regulator adjustment screw clockwiseto increase the pressure and counterclockwiseto decrease it.3. Replace the pressure regulator adjustment screwcap.CAUTION: Never force the regulator adjustmentscrew beyond the stop limits or damage to theregulator will occur!Pilot flame UV signalBefore you check the pilot signal you need to make surethe polarity of the 120v supply to the ignition transformeris correct. To do this close the manual main shut-offvalve 2 (Figure 14) and the manual pilot shut-off valve.With the unit powered generate a call for heat. The boilerwill start to go through it start up sequence. During theignition/pilot sequence observe the lights on theHoneywell 7895C. The pilot light should come on but notthe flame light. If the flame light comes on along withthe pilot light, interrupt the call for heat and turn off themain power. Reverse the 120v supply leads to theHoneywell 652B ignition transformer and run this testagain. With this done the flame signal should bebetween 3vdc and 5vdc. Check the voltage on the testconnections of the Honeywell 7895C's amplifier with adc voltmeter.Main Burner CombustionThe fuel/mixture on full fire is not adjustable. TheCO 2 was checked at the factory and should beapproximately 8.5% to 8.8%. However if the CO 2 is wellout of this range something is wrong. Check if the endof the gas pipe is centered in the 2" x 5" air orifice inthe filter box. The end of the pipe should be centeredin and square to the opening, and it should be insertedby approximately 3/8". Also make sure the entire gastrain is secured tightly to its support arms.The fuel/air mixture on min or low fire is adjustable. Thismixture was set at the factory to match that of the fullfire. Therefore the CO 2 should be approximately thesame over the entire firing range.