nixond Posted February 3, 2009 Report Share Posted February 3, 2009 I have a Rheem Classic Series Super Quiet 80 gas furnace. The unit is not quite three years old and every winter I have the same problem. When the winds get up and start to gust over 30 mph, this causes the heater to cut off and/or lock out until the winds die down. Once the winds are steady, and die down the heater turns on and returns to normal. The local technicians cannot identify any hardware malfunction. The ownerââ¬â¢s manual lists several safety features. One of which is the pressure switch that monitors pressure conditions within the furnace vent system during the heating cycle. Further, it states that there are several reasons for the pressure switch not to close. Item number four - "Severe downdrafts cancelling the draft from the inducer fan." The technician believes there could be a downdraft problem that may be causing the pressure switch to open. The technician replaced the pressure switch and installed a high wind flue cap. The condition is still the same. Do you have any thoughts? Quote Link to comment Share on other sites More sharing options...
energy star Posted February 3, 2009 Report Share Posted February 3, 2009 Could you post a pic of the flue vented out the roof? Quote Link to comment Share on other sites More sharing options...
nixond Posted February 3, 2009 Author Report Share Posted February 3, 2009 Inside or outside? Quote Link to comment Share on other sites More sharing options...
energy star Posted February 3, 2009 Report Share Posted February 3, 2009 outside. Quote Link to comment Share on other sites More sharing options...
nixond Posted February 3, 2009 Author Report Share Posted February 3, 2009 This side faces north. Click to View 23.07 KB Quote Link to comment Share on other sites More sharing options...
energy star Posted February 3, 2009 Report Share Posted February 3, 2009 Wow, That baby is really up there, and what is against the other flue? Shorten that thing a bit. It is 6" B-Vent (flue Diameter) Quote Link to comment Share on other sites More sharing options...
Brandon Whitmore Posted February 4, 2009 Report Share Posted February 4, 2009 Bill, You are telling him to shorten the B vent, correct? Judging by the slope of that roof, that is likely the required height. What are some other options? Quote Link to comment Share on other sites More sharing options...
hausdok Posted February 4, 2009 Report Share Posted February 4, 2009 Hi, Those look like they might be more than 3ft. above the roofline - aren't those puppies supposed to be supported by guy wires when they're more than 3ft. above the roof (maybe it's 4ft. - I can't recall off the top of my head. I'm thinking some kind of mechanical anti-backdraft damper is needed on that guy. It slams shut when the wind gusts up, but seconds later when the gust drops off, it swings open and lets the exhaust out. If they don't make such a turkey, perhaps a power vent up in the attic that's interlocked to the furnace. Furnace comes on, the power vent comes on and prevents backdrafting. Furnace shuts down, power vent goes off; I know they make those 'cuz I've seen them before. ONE TEAM - ONE FIGHT!!! Mike Quote Link to comment Share on other sites More sharing options...
energy star Posted February 4, 2009 Report Share Posted February 4, 2009 I wanted to ask the roof pitch, but I did not. He may not know. Quote Link to comment Share on other sites More sharing options...
Richard Moore Posted February 4, 2009 Report Share Posted February 4, 2009 HVAC isn't my strongest suit, but I'd have to wonder why this otherwise normal set-up would require anything non-normal like an extra power vent? Nixond already posted "The technician believes there could be a downdraft problem that may be causing the pressure switch to open. The technician replaced the pressure switch and installed a high wind flue cap.". I think it's quite logical to have suspected a overly sensitive pressure sensor. Evidently, that's been replaced and that does look like a Simpson high wind vent cap. Next, I would suspect something about the shape of this roof and/or the neighboring structure/roof causing an unusual high pressure vortex in the region of the termination. It might need a taller, not shorter flue. That would be very difficult to diagnose unless you happened to have the tech there at the right time. Nixond, it seems like your HVAC tech is actually a knowledgable guy. He tried the obvious. It didn't work, but I think you would get better advice on further options from him than what we can offer "off-the-cuff" from afar. Quote Link to comment Share on other sites More sharing options...
kurt Posted February 4, 2009 Report Share Posted February 4, 2009 I think that's good advice. Quote Link to comment Share on other sites More sharing options...
hausdok Posted February 4, 2009 Report Share Posted February 4, 2009 A steep roof like that will cause winds to spill and downdraft sharply as they cross the ridge; it's one of the reason that pilots are taught not to fly too close to the downwind sides of the crests of mountains. ONE TEAM - ONE FIGHT!!! Mike Quote Link to comment Share on other sites More sharing options...
energy star Posted February 4, 2009 Report Share Posted February 4, 2009 I bet thats five or six feet in the air. 12/10 pitch? Quote Link to comment Share on other sites More sharing options...
nixond Posted February 4, 2009 Author Report Share Posted February 4, 2009 First, I would like to thank everyone for their replies. Just FYI, the furnace was part of an original install for my new home. My home is nearing three years old now. I have had three contractors/technicians look at this unique problem, and they are all stumped as to the root cause. I will try to include some pictures of the furnace as time permits. Quote Link to comment Share on other sites More sharing options...
Scottpat Posted February 4, 2009 Report Share Posted February 4, 2009 I'm with Richard. Also you might want to contact Rheem/Rudd, this might be a problem that they have run across before. This their phone number in Fort Smith, AR. (479) 646-4311 Ask for their technical department or desk. Quote Link to comment Share on other sites More sharing options...
energy star Posted February 4, 2009 Report Share Posted February 4, 2009 Shorten the flue two feet and the problem will go away. Thats my guess from this limited info. Get back to us and tell us what the tech said. The only condition that changes (fluctuates) is the out side air , WIND. As posted above when the wind picks up and the location of the flue in relationship to the top of the roof create an effect that wind is throwing air down the flue. When the wind is less than the 30 mph gusts as you said, the terminal throw (sorta) is dissipated by other wind currents, it loses it's strength. So my guess is that the flue is cut in to close to the peak or the flue is too high.. Quote Link to comment Share on other sites More sharing options...
Richard Moore Posted February 4, 2009 Report Share Posted February 4, 2009 Thread drift... I'm being watched! After googling high wind vent caps yesterday, this ad is now appearing on my Yahoo news pages. Click to View 33.71 KB Coincidence? Maybe I'm being paranoid, but I think someone's got their hand in my cookies jar. Quote Link to comment Share on other sites More sharing options...
energy star Posted February 4, 2009 Report Share Posted February 4, 2009 telekinesis? Quote Link to comment Share on other sites More sharing options...
hausdok Posted February 4, 2009 Report Share Posted February 4, 2009 Hi Rich, Did you ever download that google tool bar? OT - OF!!! M. Quote Link to comment Share on other sites More sharing options...
Richard Moore Posted February 4, 2009 Report Share Posted February 4, 2009 For IE? Yeah, I got that. No big deal. Kind of clever targeted marketing actually. Quote Link to comment Share on other sites More sharing options...
hausdok Posted February 4, 2009 Report Share Posted February 4, 2009 Well, Maybe that's how they're tracking you. ONE TEAM - ONE FIGHT!!! Mike Quote Link to comment Share on other sites More sharing options...
energy star Posted February 5, 2009 Report Share Posted February 5, 2009 I'm starting a forum, wish I knew how to do that. Quote Link to comment Share on other sites More sharing options...
MechAcc Posted February 18, 2009 Report Share Posted February 18, 2009 The problem could be that high wind conditions may be actually causing a high draft condition rather than a down draft and closing the pressure switch before a call for heat is initiated. The ignition control box is doing what it's supposed to do. One option Trane gave us on one install was to install a double action barometric damper with spill switch. Contact Rheem/Ruud about this possibility. If however it is downdrafting and preventing the pressure switch from closing I would use the Field Controls Star Kap. It is much better at keeping a draft than the photo of the one installed. http://www.fieldcontrols.com/starkap.php Another option is to vent the furnace with a side wall venting system by Tjernlund or Field Controls or a chimney top venter. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.