Delta-T Charts

51 Points for servicing residential oil equipment

This should take approximately 1.5 - 2 hours

If you are not a qualified technician use these steps as a checklist only, to verify the preventive maintenance is being done properly.

1. Check the thermostats are level and have proper anticipator settings (if applicable) Electronic thermostats do not require leveling and do not have anticipator settings but usually have cycle rate menus. Verify the proper setting is selected.
2. Turn off power supply
3. Turn off oil supply
4. Check for any water leaks, duct leaks, oil leaks etc. repair if found.
5. If hot water system with diaphragm type expansion tanks - drop water pressure to "0" and check the air charge in the tank
6. Protect the floor from soot damage with floor covering of your choice
7. Gain access for cleaning of heat exchanger. Some units have side access plates, swing open doors or other types of access. They may be hidden under the jacket.
8. Brush down all heating surfaces If the unit has baffles, remove baffles, brush clean, brush flue ways and re-install baffles.
9. Re-install clean-out access plates, close doors etc. These access areas must be sealed. Most will have gaskets. If not seal with proper sealing material or new gaskets.
10. Carefully remove vent pipe. Caution - May be hot
11. Brush interior of vent pipe. Suggestion - have vacuum hose in one end of pipe to stop free particles from floating around while brushing.
12. Vacuum chimney base and top of boiler sections.
13. Reassemble vent pipe and if needed seal around smoke pipe at chimney base with proper material.
14. If equipment is supplied with a draft regulator, it must be level and plumb when vent pipe is reinstalled. Draft regulator should be 18" or more from boiler or furnace.
15. Check combustion chamber for debris. Vacuum if needed taking precaution not to damage the combustion chamber (Note: Not all equipment will have combustion chambers, but this area still needs to be cleaned)

16. Change oil filter
17. Inspect/replace fuel pump strainer (always use a new gasket)
18. Blow oil line with Co2 cartridge if needed (Do not blow lines to underground tanks or tiger loops)
19. Remove, inspect, and clean firing assembly, check porcelains for cracks and make any electrode adjustments. Check all head adjustments are to manufacturers specs.
20. Replace nozzle with proper gph, spray angle and flame pattern per manufactures specifications *
21. Reinstall firing assembly (do not connect high pressure line at this time)
22. Clean burner fan blades and burner housing if needed.
23. Double check everything is back to its normal operating condition except the high-pressure line
24. Remove thermostat wires from thermostat wire connections at boiler or furnace

25. Place jumpers on thermostat wire connections
26. Open oil supply and bleed all air from oil line, filter, and fuel pump
27. Have a container on high pressure line to collect some fuel oil (This is done to protect filter on nozzle from contamination due to cleaning fuel system)
28. Change air filters if warm air furnace
29. Inspect/replace/adjust blower belt if applicableClean blower wheel blades if needed.
30. Turn on power supply and time burner safety shutdown. Burner should shut down in the amount of time the primary control specifies on the rating label
31. Turn off power supply
32. Re-connect high pressure line
33. Connect pressure gauge and vacuum gauge **
34. Turn power supply on and reset primary control
35. Allow burner to run about 10 minutes
36. Compare pressure and vacuum readings to manufacturer specs. Most manufacturers are operating at 140 psi or greater on newer equipment. **
37. During this time, check all control settings for proper adjustment per manufactures spec.'s
38. Oil all motors where applicable. Newer equipment may have permanently sealed bearings
39. Locate the sampling hole in the vent pipe. This should be within 1 pipe diameter of the appliance and a minimum of 2 pipe diameters before the draft regulator.
40. All tests will be taken at this test point except a draft test which will be required to be taken over fire on negative draft units and in the vent pipe or positive draft units. Today manufactures will normally supply this port in fire observation door. If older equipment you may be required to drill it in the observation port. You will be required to seal this hole for over fire readings when completed.
41. Observe over fire draft reading is within manufacturer spec.'s. For negative draft boilers it is normally -0. 02. When taking this reading, there should not be any air leaking around your sampling tube.
42. Perform a smoke spot test at the vent pipe test hole.
43. Perform a Co2 reading. Adjust to manufacturers specs. Normally 10% to 12.5%
44. Perform a stack temp reading. Compare all test results with manufacturers specs ***
45. Check all safety controls for proper operation
46. Remove jumpers from thermostat connections
47. Reinstall thermostat wires
48. Check for oil leaks and that everything is reinstalled and sealed properly.
49. Remove floor covering carefully
50. Wipe down boiler jacket removing dust and dirty handprints.
51. Complete all paperwork and thank customer on way out.

* Older equipment will normally operate at 100 psi fuel pressure. With many manufacturers operating with increased pump pressures 140 psi or greater the maximum firing rate on the rating plate may not be the actual nozzle size. See increased pump pressure and nozzle sizing charts from nozzle manufacturers
** Normally a vacuum test is only required if the lines are overhead or there is an underground fuel tank. Above ground tanks and basement tanks where the tank and appliance are on the same level, or, the tank is higher than the appliance, normally will not require a fuel pump vacuum test.
*** The over fire draft test will not be required on pressure fired equipment. Most residential equipment is natural vent and will operate on a negative draft. Some equipment today is operating in a positive drat condition. This would include direct vent equipment; not to be confused with power vented equipment.

Disclaimer: The information found on this website is for informational purposes only. All preventive maintenance, service, installations should be reviewed on a per job situation. Any work performed on your heating system should be performed by qualified and experienced personnel only. Comfort-Calc or its personnel accepts no responsibility for improper information, application, damage to property or bodily injury for applied information found on this website.