I have a Carrier Weather Maker 8000 for which heating has refused to start this winter :mad: . On checking the error codes comes out to be 21 which states gas blockage. One of the suggestion was to shut off the heater and let it reset which has not helped. (Left it Off for the whole night but when started the next morning, it still did not start! :( ). The blower starts for 90 sec then the exhaust (I believe - the fan on the upper side) kicks in and the ignitor (thing that glows red) comes on but since gas fails to come, it glows for few seconds and then turns off. Any suggestion would be appreciated.

I checked again today and from what I can gather, the error code is 12 and not 21. The error code 12 translates to "blower on after power up" or "R-W Closed". I have no idea what all this means and how R-W Closed can be reset to Open. Any help would be greatly appreciated.

Thanks

Check this post.

https://www.askmehelpdesk.com/heatin...-a-182116.html

I read the answer and they following made sense to me
"You might have a reset button at the top of the furnace near the flue pipe that you can reset by pushing in at the center of the little circular button. If not, then the pressure switch may be faulty, or more likely the vent (flue) is restricted or clogged in some way. Other more in depth tests probably need a tech to determine the cause. Unfortunately this particular furnace was noted for numerous safety features, which on occasion become stuck or malfunction. However, when they are needed, they may save your life, so we tolerate the inconvenience."

However I am not sure what "flue" pipe is and what circular button is being described/mentioned. Is it something on the gas controls?

Thanks,

No a reset button near the top of the furnace. It is a high limit safety control. The flue is the pipe that goes outside.

I found (I guess) the reset button. It is a button that is sticking to the top of furnace with two wires going in and in the middle is the switch sticking out. I pressed the button couple of times before stating the furnace but it did not do any thing different. Then I pressed it during the period when the furnace started to run. It did not help either. One thing I noticed was that before starting the code indicates 12 (one small and two long blinks), however after the ignition fails the code switched to 21 (two small and one long blinks). I guess this confirm the blockage of gas. I have turned the gas control on and off just to see if that might help but to no avail.
As far as flue is concerned, that does not seem to be the problem, I have not opened it as yet. However the blower motor seem to run fine and it does not make any sound if the passage is blocked/partially blocked.
Any suggestion how the gas blockage can be removed.

Thanks

Are you sure you have gas and it is turned on to the home and furnace. Stupid question but I have run into this problem before. LOL


Use a meter and see if the gas valve is getting voltage during a unit start up. This info will help isolate the problem.

Basically I have two units, one for upstairs and the other for downstairs. Both are being fed by the same line. (One gas line splits into two). One is working and the other one is not. Since one is working I am assuming the gas is coming to the unit that is not working.

As for the current coming to the gas value is concerned, I have not checked that.

There are two wires going into gas valve (gas regulator), one of these (dark green) is connected to the body of unit and the other end is going to circuit board. (Kind of makes a "V", bottom of "V" going to gas valve, one top end going to board and the other going to body). I guess I do not have to check availability of current in this wire as it seems to be a wire making the ground connection. The other light green wire is coming from the board, which I guess I need to check if any current is flowing through it. Right?

Thanks once again.

Carrier furnace will run blower motor for roughly one minute(when powered up during a call for heat) After the minute is up, the blower motor should turn off, and the combustion blower(upper motor) will come on, starting the actuall call for heat. A short time after the combustion blower(also called a draft inducer) comes on, your glow plug starts to glow, a short time after this happens, your gas valve should open, creating flame.

Do you have one pressure switch or two? Check for votlage at the gas valve after the glow plug has began to glow, as hvac stated, you should get a reading of roughly 24v before the glow plug turns back off. Let us know what you find,

First of all my apologies for the delayed response. I did not have had a volt meter and now I have bought one.
By the way the wires going in the gas valve are not dark green and light green but green and blue. Green is connected to the ground and the blue is other wire.
Here is what is happening. I am getting 24 volts going in gas value as soon as I start the heater - I checked this by disconnecting the blue wire and connecting one end of volt meter to the blue and other to the gas valve where the blue wire is suppose to be connected into gas valve. However when I connect blue wire back to the gas valve and then connect one end to volt meter and the other end to green wire, I do not get any reading.

I hope I am doing what you are asking me to do for checking the voltage. Does it give you any idea?

Thanks

Can you take a picture of your gas valve and the leads going to it. If you can, please post it here.

Here are some pictures.

http://images.kodakgallery.com/photo...2815_0_ALB.jpg

http://images.kodakgallery.com/photo...2815_0_ALB.jpg

http://images.kodakgallery.com/photo...2815_0_ALB.jpg

http://images.kodakgallery.com/photo...2815_0_ALB.jpg

Hope these help.

I see nothing.

I see little boxes with X in the middle.

Well, I see the real "pictures" that I added. May be since I added these, therefore I can see them. What is the normal way of adding pictures here? As I try to add pictures here, it asks for a URL for the location of picture. I have uploaded pics to my Kodak Gallery and given the link of that location. How else should I add images here?

Thanks

Okay, Now I do not see the pictures as well. :) So I am in the same boat as everyone else except, my boat is freezing (LOL). I will wait until morning to see if someone can guide me how I can add pictures here. So far I have not been able to find either in help or via searching the web site that would guide me to add pictures here.

If you don't get a glow from the hot surface ignitor it may be burnt out. If you have a open limit. The blower will stay on until the limit is closed. If you have a call for heat or cool from the thermostat on power up of the furnace blower will run for 90 sec. and then the call for demand will start to work

I am not sure what you mean by open limit. When I start the heater, it indicates error code 12, the blower gets on which does go off after about a minute or so then the combution blower kicks in, the ignitor lights on but the gas refuses to come on. The ignitor glows for 10 to 15 secs and then since the gas does not come on, it switches off as well as the combustion blower switches off and at this point I get the led code 21.

Still trying to find how I can add pictures here. :confused:

Do you have one pressure swtich or two? Pressure switches will have a small orange, white, grey, or black (roughly 1/4 inch diameter) rubber hose connected to them. Please answer this question, may be a start to solving your problem.

I am not sure if I have any pressure switch. I do not see any rubber pipes of any color.

I would be willing to bet that you have at least one pressure switch.

If you have two, one will most likely let the glow plug come on, and the other pressure switch will allow the gas valve to open.

Seems like there should be three wires at gas valve. Should be 24v between hot and neutral when time for gas valve to open. The green ground is just that, a ground. Are you sure there isn't a wire that has come unhooked at gas valve. Look for any dangling wires that aren't hooked to anything.

Could have a Hall Effect Sensor?

I took one of my office mate's help to post the pictures. Let us see if this link would work.

http://picasaweb.google.com/ulhaque.ahsan/Heater#

Let me know if it does not.

Thanks,

Try by putting this link in your browser if the above does not work.


Picasa Web Albums - Ahsan - Heater

Thanks,

That is a Honeywell gas valve I believe. There should be 24 volts going to that valve when the unit is calling for heat. Remove the wires and attach your test meter to read the voltage.

Yes, I do get the 24 v in blue wire when I disconnect it from the terminal and connect one end of volt meter to the wire and the other to the terminal. But as soon as I connect it back to the terminal it disappears. May be it is suppose to disappear or it could be the cause of problem.

"I am getting 24 volts going in gas value as soon as I start the heater - I checked this by disconnecting the blue wire and connecting one end of volt meter to the blue wire and the other to the gas valve where the blue wire is suppose to be connected into gas valve. However when I connect blue wire back to the gas valve and then connect one end to volt meter and the other end to green wire, I do not get any reading."

If you are getting 24 volts across the gas valve wires and the valve is not opening then I would have to say the valve is defective.

Quote:

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Originally Posted by MarkwithaK

Could have a Hall Effect Sensor?

---

YEP carrier and Bryant use them

Need to test across both terminal while supply wires are still connected. If you get 24v now, then your valve is bad. I believe you are testing the connections incorrectly.

Pulling the blue wire and testing between that and the spade that it connects to may give you a false 24v reading. When you put it back on, the 24v disappears. Need to test between the two wires( either while they are both connected to valve, or when they are both disconnected from the valve.)

Carreir uses the hall effect sensor on the packaged units but not with the split systems. Flame failure= no gas or no gas ignition on the flame sensor. In your case I would say you have a bad valve or very dirty burners and or burner orifice.

But do you know the reason Carrier/Bryant does not use the hall sensor on there other equipment. It has nothing to do with cost BTW.

Is this a quiz, cause if it is, I'm feeling a little weezy, think ill stay home today.


Is it just me or does it sound like novice is testing the valve incorrectly. Can someone here post some type of picture showing where he should have his tester leads.

I am sure I was testing it incorrectly as I do not know what I am doing :confused: However I plan to go and test using the two wires on the heater with two wires on the volt meter. I am sure I tested that but since I was not getting any reading I thought I was doing something wrong and then tested with just one wire. :( I guess I was wrong the second time.
I gather that if I do not get any reading when testing by connecting two volt meter wires to two wires on the heater, then the gas valve has gone bad. Am I on the right track here?

No, if you put two meter wires to two gas valve wires and don't read 24v, then the problem is not the gas valve. If you get 24v reading, then the gas valve is bad.

I tested and retested multiple times and I am not getting any reading when I attach two meter wires to two gas valve wires. I had set the meter to DCV 50 and then DCV 10 but still no reading.
One thing that is puzzling me is that when I do same test on the heater (I have two similar heater as mentioned earlier) that is working I am not getting any reading either. Am I testing correctly? If I'm should I not be getting some reading for that heater that is working?

Try using AC and not DC!!

I used AC this time and it confirmed that I am NOT getting any voltage on connections at the gas valve. I did check the other heater and I do get the voltage on the other.
What does this mean and what should be the next step?

Thanks

Your pressure switch could be stuck closed. If this is the case then on a call for heat the unit will sense this and will not lite. It is a safety feature built in. Try this. Turn the unit off and pull one wire from the pressure switch. Turn the power on and after the inducer starts up then carefully attach the wire you pulled. See if your unit fires. If so then you have a failed pressure switch.

If there is no voltage at the gas valve (I guess this is the pressure switch) would pulling wire and putting it back make any difference?

Yes. If the units senes that the pressure switch is closed at the initial call for heat then it will not open the gas valve. Again, it is a safety feature.

No. Nothing happened. I pulled the wire and then started the heater, When the inducer started, I put the wire back in its place but the gas did not come and hence no fire.