randyb

a quick update.. I've got the furnace turned down so it doesn't kick on. Drying some cloths right now and decided to check the 4" vent. It appears to work properly...when the dryer is running fresh air is being sucked in from outside. In a bit I'm going to kick up the furnace and check the cloths dryer vent to see if it's actuall getting closed by the furnace suction.

I had the problem with "moisture in basement ceiling from fresh air vents" and remedied this problem by replacing the vent tubing and sealing up a good size hole that wasn't caulked in the 6" plenum vent at the rim joist side. I've gone on to rip everything out of my basement because it didn't look good. This picture below is about 15 minutes after I pulled the insulation and removed the wood frame, ice dam in the corner after about 15 minutes. Click to Enlarge 29.3 KB Anyway, i have installed 2" blue xps on the walls and 1.5"on top of the blocks. I'm still currently working on putting it in all in the rim joists as well. I'm using great stuff to seal up around all of my utilities (which were not done) sealing up around the treated wood that have 1/4" gaps between the masonary brick, you could actually see outside. Yep getting it sealed tight! Direct vent furnace Click to Enlarge 40.86 KB So, now I notice that on my 4" fresh air vent for the gas hot water heater (that's about 7" off the floor in a 5 gallon bucket) is getting ice sickles outside on the vent itself. The 4" is right next to the 6" vent for the plenum. 4' vent on the left and the plenum vent on the right. Click to Enlarge 29.83 KB I tied some small plastic strips on both vents and kicked on the furnace. Both plastic strips are being sucked into the 6" vent, so the air in the 4" tube is being sucked out of the house and back into the 6 inch vent. I placed a piece of wood between the two vents and sure enough the 4" vent plastic just dropped to a neutral hanging postion. Is this normal? When the furnace kicks on should air come in the 4" vent as well, or would there be a neutral pressure? Just this weekend we also noticed on the gas cloths dryer, the cloths have a bit a smell to them. I'm guessing that when the furnace kicks on it back drafts that a bit. When the drier is off and the furnace is on, the dryer vent is shut good and tight. Any thoughts? Thanks, Randy We have two carbon monoxide detectors and both have 0 peak readings.

it can get a bit cold here in minnesota at times. Last week we had straight temps -25 deg and windchills of -30 deg.

i was able to get to my project on Saturday. Ladybugs in the general area of the fresh are vents....yep, sure enough the bottom side of the large 6" vent was not caulked good enough. I don't think they could get a caulk gun under there too seal it. I used the great stuff before I put the new insulated piping back on. Even though it's only been 12 hours since sealing it back up I don't see any frost next to the vents and no condesation anywheres so far, although it's a warm 27 deg outside. Thanks for the ideas and comments. Randy

thanks for all of the responses! much appreciated. I had the hvac company come out that did the original install, not much from them except that I need more insulation...hummm, that's why they replaced both of those vent tubes years ago. O'well there is clearly an air leak! But they said they would put in an HRV for about $2k. The problem is in the Northwest corner and right at the fresh air vents where they enter the home. The plastic covering does have several holes in them so that doesn't help either. I hold my lighter next to the tubes right where they enter the home and when I kick on the furnace the lighter flame starts to dance around. There has to be a leak there. I'm begining to think perhaps it's the fresh air vent frame (hope that's the term)on the outside, I would think that should be calked. I'll check this weekend when we temps get to the low 30's. Question? is there a calking that I can use in those low temps and work? I'll need to replace the insulated tubing as well. The tube that drops to the floor (water heater vent) is a 4" tube (R-4.2 F214) The second vent tube is what the Hvac people said was an 11" insulated tube that they put in on their second trip years ago. I can feel what feels like a 3' tube or pipe inside from where it meets the house and headed towards the plenum. Only one of the insulated vents are wraped in black plastic, the other is the 4" one that is sliver in color, but would appear to be a vapor retarder. both vents on the outside of the house could be exposed to some wind driven snow, they are about 1' 6" off the ground. I believe you are correct that the air is coming from the outside. My humidifier sat next to the fresh air vent that drops off 7" off the floor. I've shut it off now because the hvac tech says that my house is too moist. His meter says 42% today and mine said 38% (30deg outside temp).That's a bit on the high side...it's warmed up. I haven't been able to measure the combution air pipe yet, I'll do that this weekend when I have new tubing and large ty wraps to seal it back to the pipe. I would think that the tubing should be calked as well to the wood just inside the house. Here are the vents outside.. Click to Enlarge 42.13 KB a picture of both tubes about 2' into house Click to Enlarge 38.44 KB thanks for the help. Randy

Hello, I had my home built in 04 with an unfinished basement. Minnesota winters get cold, and every winter it seems I get a great amount of moisture (ok...water) dripping off of the 4" insulated fresh air vent tube. The 1st winter we noticed this and had the contractor take a look, he replaced about the 1st 7' of insulated tubing. The next winter it did it again...builder went bankrupted. anyway this past fall I decided to insulate the celing for noise and hoping it would take care of my problem with the moisture. Nope..i just removed the sheetrock to check on it and it's wet up there again. i put up 5/8" (Noise) r19 (noise & insulating value) and those darn fresh air vents are soaking wet inside it's insulation. course it leaks right out of it because they replaced 7' of it and only taped it. The two fresh air tubes run along the west wall to the north wall where they are vented. In that area of the ceiling, like the next rafter over to the east is the heat vent for that room in the basement, so there is definately heat with in the general area of the insulated fresh air vents. I did put r19 all around my heat vent just to help keep the ducting somewhat insulated from the cool air up there. The rest of the basement is not yet insulated in the ceiling, althought all the walls are insulated and sheetrocked. I pulled the sheetrock on the wall just under this area and the walls are dry, just the darn fresh air vent is cold and wet. anyway..how can I stop the moisture from building up? I'd like to finish this basement but I'm afraid of all of this moisture. I have a choice furnace, direct vent system to the west side of the house (about a 10' run), the two fresh air vents go out the north side of the house (about a 35' run). The two fresh air vents..one is dropped next to the furnaced 7" off the ground and the second one goes directly into the fresh air side of the furnace. I do run a humidifier in the basement next to the fresh air intake by the furnace, and have a humidistat upstairs and downstairs, I keep the humidity about 32 to 38 percent. Last week I shut it off for three days (temps outside where like -20 below) and it was so dry the sinuses hurt. a few pictures... in/out for furnace fresh air vent into furnace fresh air side fresh air vent 7" off the floor in/out with exhaust heading towards outside Click to Enlarge 40.86 KB Click to Enlarge 58.4 KB Click to Enlarge 46.96 KB Click to Enlarge 53.21 KB my last house we had the heat exchanger system and had no problems. do these insulated fresh air vents (even in a fully finished basement) always get moisture in them? but just don't leak normally? Anyone have some direction for me on this. Thanks for you time, Randy