National Products BW3 - Manual (Page 17)

MAINTAINING BOILER
PROCEDURE 1—BURNERS
A visual check of pilot and main burner flames should be made at least once each year, preferably at beginning of heating season. See Checking
and Adjusting section and Fig. 9, 11, and 12. Main burner flame should form a sharp blue cone with no yellow.
PROCEDURE 2—RELIEF VALVE
This valve should open automatically when system pressure exceeds pressure rating (usually 30 psi) of relief valve. Should it ever fail to open under
this condition, shut down system. Drain system until pressure is reduced below relief valve pressure rating. If valve discharge occurs or if valve
fails to open as described above, contact an authorized contractor or qualified service technician to replace relief valve and inspect heating system
to determine the cause, as this may indicate an equipment malfunction.
This valve should be tested every month during periods of boiler operation, and at the beginning and end of any extended non-service period. Prior
to testing, make certain discharge pipe is properly connected to valve outlet and arranged so as to contain and safely dispose of boiler discharge.
Test at normal system operating pressure. Hold trip lever fully open for at least 5 sec in order to flush free any sediment that may lodge on valve
seat, then permit valve to snap shut.
PROCEDURE 3—EXPANSION TANK
As previously noted, this tank may become waterlogged or may receive an excess of air. Frequent automatic opening of relief valve indicates
waterlogging. A high boiler temperature accompanied by unusually low radiation unit temperature (and "knocking") indicates excess air in tank.
To correct either condition, close valve between boiler and tank. Drain tank until it is empty. Check all tank plugs and fittings. Tighten as necessary.
Open valve between boiler and tank. Water will rise to normal height in tank if automatic fill valve is installed, otherwise, manually refill system.
PROCEDURE 4—BOILER FLUE PASSAGES
Under normal operating conditions with burners properly adjusted, it should not be necessary to clean boiler flue gas passages. However, to assure
trouble-free operation, we recommend that flue passages, burner adjustment, and operation of controls be checked ONCE EACH YEAR by a
competent service technician.
BEFORE THE START OF EACH SEASON (or whenever system has been shut down for some time), recheck whole system for leaks and recheck
boiler and vent pipe for leaks. Replace or patch any boiler seals that are faulty.
PROCEDURE 5—VENT PIPE
The venting of this unit is very important. Piping should be checked at least once a month. If vent piping shows any signs of leaking, replace it
immediately.
PROCEDURE 6—WATER SYSTEM
If system is to remain out of service during freezing weather, always DRAIN IT completely. Water left in to freeze will crack pipes and/or boiler.
PROCEDURE 7—CLEANING BOILER AND BURNERS
Flue passages between sections should be examined yearly and cleaned if necessary. To clean:
1. Remove burners, pilot, and vent pipe.
2. Remove top and front jacket panels.
3. Split silicone seal on flue collector and cleanout plates with a razor knife.
4. Remove flue collector.
5. Remove cleanout plates by tapping upwards on bottom of plate with a hammer.
6. Remove loose silicone sealant from sections, flue collector, and cleanout plates.
7. Clean passageways between sections with a flexible handle wire brush and a straightened out wire coat hanger. Remove dirt from bottom
of boiler and between sections by vacuuming.
8. Make sure all flame ports in burners are open and clear. Shake out or blow out all loose dirt in burners.
9. Reassemble all parts.
10. Seal flue collector and cleanout plates to sections with 400°F RTV silicone sealant or equivalent.
11. Reseal seams between adjacent sections as necessary. All joints MUST be airtight.
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Fig. 11—Main Burner Flame
A99182
OUTER MANTEL
SHARP INNER CONES
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