Re Williams 3003622 Heater Please advise how to ignite pilot light.

See if it visually the same as what you have. All parts for yours are obsolete.

Williams Furnace Company P322398 Pilot Generator ...

https://williamsfurnace.parts > williams-furnace-compan...
Natural Gas Model numbers include 1403822, 2003822 and 3003822, and can be used with all altitude options. Click here to download the replacement parts lists ...

US$65.55 · ‎In stock

https://www.searspartsdirect.com/model/ydhrgebuqn-001203/williams-3003622-wall-heater-parts

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That hole should only be a problem, if a strong draft comes thru and blows the pilot out. But that hole may also be for match lighting the pilot in an emergency. The older models like yours, had that feature. Check it closely, before you decide to block off the hole.

Hope this helped you.

clean pliot first should be a strong flame blue in colour , if this is done and it still goes out the it pionts to the thermocouple

Try jumping out the thermostat (red and white wires) that run to the thermostat these tell the heater to come on. Jump them together if you have heat it is the thermostat, if no heat it is the furnace. Should it be the furnace I would first check the thermocouple or some manufacturers call it a flame generator. Clean this with steel wool and position it in the top center area of the flame as this is the hottest part of the flame. Good luck

I'm having the same exact problem... At first we thought was the vent... but the way the flames goes out... it seems that there is "not enough oxygen" more than "blown out by the wind"... right after both main & pilot goes out, I can't even light any external flame inside the chamber... and it doesn't feel like the outside cold air coming in... it just feel like there is some sort of gas in the chamber that's so strong, it prevents flame... and the only thing I can think of is that it doesn't have enough oxygen, but too much natural gas, and flame can't sustain.

Instructions for lighting the pilot can be found on page 10 of this Installation Manual.
Here is link on How to Light the Pilot on a Water Heater. I realize this is not a water heater you are working on, but the setup is very similiar the link has a couple of videos that you might find helpful. :-)

THE flame from the pilot should shoot past the thermo-couple and heat this up and make a small amount of mili- amps to prove the pilot light is lit. ..So if the flame doesn,t go past the thermo-couple it won, make mili-amps or its tme to change out the thermo-couple, They only cost lest than $8:00 and you can change it!

yes clear the ice and clean the pilot assembly sounds like the flame is being retarded by a dirty pilot orifice

openthe inspection cover turn on and press ignition switch if this is not working clean the jet

Find the gas valve and turn it to pilot. (Or light) Use a long reach lighter. Light the lighter and press the knob in. Light the pilot and continue to hold the knob in for about 15 seconds. When you release it, the pilot should stay lit. If it doesn't, you need a new thermocouple. That's the small tube that the flame touches when the pilot's lit. They're inexpensive and usually not too hard to replace.