Mike Lamb Posted February 18, 2014 Report Share Posted February 18, 2014 I looked at a Cat 4 furnace on a 3 story bldg. for a 2nd story condo. 10 yr old furnace and rehab. The exhaust was going out horizontally through an adjacent wall and the combustion supply was coming through the roof (I think). It was direct vent (2 pipe) so I cannot imagine why this was done. The exhaust and supply are supposed to be near each other. Nothing bad seems to be happening. Would you make a big deal out of this or just say this isn't the way it's supposed to be? Quote Link to comment Share on other sites More sharing options...
kurt Posted February 18, 2014 Report Share Posted February 18, 2014 Just a WAG.... The installer dweebed out and mixed up the intake and exhaust. I've been seeing installs where they've finally gotten smart enough to take the exhaust out the roof, but to save a penny they put the intake out the side. When the furnace went in, the guy never checked the pipes to see which was which. Quote Link to comment Share on other sites More sharing options...
randynavarro Posted February 18, 2014 Report Share Posted February 18, 2014 The intake and exhaust don't have to be near each other, just in the same atmospheric zone. Outside would be the same zone. No idea why the two pipes in two directions, though. Seems much more expensive. Sounds like the installer isn't up to speed on those furnaces. . . ? Quote Link to comment Share on other sites More sharing options...
Mike Lamb Posted February 18, 2014 Author Report Share Posted February 18, 2014 The intake and exhaust don't have to be near each other, just in the same atmospheric zone. Outside would be the same zone. No idea why the two pipes in two directions, though. Seems much more expensive. Sounds like the installer isn't up to speed on those furnaces. . . ? The Tappan instructions say not closer than 18" no further than 36" for vent termination. I think. I'll have to double check. Why atmospheric zone? Why wouldn't they just say "outside" or "within the mass of air that surrounds the earth"? Quote Link to comment Share on other sites More sharing options...
Mike Lamb Posted February 18, 2014 Author Report Share Posted February 18, 2014 I'll guess it has to do with balancing the venting process. I don't know whether to make a big deal out of this since I have not seen this before. The colder the climate the farther the spacing should be but within limits. The furnace in question is a Tappan FG6RC. There are many things wrong with this installation. This was just one. Click to Enlarge 40.81 KB Click to Enlarge 52.48 KB Click to Enlarge 42.18 KB Click to Enlarge 76.69 KB Quote Link to comment Share on other sites More sharing options...
Mike Lamb Posted February 18, 2014 Author Report Share Posted February 18, 2014 I got this reply from an HVAC forum and it makes sense. "The real world issues with terminating a high eff furnace flues in different pressure zones is that they will be subject to different airflow patterns. Wind on one sie and not the other will cause pressure switch waffling, nuisance board lock outs, and depending on how well they are run, water accumulation in the flue(s) which can cause the furnace to shut down and/or improperly burn. Another common issue with running them to different locations is that they will rarely be of equivalent lengths-presenting many of the previously mentioned problems" Quote Link to comment Share on other sites More sharing options...
SNations Posted February 19, 2014 Report Share Posted February 19, 2014 I got this reply from an HVAC forum and it makes sense. and depending on how well they are run, water accumulation in the flue(s) which can cause the furnace to shut down and/or improperly burn. I don't understand this part. It sounds more like an indictment of a poorly installed flue than a problem of running the flue and intake to different areas. Am I missing something? Quote Link to comment Share on other sites More sharing options...
kurt Posted February 19, 2014 Report Share Posted February 19, 2014 Sounds like the installer isn't up to speed on those furnaces. . . ? Chicago is the land of confused HVAC installs. We look at a lot of joints that were originally steam or hydronic, that were converted to condos or apartments a while back when no one cared; tech's stuffed equipment in any old place it would fit, even kitchen pantries with the return located in the kitchen. Ducts hidden in cheesey soffits, lousy air flow, vents into ventilation shafts, all sorts of crap. I'm betting this is one of those kind of places. Quote Link to comment Share on other sites More sharing options...
hoosier inspector Posted February 22, 2014 Report Share Posted February 22, 2014 Today would have been perfect to check if the wind was affecting it's operation. This was one of the rare occasions I refused to get on a roof or a ladder. Quote Link to comment Share on other sites More sharing options...
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