I've been fighting with a few Carrier 59SC5A furnaces that lockout with Code 31. Carrier has released a Bulletin TIC2013-0007 (http://www.hvactechgroup.com/files/Carrier%20condensate.pdf) advising not to hookup AC drain lines onto the furnace drain line air vent, unless you leave an air gap.
Carrier also advised me to use a 3/16" drill bit to enlarge the high pressure switch tubing port on the ventor motor, to prevent water droplets from impeding the airflow into the HPS. These fixes seem to be working. Download the Bulletin #DSB 14-002 (http://www.hvactechgroup.com/files/dsb14-0002.doc)
There's also an unrelated Bulletin TIC2013-0014 (http://www.hvactechgroup.com/files/Carrier%20condensation%20rust.pdf) addressing the cause of excess condensation and rust inside the furnace. They will be revising the manuals to require a drain tee be installed on the intake vent if the intake hub is installed on the top of the furnace.
Look like very good info and I think this principles apply to all high efficiency furnaces.
It looks like ICP 35" furnaces have the exact same problem. See the attached Tech Bulletin I081 and DSB 14-0010 .
i have had this issue in the past and changed everything on the furnace. once i changed the ventor motor the furnace started to drain and function without any problems
had numerous issues with these furnaces and this problem, none of their solutions work too good, the only solution I've found to work is to tee of the 2 pressures switches together and connect the tube to the collector box port and cap of the vent motor port. The vent motor sits so much lower than the collector box when the furnace is in the off cycle all the condensate migrates to the bottom of it and there a ton of condensate it has to push out before the switches will make. Terrible design in my opinion. Ive had lots and lots of talks with their tech support and their solutions are just bandaids.
We had 2 furnaces that still kept having code 31 lockouts after following the technical bulletins. We seemed to solve the issue once we replaced the inducer motor.
Good to hear that solved the problem guess it could be a seal issue allowing to much air and not allowing furnace to drain
Hi,
I have the same model and issue. It keeps getting Error Code 31. I thought it was the drainage issue since I heard the water noise at the beginning of the furnace start up from the inducer. I have cleaned up the P-trap(I did not leave any water in the P-trap), but I still keep getting Error Code 31. Should I just replace the inducer and the Pressure Switch? Where do you get the parts from? How much do they cost?
Thanks,
Jonathan
They have fixed this issue on the newer vent motors. There will be an X stamped somewhere on the body (sorry, I can't remember specifically where) of the inducer assemblies that have a slightly enlarged pressure tap. They actually made a new die for them in the factory.
Hi Ted,
Thanks for the reply. My furnace is less than 5 years old. I would think they would provide the parts for free?
Also, leaving the upper access door open seems to be working at the moment. Maybe it somehow creates more vacuum by leaving the door hatch open.
Thanks,
Most likely a venting issue if you are not experiencing any issues with the door off.
Yeah my thoughts exactly.... If it works with the door off I would be looking real close at that venting/intake pipe.
Also, as for a free replacement part, I doubt it. They may have a 5 year warranty, but if it never was registered properly you would be out of luck.
I just opened up the induce motor outlet. There is a quite bit of condensation in the pipe. Is that normal? The vent pipe was not properly angled and causes the water to accumulate in the pipe.
I am going to check the inlet tonight (I thought the inducer outlet was the inlet...)
Thanks for the help
Just as I suspected, there is just condensation in the intake pipe. I am a bit confused what is really causing the 31 error code. Is it the condensation in the inducer motor? I do not see how I am able to prevent it from condensating. It has been pretty mild winter in the north. I think I should it give it a stress test when we are hit with a blizzard.
After vacuuming air inlet and outlet, I am still getting the error code 31. I am running out of options. I am thinking it is still the inducer motor.
Remove the high pressure switch tubing off the ventor motor port and shine a light inside. Do you see a water droplet covering the outlet port?
I would follow the bulletin above and enlarge the high pressure seitch port on the ventor kotor, or replace the ventor motor.
Also read the other bulletin and ensure your drain lines are installed correctly.
A technician came and thinks flame was not properly calibrated, it was at around 3.7 w.g. He eventually resolved the issue by cutting the air inlet which is the same as leaving the upper door open.
Thanks everyone!
That's not really a fix. A manifold pressure of 3.7" wc would not cause a problem. The technician turned your furnace into a non direct vent system. Did he make sure there is a sufficient air supply now that the furnace is using indoor air?
I agree with Ted, the problem is likely with the intake pipe.
The problem is most definitely with an inlet pipe. If it doesnt work with the door closed and it works with the door open, there arent any real other alternatives. That furnace has an open burner box, so by opening the door, you simply suck the air from inside of the building, instead of outside. Whatever were the problems with the condensation, they were not what was causing your furnace to not work.
You might have snow/ice/plastic bag/leaves/children's toys/your neighbour's pet rat/anything else really stuck inside your intake pipe. Or perhaps you've done some gardening and piled up some extra soil near the intake pipe and it's not able to suck so well. It needs to be at least 12 inches from the snow level that you would normally have.
If you have a vacuum that blows air instead of sucking, you could potentially slide the hose into the cut apart length of the intake pipe (Since it is now cut) and turn it on. Then go outside and see if you can feel air coming out from the intake termination from the wall. If you do, you can at least "mostly" be certain that your pipe is not completely and totally plugged. Do that after you've made certain that the intake termination really does have those 12 inches of clearance from the ground.
How long are your pipes anyway?