______________________________________________________________________ Help! I bought a vacation house in Kirkwood, CA in January of 2000. Kirkwood is a ski resort south of Lake Tahoe, at an elevation of 7800 feet – it gets cold here! The house has a Carrier Weathermaker 9200 two zone furnace, converted to run on LP. Every year I come up here on a weekend winter to discover the furnace has stopped working, always with an LED error code of 31. The manual lists a large number of potential causes. I have new filters, so it’s not that. I’ve had several people come up here and try to fix the problem, making various adjustments to what some kind of pressure sensor, but they don’t seem to have a definitive understanding of what happened. Sometimes if I “reboot” the furnace several times by unplugging the main power and plugging it back it in the third or fourth startup sequence will work. Any ideas how I can fix this problem? Replies: jambras “Re(1):Code 31 on Carrier Weathermaker 9200″ , posted Sun 5 Mar 18:45 ______________________________________________________________________ It turns out that replacing my vent pressure switch fixed the problem here. Jim wanes98 “Re(2):Code 31 on Carrier Weathermaker 9200″ , posted Wed 29 Nov 21:27 ______________________________________________________________________ Hi; I am having he same problem. Would you please help me locate the “pressure switch” thanks wayne wayne SuperDave “Re(1):Code 31 on Carrier Weathermaker 9200″ , posted Sun 12 Dec 13:29 ______________________________________________________________________ What is the altitude at your vacation home? SuperDave jambras “Re(2):Code 31 on Carrier Weathermaker 9200″ , posted Sun 12 Dec 17:28 ______________________________________________________________________ The house is at 7800 feet above sea level. SuperDave “Re(3):Code 31 on Carrier Weathermaker 9200″ , posted Mon 13 Dec 23:40 ______________________________________________________________________ OK, let’s see if someone can fix this? #1 have the service company test the differential static pressure across the heat-exchanger. It’s normally around 2.25 to 2.50″ WC at 2000 ft and below. So at 7800 it’s much lower, it might require a switch change to a lower differential setting. #2 If you cannot get the help you need contact the local Carrier Distributor (HAVE THE MODEL, SERIAL AND INSTALLATION DATE) near your vacation home, they will be more comfortable with high altitude installations and will know if you need a switch change. #3 Make sure your PVC piping is within the tables limit in the installation instructions. #4 Ask the distributor if they have any service managers bulletins on your furnace. Good Luck SuperDave Xenos Webmaster “Re(1):Code 31 on Carrier Weathermaker 9200″ , posted Sun 12 Dec 12:24 ______________________________________________________________________ 9.9 out of 10 times its the vent pressure switch and the main cause is water logging up or the venting becoming restricted. Xenos. The best way to escape a problem is to solve it. jambras “Re(2):Code 31 on Carrier Weathermaker 9200″ , posted Sun 12 Dec 17:39 ______________________________________________________________________ Thanks for the quick reply! What should I look for regarding where water would be logging up? I checked the vent pipe and it’s still six feet or so above the snow level. Is there an easy way to check that the vent pipe airflow is ok? Also, looking at the owners manual there’s mention of a plug that needs to terminate the blue & white striped collector box drain tube. There is no plug at the end of the tube. Could that be part of the problem? SteveHVAC “Re(3):Code 31 on Carrier Weathermaker 9200″ , posted Thu 16 Dec 00:17 ______________________________________________________________________ Code 31 is a common problem noted in these and other forums. I think Xenos is correct that the problem is often waterlogging, although somtimes it can be a vent obstruction. I recently had a problem on a Carrer 58MVP that started with a Code 42 (induction motor not at correct RPM) that later became a Code 31 problem. Here’s the story: After observing the Code 42, pulled the inducer motor and housing containing the inducer motor wheel. There was a lot of water in the condensate drain, which should have told me something, but I didn’t know enough at the time. I flushed out the housing,reseated the inducer motor wheel just in case it was rubbing on the housing and reassembled everything. Furnaced worked perfectly for one week. Then got Code 31. I again disassembled the same components, checked all of the tubing (e.g., if the condensate tube drain is blocked, this can cause the problem, but it was OK). Also checked the intake and vent lines to see if there were any obstructions — this can also cause this code, but again no problem. I also ran the procedure of priming the condensate trap to be sure water was flowing. It was, but I now realize it should have been flowing more freely. Pressure switch checked OK, but these can occasionally be intermittent. Problem turned out to be mildew buildup in the condensate trap — water was backing up in the system due to a restricted flow. Now works fine. JeffFinnan “Re(4):Code 31 on Carrier Weathermaker 9200″ , posted Mon 20 Dec 04:46: ______________________________________________________________________ I ran into no heat yesterday as the temperature outside has already dropped into single digits and had called the heating service. However, when I was called back the heating was back on. I told the guy that I guess I did not need him. He was busy and was fine with that. Not long after, I kept losing heating. Not a furnace guy, I snoop around with turning off the power to the unit as well as turning off thermostat. After looking at the details pasted onto the back of the cover, I say the information on the LED codes. I quickly figure out it was 31. I then found this forum here. I checked out the vent line. I happened to notice that the black cap for intake was nestled among the wires and figured out where it belonged. I figured some wind gust must have hit right and blown it off. That still did not cure my problem. I used a shop vac to blown the line and suck the line all to no avail. I saw the discussion about water logging. I took the black flex line and pulled it off the condensate drain connection. (I found a bit of a manual online.) Water poured out. That took care of the problem and heating seemed to be working continuously. I got up a 4 AM. It was colder than it should be in the house even though I had the thermostat on hold to be warm. The LED was on solid. I drained from the flex line again. I turned off the thermostat and power again. The heat is cranking a way again. Later, I will see if I can blow the pvc line that connects to the condensate drain connection and the drain from the cooling section of the air conditioning point. Is that okay if I do that. Can I expect any problems? Is there anything else I should check since the LED was on solid? Subsequent to my original here, I had to drain some more water after about three hours of running, about a quart. I did not know whether this was warranted or not but I ran the furnace with the flex line unhooked to the condensate drain connection. I notice that it is pulling air into the flex line. Now I know why the flex line has a collapsed look to it. Is it normal for that to be under reduced pressure, to be sucked in? Not knowing the appropriateness of running unhooked, I reconnected the flex line. Thanks, Jeff [this message was edited by JeffFinnan on Mon 20 Dec 07:44] Xenos Webmaster “Re(2):Code 31 on Carrier Weathermaker 9200″ , posted Sun 12 Dec 12:26 ______________________________________________________________________ P.S. honeywell has a thermostat that will call out if and when the furnace breaks down. It can call up to 5 numbers and will contuinue to call until it’s able to deliver it’s message. Xenos. The best way to escape a problem is to solve it.