Water heater having raw fuel jet pilot and associated burner clogging detection apparatus

A method of creating hot combustion products in the combustion chamber of a fuel-fired heating appliance, said method comprising the steps of:

• positioning a pilot flame stabilizing structure within said combustion chamber;
• positioning a main fuel burner within said combustion chamber;
• creating within said combustion chamber a fuel jet which impinges upon said pilot flame stabilizing structure;
• mixing air from outside said combustion chamber with said fuel jet to form therewith a fuel/air mixture;
• and
• igniting said fuel/air mixture to create a pilot flame extending outwardly from said pilot flame stabilizing structure and useable to ignite a fuel/air mixture subsequently supplied to said main fuel burner.

A fuel-fired heating appliance comprising:

• a combustion chamber thermally communicatable with a fluid to be heated;
• a main burner disposed within said combustion chamber;
• and
• a pilot burner structure disposed within said combustion chamber for igniting said main burner and including:
• a flame stabilizing structure disposed within said combustion structure;
• fuel delivery apparatus operable to receive fuel from a source thereof and discharge the received fuel in the form of a fuel jet that impinges against said flame stabilizing structure;
• and
• air delivery apparatus through which combustion air from outside said combustion chamber is flowable through an enclosed flow path to adjacent the discharged fuel jet to form therewith a fuel/air mixture ignitable to create a pilot flame extending outwardly from said flame stabilizing structure.

Fuel combustion apparatus comprising:

• a hollow burner body having an outer wall portion with fuel/air discharge openings therein;
• a fuel delivery tube extending into the interior of said burner body, said fuel delivery tube being operative to receive pressurized fuel from a source thereof and discharge from an opening therein a fuel jet which impinges against the interior surface of said outer wall portion;
• and
• an air delivery conduit extending into the interior of said burner body and operative to deliver combustion air from a source thereof to the discharged fuel jet to form therewith a fuel/air mixture passing outwardly through discharge openings in a section of said outer wall portion and being ignitable to form a pilot flame extending outwardly from said outer wall portion.