Central Air Damper Question...

[Jim B.]

After a short cold spell, I was finally able to turn on the central air conditioning tonight, I hope for good. But there is one question I have concerning it, maybe someone on these boards can help me with: Do you open or close the damper on the furnace as you do this?

I know when we got the A/C about ten years ago, they said putting it in the wrong position could lead to CO poisoning(!). Don't worry about that though. I still have a very good carbon monoxide detector. And if it goes off, I will immediately take the appropriate steps of course (judging from what I've seen in people's previous posts, I would never post something about my life being in danger obviously).

Thank you to everyone who helps

[Snnipe 70E]

Why would you change the dampers?
I just move the switch on the stat from heat to cooling.

[Jim B.]

Originally Posted by Snnipe 70E

Why would you change the dampers?
I just move the switch on the stat from heat to cooling.

Doesn't make any sense to me either. But as I said, when they installed it c. 10 yrs. ago, they said it was important for some (unknown) reason. BTW, for what it's worth, I turned off the AC, and I think I will leave it that way until tomorrow. It is supposed to be 76 tomorrow. So with my well-insulated house, that will be about 80 or so. I will turn on the AC then, and just deal with the heat as it comes.

[gotpasswords]

Originally Posted by Jim B.

After a short cold spell, I was finally able to turn on the central air conditioning tonight, I hope for good. But there is one question I have concerning it, maybe someone on these boards can help me with: Do you open or close the damper on the furnace as you do this?

I know when we got the A/C about ten years ago, they said putting it in the wrong position could lead to CO poisoning(!).

Are you talking about a flue damper on a coal-fired furnace or an airflow damper in the ductwork?

Usually with AC, you just want everything in the ducts wide open.

[raindog]

There isn't enough information in the OP to do anything but hazard a guess, but if you have a humidifier and if you have a small pipe (6") that has the damper in question and if someone has written in marker "summer" and "winter" positions on that 6" pipe that has the damper in it (which is associated with the humidifier) than, yes, close it in summer.

[ZenBeam]

The only way the OP makes sense to me is if they told you you could close the exhaust damper during summer, but to make sure to open it again when you switch back to heating in the Fall, so you don't get CO poisoning.

[thelabdude]

If you have a furnace that draws its combustion air from house as most do, and a damper on the flue, which may violate code, closing it in the summer may help keep warm, moist outside air out of the house.

I have a duct for outside combustion air with a damper. It is wired so that the heat won't come on unless the damper is open.

I think modern furnaces are wired so they shut down if the flue is obstructed. No safety device is 100% reliable.

[veridynamics]

The info I was given by a very honest and excellent father/son business is that the damper controls the feed to the humidifier so you want it open in the winter and closed in the summer.

This would also be the case if yours will not run if closed in winter for possible carbon monoxide being introduced from the gas furnace.
My system will run with it in any position but that is due to a separate air feed installed with new ac unit.

[ZenBeam]

I have such a damper on my furnace. There's a duct from the hot side of the furnace that takes air to the humidifier and then into the return air side of the furnace. That duct should be open in the winter and closed in the summer.

Having it in the wrong position won't give you CO poisoning, though, so I don't think that's what the OP was talking about.