We bought a house with an insta-flame direct wall vent model fsdv 30 In the back there is a blue knob (assume it's the gas on/off) cannot seem to locate the pilot on/off knob nor the ignitor switch. It's pretty dirty with dead bves in it also, any info to clean operate etc. would be helpful

SOURCE: Glo-Warm Wall Gas Wall-heater parts...

try this site. I don't know what numbers will work but they have parts for dyna glo.
http://www.masterparts.net/glowarmnatural.html

SOURCE: natural gas patio heater

MAY I KNOW THE EXACT MODEL # OF YOUR UNIT.

SOURCE: Goodman GMP075-3 ignition problem

OK, if the furnace is not lighting for even a few seconds, you have either a bad gas valve, bad wire, bad control module or no gas. The pressure switch is not the issue. Check all wires to the gas valve and look for 24 volts across them when the ignitor glows and you hear the click. Then test for 24 volts to ground. It could be a bad ground wire.

SOURCE: I have a Goodman furnace

limit switch is on the heat exchanger black plastic about 1and1/2 in. by 2 in. with 2 wires going to it , it has 2 screws holding it in take it out and check it with an ohm meter and you should not have a reading if it is good

SOURCE: big old Hydro Therm boiler rolls out flame

need to clean burners causing delayed ignition.