HV AC Question: Humidity levels?
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The Facts: I live in a chicago suburb, the temperature outside right now is 27 degrees F. I have a high efficiency furnace built on its side laying on my dirt crawl space floor supported by cinder blocks. There is a tube that fills with water on the side of the furnace.The tube is feeding into what appears to be the blower motor from a 2 diameter round pancake fixture. Once the tube fills with water, the furnace doesn’t work. At this point I have been instructed from a professional HV AC person to drain the water. I just purchased a dehumidifier and placed it within 4′ of the furnace in hopes of solving the problem. For the last two hours that it has been on it has accumulated approximately 1 cup of water. The humidity at this time after the dehumidifier has been on for 2 hours is at 54%.
1. What should the humidity level be at the furnace, in my dirt crawl space.
2. Assuming 65 pints per 24 hour is more than enough of a dehumidifier for the space according to the Menard’s sign; Will a dehumidifier correct the problem.
3. Is the source of that air traveling through the tube that fills with water coming from the return register or from the intake on the side of the furnace, that is currently not routed to an exterior air intake (I am told this should be).
Max J: I can not leave the drain open, the blower motor will not kick on until the tube is re-inserted over the fitting. Almost as if there was pressure.
June 29th, 2009 at 7:22 pm
in heating mode, you shouldn’t really be getting any condensation considering 100% relative humidity at 27% is about 22% relative humidity at 72 degrees. Ideal humidity in the home should be 30-45% according to most HVAC standards, but it really boils down to personal comfort. If you’re getting that much water, until you get a second opinion on what’s going on with you’re specific system, I would recommend just leaving the drain valve open. Regardless of the relative humidity outside, you shouldn’t be getting any condensation, and the air inside isn’t going to give you any either if you’re heating it.
July 1st, 2009 at 12:53 am
Your problem is not humidity levels. A high efficiency furnace is also known as a condensing furnace, meaning that the exaust travels through a secondary heat exchanger where moisture condenses out of the gas. This is where the furnace gains it’s added efficiency. From there the condensation travels through a tube to the condensate trap. That is where your moisture is coming from. It sounds to me like there is a blockage somewhere in the drain system, not allowing the water to drain properly, causing it to back up into the furnace, and then into the pressure switch tubing. which prevents the pressure switch from closing, (the round pancake looking thing). so as a safety the furnace shuts down. That is why your furnace stops working once the tube fills up. You need a heating contractor to correct this issue before it turns into a bigger issue.
July 1st, 2009 at 8:17 pm
From your description the tube is probably running between the pressure switch (round pancake thing) and the inducer (blower motor) that is responsible for exhausting combustion by-products to the great outdoors.
Your HVAC person is a crackpot if he suggests periodic draining as a fix for this problem.
The solution may be something as simple as getting the sag out of the line between the two components. You really need to call and discuss this with a new heating contractor. Your old one appears to be F.O.S. (full of…….).