I have a Rheem Criterion furnace, about 10-11 yrs old. It turns on, the blower starts, no ignition. It cycles a few times but no ignition. I replaced the ignition, but nothing. There are no error messages on the board. Anything I can check before calling a technician?

Does your system have a hot surface igniter, or a spark igniter. How many pressure switches are in the unit? Check to make sure that the pressure switch tube port on the draft inducer is not plugged.

It is a hot surface igniter - it glows. Sorry, you lost me with the rest. I'm not sure where to look.

Okay, first, is the igniter glowing at all? The reason I ask, is because I need to know exactly what you mean by "no ignition". Is igniter working, but the flames won't ignite, or does the igniter simply not glow at all.

The tube on the pressure switch looks good. I only see 1 pressure switch.

The igniter doesn't glow at all. I replaced it today. I was careful not to touch it as well.

Sorry man, wish I could help, but duty calls, got to go on a furnace call, so I hope to be back tonight, or ill check in with you tomorrow.

Thanks for the help.

Okay, you said the blower starts. By blower, do you mean the big blower that circulates air in the home, or the small blower that exhaust burnt gases.

The small blower.

Turn furnace off, then, disconnect the tube that hooks between the pressure switch and the draft inducer(small blower) from the draft inducer(leave it hooked to pressure switch. Then turn the furnace back on. As soon as the small blower starts to run, lightly suck on the tube going to the pressure switch, keep sucking for about thirty seconds, or even longer. See if the igniter glows now, and if flame lites. Let me know. If not we will take the next step.

Good call. I did as you described, and the igniter started to glow. The furnace seemed to run normal after that - that is to say, it ignited the gas and the big blower turned on.

Good, now, the port on the draft inducer where you unhooked the hose, check to make sure it is not plugged up in any way. You can use a paper clip and stick it in there to clean it out. Then hook the hose back up and let me know if the furnace works properly. Ill be here for a little while so let me know asap.

The port has a little gray piece over it - because of that piece I couldn't stick the paper clip into it. I checked the hose to make sure there were no clogs.
When I turned the furnace back on and set the thermostat to call for heat, it appears to be working normal.
Two questions - what was the problem? And If it stops working in the next few days, what would you suggest I check or replace?

That's a hard call. Without being there to test things for myself, I don't like to suggest replacing parts, however in your case, I would start by replacing the pressure switch, they are fairly cheap and easy to replace. Glad to hear the furnace is working. Come on back if any further issues arrise. Take care. Lee.

PS. Make sure you are sticking the paper clip into the draft inducer(small blower) not the pressure switch.

I was definitely trying to stick it into the wrong part. Good tip. Good thing they idiot proofed it for us idiots.

Thanks again.

Ha ha. Yep, your lucky your pressure switch has the restricting device, or you may have ruined the switch. But as it is, no harm done.. Like I said, I'm just glad your back in heat, and let us know if you have any more questions.