but I can say for sure that the dewpoint hovers very close to 70 degrees all summer here (as you know, I'm sure).
Haven't really been tracking dewpoints and temperatures. I'm not quite sure about the CFM setting, But it'll be somewhere between 1000-1250 cfm, from the manual. The furnace spec says 16x25" should be enough - even for a washable filter IF it's a "high velocity" one, which I have no idea if mine is. I guess I could see what it is with the filter removed, and also try a disposable filter (right now it's a washable one).
It's a 20x25" filter grill, 2.5-ton system, and a very short piece of really large diameter flexduct between the filter grill and the furnace. I am bewildered why I'm seeing 0.57 iwc on the return. It still seems like I ought to move at least one of those takeoffs I showed in the OP photos, certainly the one where the flexduct is 15-20ft long do you see any reason NOT to do that ? But yeah, probably need to do more than that. I suppose I could simply delete one of the MBR ducts. There are 4 ducts in the MBR and only 5 in the living/kitchen/dining area, which is 50% more floor area, plus cathedral ceiling sloping up to 16ft high with a loft. I suppose I should get some HVAC pros in, but I know some of you here know a lot about HVAC, and the engineer in me can't resist trying to fix it myself. I have one of those washable filters (20x25" for a 2-1/2 ton system). But should I not do it, is it possible it might make things worse ? I believe I understand the "two foot rule", that takeoffs should be separated by at least 2ft (unless they're on opposite sides of the trunk ?) and separated by 2ft from where the supply attaches to the trunk.Īnother factor, I bought a cheap digital manometer, and measured about 0.25 inH2O between the furnace output and the evaporator coil, and aboiut 0.57 where the duct from the filter grill attaches to the return side of the furnace. So this might not solve the problem, but it sure seems like it would help. One of them would even become a much shorter run (it's probably close to 20ft long now). Seems to me it'd be simple to move those takeoffs to the larger part of the trunk. Note where a couple of runs of 6" flexduct takeoff right after it narrows. Then, in the righthand photo, you can see where the trunk doglegs to the side to clear a foundation pier, and gets much smaller. All the ducts for the MBR attach to it (to the right of the photo frame). The lefthand photo shows the main trunk, where the furnace and indoor heat-pump coil feed into it. So it's not a problem now, but still it needs to be addressed.Įxamining the ducts, I can see what appears to be a simple way of at least partially remediating the issue. And since the woodstove is in the living area, the bedroom is still cooler than the living area, which is what we prefer). The product is sold in 12-inch-wide rolls. It is also available from online retailers. MusselBound: U.S.-made MusselBound is Lowes current adhesive tile mat. Both 12- and 16-inch wide rolls are available, ideal for backsplash application. Except we don't run the HVAC in the winter, because we heat with wood. It is available from online retailers, as well as Home Depot stores. It'd be a bad thing in the winter, because the bedroom would be too hot. It the summer, that's, good, because we like sleeping in a chilly room. (In other words, the system directs way too much air to the MBR, in both winter and summer. In summer, the MBR gets 5-10 degrees cooler than the rest of the house that's fine, and the reverse in the winter is fine too, since I heat almost exclusively with wood - and the MBR is cooler, not warmer.
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