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NORA Oilheat Technicians Manual

Chapter 4 Fuel Units and Oil Valves Figure 4-18: Hand pump 4-14 Fuel Units and Oil Valves chamber bolts, pump seal leak, or the pump leaking at ports, or it could be the fittings up to the shut off valve. Recheck the gasket, plugs and fittings and try again. If you are sure everything is tight, the leak may be in the unit itself, and you will have to replace it. 10. If the vacuum holds, you know that the fuel unit and all the piping up to the shut off valve are OK. Now it is time to open the shut off valve near the pump, and if there is one, shut off the valve at the tank, or at the wall where the suction line enters the building. Do the test again. If the vacuum holds, you know the leak is between the valve and the tank. Warning: We used to check for leaks using the pressure test method. The problem with pressurizing oil lines is it usually creates more leaks than it finds. We strongly urge you to never pressurize oil lines or tanks. This includes blowing out the lines with a CO2 cartridge; instead use a hand pump to suck the line clear, Figure 4-18. Visual test or sight glass test for air in oil lines When you detect air in oil lines, you must find the source of the leak. The first step is to tighten all fittings in the suction line and tighten unused inlet port plugs in the pump. Be sure there are no compression fittings in the oil lines. Then check the filter cover and gaskets, making sure there is a good gasket on the pump cover. If none of this eliminates the air, you must start searching for the source of the leak. To confirm that there is a leak and to pinpoint the source, use the Visual Test or Sight Glass Method. Vacuum test If the operating vacuum is less than the calculated figure, you have a leak to find. First determine if the pump or fittings up to the pump shut off valve are leaking by performing a Vacuum Test. 1. Fill the fuel unit with oil. 2. Shut off the valve closest to the pump. If there is no valve, disconnect the supply line at the fuel unit. 3. On a two pipe system, disconnect the return line and place an open container below the return port of the fuel unit. 4. If the system is single pipe, connect a bleed hose to the bleeder port and the opposite end in an open container. 5. Install your vacuum gauge in the alternate inlet port on the pump. (If there was no shut off and you have disconnected the suction line, install the gauge in the inlet port.) 6. Start the burner and open the bleed port. Run it until a vacuum of 15" is reached. On a single pipe system you must open the bleed port while the burner is running to raise the vacuum. 7. Once the vacuum is reached, close the bleed port. (You may need to jumper the FF terminals on the primary control after burner start up to get the burner running long enough to reach the vacuum reading.) 8. While the burner is running and you have reached the required vacuum, on the two pipe system, plug the return port and turn the burner off. On a single pipe, close the bleed port and turn the burner off. 9. Check the vacuum reading after shut down. The vacuum should hold for at least five minutes. If the vacuum does not hold steady, you could have a leak in the pump, a leak in strainer chamber gasket, loosened strainer


NORA Oilheat Technicians Manual
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