Burner Cleaning and Repair
Once the burner has been disassembled and inspected, it should be cleaned and repaired in order to return it to the manufacturer’s specifications.
As we mentioned earlier, the smallest port in a burner will plug first, therefore, you need to understand what type of burner is being repaired. A raw gas and Low NOx burner will have the smallest ports at the gas tips. A premix burner will have the smallest port at the fuel orifice.
Clean the gas tip with a drill tip in a T-bar handle. Power tools should never be used to clean the hole. An electric drill could potentially enlarge the hole causing one burner to get more fuel than the others.
The drill bit should be the same size as the original gas tip drilling. The size of the gas tip drillings will be shown on the original burner data sheet. Be aware that some burner tips could have several different hole sizes.
After reaming the holes, blow out the burner with air or steam to remove loose debris. Steam can also be used to check the burner tip flow pattern. If steam is used, the burner should be blown with air to remove moisture. After blowing out the burner tip, make sure that no other debris has become dislodged and is plugging the tip.
When cleaning the burner, check the gas tip for enlarged holes. If the holes are more than two drill sizes larger than the original design, replace the burner tip. Some gas tips are available in the storehouse while others must be ordered from the manufacturer. Always lubricate parts as they are being reassembled.
As we discussed earlier, always use the burner drawings to check burner tolerances and alignment. Some tolerances are as little as one eighth to one quarter of an inch. If the height of the gas tip is too short or too long, modify the riser. If alignment problems were found during the troubleshooting step, take corrective action. For some burners, it may be necessary to reassemble the burner at grade to check the alignment of the gas tips. Some facilities have made templates to check burner tip alignment outside the furnace.