Intertherm furnace M1BG wont fire

by igniter I assume you mean the thermocoupler. are you turning the control button to run after you light the pilot light? Normally when those furnaces quit it is the thermocoupler that has quit. Get a new one and leave it in the furnace compartment as a spare.

your machine is missing the oxygen check your ventilation,
1. try to turn it for 1 minute with leaving the door open.

Try Googling the problem. Who have you paid so far, someone from the gas company, or a private technician? Was the technician from an Intertherm dealer? I would think a dealer would have qualified techs.

Furnace burner and heat element are not the same. I think the fan time delay, a sensor that turns the fan on when this sensor senses heat, is shot and needs replacing, for a furnace type heat ( gas heat)

If the thermostat is set on Fan and not Auto the fan will continue to run. If the fan control is bad or is set at too low of a setting, it will blow cold air after the furnace has shut off. From what I guess of your explanation, your furnace is not producing any heat and the room air blower runs blowing cold air. You may have two issues happening. Make sure your thermostat is calling for heat by setting it to a high setting. Inspect the thermostat to see if it is set at Auto. Go to the heating system and inspect it to see if it is heating. If you can't view any flames carefully touch the exhaust pipe and see if it is hot. If not, you have a no-heat condition. A 23 year old furnace may need some TLC so call a technician you trust. He/she may need to replace the ignitor or thermocouple to get it going. They will also check out why your fan is running when it should not.

Sounds like a problem with the circuit board.

Downstream of your fan discharge there is a little plastic assy. most likely that will have a pickup tube and a piece of vinyl or latex tubing attached. First check to make sure that the pick up tube and/or tubing does not have a restriction. If it is clean use an ohm meter to read resistance across the switch to verify it is operating.

if i understand your problem description correctly when power is on but the furnace is not running you can smell burning dust and feel heat? first thing i can think of is possible a heater relay has gone bad keeping the heater on all the time but no fan...

the blower on my furnace keeps going on and off when i turn the furnace on .ichanged the snapdiscs no change changed thermocoupler and therostat still no change whats my problem