Getting a Code 31 Error on Furnace model No. GB3AAV

[ccmulder]

Okay--I checed the blinking LCD and get a Code 31 Error, which says to check for a number of things but I think its this:

Defective Pressure swith or connections. The reason I say that is because right after that, it says, "If it opens after trial for ignition period, blower will come on for 90 second recycle delay."

Now that's what happens with mine. If I reset the door switch (i.e., just push in the switch that would be pushed in if you put the service access door back on), the heater comes on for 90 seconds and then shuts off. This problem was intermittent for a couple days--the heater would come on later at night, but now doesn't come on at all.

Is there any way to check for that/fix? If I need it a repair, what should it cost?

Attached is a picture--which is the Pressure Switch?

[ccmulder]

Here is a closer shot

[RegUS_PatOff]

I'm no expert, but it looks like that round blue diaphram thing in the second picture.

[ccmulder]

[user=3641]RegUS_PatOff[/user] wrote:

I'm no expert, but it looks like that round blue thing in the second picture.

That's what I thought--but its confusing--you can see on the attached diagram from the service manual (mine is the one on the right, but horizontal):

 

 

[RegUS_PatOff]

http://www.amresupply.com/product/HK06WC090

 

http://www.hvacpartsoutlet.com/pressureswitchcarrierhk06wc090.aspx

"NOTE; the new pressure switch may look and mount differently then the old switch it replaces. The connection terminals may also have to be changed, --in some cases you may even need to make a new mounting bracket from a small piece of sheet metal *not included, or change the wire connectors."

 

Check the Vent to see if there's any restrictions, i.e. critters.....

[ccmulder]

Where would the vent be?

[ccmulder]

[user=3641]RegUS_PatOff[/user] wrote:

http://www.amresupply.com/product/HK06WC090

 

http://www.hvacpartsoutlet.com/pressureswitchcarrierhk06wc090.aspx

"NOTE; the new pressure switch may look and mount differently then the old switch it replaces. The connection terminals may also have to be changed, --in some cases you may even need to make a new mounting bracket from a small piece of sheet metal *not included, or change the wire connectors."

 

Check the Vent to see if there's any restrictions, i.e. critters.....

Thanks for the link although I don't know if its the pressure switch.  Any way to check that?

 

[RegUS_PatOff]

[user=43530]ccmulder[/user] wrote:

Where would the vent be?

the metal vent pipe that goes thru the wall, or up the chimney...

[ccmulder]

[user=3641]RegUS_PatOff[/user] wrote:

[user=43530]ccmulder[/user] wrote:

Where would the vent be?

the metal vent pipe that goes thru the wall, or up the chimney...

Ok--I'll check tomorrow in daylight.  However, I jumpered the Pressure Switch and then I got a 23 code error (Pressure switch did not open) which I'm guessing unless the unit senses a pressure switch opening, it faults.  But I guess that still doesn't tell me if the pressure switch is working properly or not if something else is wrong.  I know the switch comes opens after trial for ignition because the blower runs for 90 seconds and shuts off. 

[ROBBYRIG]

Jumpering a pressure switch is different than jumpering other switches.  At initial start-up, the board needs to read the pressure switch as open.  After the inducer motor kicks on for a minute or so, then the pressure switch closes and the board will then allow the ignitor to glow. 

[ccmulder]

[user=34365]ROBBYRIG[/user] wrote:

Jumpering a pressure switch is different than jumpering other switches.  At initial start-up, the board needs to read the pressure switch as open.  After the inducer motor kicks on for a minute or so, then the pressure switch closes and the board will then allow the ignitor to glow. 

Is there anyway to test the switch? 

Also, how do I check the vent?  I don't know how to take apart the aluminum piping that goes from the unit to the roof--tried last night, but it doesn't just pull apart

 

[applianceman18007260692]

You probably need to blow out that rubber tube. The way to check the pressure switch is to suck on it. You should hear an audible click. Check for continuity. The way it works is the draft indcer motor causes suction and the suction kicks the pressure switch on which activates the ignition sequence. The ignitor comes on and the gas fires up, the flame sensor says everything is fired up and the heater warms up then the blower kicks on. NOTE: if the flame sensor does not confirm ignition because it is contaminated or the burner ground wire is loose then you will have the symtoms you have described. The main fan will do the 90 second thing just in case ignition did occur but the brain didn't get the word. You could try cleaning the sensor with soft emeory cloth or just replace it. Make sure all ground wires have good connections.

[ccmulder]

I did take the pressure switch off and sucked on it and heard the clicking sound so I assume that means it works.

[applianceman18007260692]

I have never seen a bad one yet. I worked at an HVAC parts store since 1995. Most of the time it is a blocled hose. bad draft blower or faulty flame sensor.

[applianceman18007260692]

I sure wish I knew why I can't type worth a damn today.

[ccmulder]

[user=4554]applianceman18007260692[/user] wrote:

I have never seen a bad one yet. I worked at an HVAC parts store since 1995. Most of the time it is a blocled hose. bad draft blower or faulty flame sensor.

Okay--I had a guy come out and troubleshoot it--he says its a bad master controller board (or inducer board).  Interestingly, he showed me that if I pressed up on the controller board with my fingers, it would make the system work.  So apparently I can stand their with my hand on the controller board or clamp it somehow or order a new one.  Any ideas on what may be wrong with the board or should I just order a new one?

[RegUS_PatOff]

[user=43530]ccmulder[/user] wrote:

...  if I pressed up on the controller board with my fingers, it would make the system work....   ... Any ideas on what may be wrong with the board or should I just order a new one?

bad solder joint, maybe on a Connector or Relay Terminal ...

Take a close look ...

[ccmulder]

[user=3641]RegUS_PatOff[/user] wrote:

[user=43530]ccmulder[/user] wrote:

...  if I pressed up on the controller board with my fingers, it would make the system work....   ... Any ideas on what may be wrong with the board or should I just order a new one?

bad solder joint, maybe on a Connector or Relay Terminal ...

Take a close look ...

 

Yeah--that's obviously it--a bad connection--but with a 13 year old heater, I thought its probably a better idea to just replace the board with a new one.  I didn't see any Model Number on the board though--how would I find a replacement?

[RegUS_PatOff]

http://shortyshvac.com/index.php?main_page=product_info&products_id=39 

325878-751 This board replaces HK42FZ004

CARRIER BOARDS 325878* on eBay

 

[ccmulder]

[user=3641]RegUS_PatOff[/user] wrote:

http://shortyshvac.com/index.php?main_page=product_info&products_id=39 

325878-751 This board replaces HK42FZ004

CARRIER BOARDS 325878* on eBay

 

I saw those when I searched but I was unsure which model it replaces They list HK42FZ0xx where "xx" are 08 07 or 11 or 13 or 16.  Does it matter which one I get or are the all the same?

[RegUS_PatOff]

I'm not a HVAC expert...

are there any such numbers on your board ?

[ccmulder]

[user=3641]RegUS_PatOff[/user] wrote:

I'm not a HVAC expert...

are there any such numbers on your board ?

I would have to take it out to see the model number--I can't see it from the outside.

[applianceman18007260692]

make sure all the board connections are tight and free of corrosion.

[ccmulder]

Well, the problem is a soldered conneciton--I Googled and found there to be a problem with these boards in that regard.  Right now its wording fine with a wedged piece of wood (covered in Tin Foil) pressing against the Board Plug, which is keeping the contact.  I'll take it out and take a look at it once this current cold wave (relative since I am here in Southern California) snaps.

[RegUS_PatOff]

Milwaukee, Wisconsin  +6 F 

but we have power, not like the Northeast  :brrr: