Furnace not kicking on all the way

We had a mild flood in our basement over the weekend, maybe about 2-3 inches of water. I don't think any part of the furnace was submerged in water...maybe just the bottom - no electrical parts. Now the furnace is simply working half way. It makes all of the noises as though it is going to kick on, yet the heat just barely blows out of the vent. It is a gas furnace...any thoughts on what it might be, and is this a do it yourself job?

 

You provide about zero information on what the possible problem might be. You suggest that the furnace provides a small amount of heat, which could be caused by a plugged furnace filter --- I'd check that.

The usual method of diagnosing furnace problem comes with an understanding of the "sequence of ignition." A furnace doesn't just turn on --- it does a number of things, one after the other which results in heat at the end of the sequence.

Identifying where the furnace stops in that sequence provides the first clue as to where a furnace defect might occur.

Spending time watching and understanding that sequence when the furnace is operating properly is a good place to start if you want to be a do it yourselfer on furnace repairs.

You can try being a careful observer of the furnace as it is if you like, and report what you see and hear happening.

 

Okay, let me get into a little more detail...I turn the thermostat to 70, and usually, you can hear the "ignition" right away, but in this instance it takes several minutes. It makes a noise as though the motor is running, and the flames ignite, and then they turn off. This process continues over and over. If I feel the vents, there is a little heat coming out, but it is not blowing out as usual. Sorry if I'm not using the proper terms for everything, I'm not very experienced with furnaces!

 

You have to go down to the furnace, take the cover off and observe what is happening carefully, and probably at some length until you can see what is happening.

If you don't want to do that, forget it. You have no future as a furnace repairman.

 

Yeah, I will have to get someone to help me take the cover off and take a much closer look. You're right, I don't have a future as a furnace repairman...I guess that is why I am on here asking. Thanks for the tips.

 

Sorry, without better information I can't offer you much in the way of help.


My best advice for you is to look for an honest and competent repairman to help you. Referrals from friends, neighbors or relatives to a service agency that gave them good service would be a good place to start.

Unfortunately, too many repair services prefer to sell people new equipment rather than repair what people have.

 

When you are looking, with the big panel off the furnace - see when the flame shuts off in relation to when it first comes on. If it like about 4 seconds, you can almost bet on a flame sensor rod that needs some polishing up. This is a DIY job and can save you money on service call. Flame sensor has one wire leading in toward combustion chamber, and at end of wire the flame sensor rod is usually screwed to furnace with one screw.

Let us know also if you first have a pilot light that lights. And if so, if the pilot actually goes out, not letting any flame other than the pilot to light.

And similarly let us know if instead you have a hot surface ignitor(abbreviated 'HSI') that causes a bright glow to occur inside the front of the combustion chamber, just before the flame appears.