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NORA Oilheat Technicians Manual

Horizontal Flue Connection Vertical Flue Connection pipe near the boiler or furnace outlet (the breech), see Figure 7-9. With electronic testers, the hole may have to be larger to accommodate the probe. The hole should not be in an elbow. With the older test equipment, you will want to drill two holes to speed up the process. They should both be as close to the breeching (the place where the flue pipe connects to the furnace, boiler or water heater) as possible. The holes should be at least 6" from the draft regulator on the furnace or boiler side of the regulator. There is no need to plug the holes in the stack, but we do suggest that you insert self-threading screws or snap caps in the holes. You will also need a hole in the fire or observation door over the burner. Some new units do not have a door over the burner. If this is the case, check to see if the manufacturer has provided a special port for you to do your over-fire test. See Figure 7-6. Chapter 7 Combustion Chapter 7—Combustion 7-11 Chimney Note A Note B Flue Pipe Draft Regulator Location for Sampling Hole Oilburner used for many years and can produce reliable results if used and maintained properly. The problem is, testing with the older manual equipment is time-consuming and only gives you a fuzzy snapshot of the burner performance. (Each squeeze of a wet kit bulb represents a different snapshot of the flue gas. A manual test blends all those snapshots together into one reading.) The digital equipment is much quicker, and does efficiency calculations automatically. The best feature of the digital equipment is that they sample continuously, like using a video camera, so you can see the results change as you make the adjustments. It gives you a much better idea of what is going on. Holes for testing Measurements are taken through a threeeighths (3/8) inch hole drilled in the flue Figure 7-9: Measuring for combustion efficiency A. Locate hole at least one flue pipe diameter on the furnace or boiler side of draft control. B. Ideally, hole should be at least two flue pipe diameters from breeching or elbow. Location for Sampling Hole Note B Note A Breeching


NORA Oilheat Technicians Manual
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