Carrier heater

My Carrier heater began to have problems a few weeks ago. First it would work with the regular program cycle on the thermostat but would not kick on with the ovverride function. Now it will not come on at all. I have an identical thermostat that is working fine upstairs so I switched the thermostats and the problem still remains. When I checked out the unit itself, I can hear clicking etc. when I activate the cover interlock switch and occasionally I get a little flash of flame at the pilot but only for a fraction of a second and then nothing else. Fan runs OK on manual but doesn't turn on when activated by the thermostat. Any help would be appreciated.

 

how old is it? sounds like the pilot burner may acting up, if this is spark...if so clean the spark electrodes

 

get to the low voltage terminal strip in the air handler, does it have an R,W,Y,C....where the thermostat wires are connected?
This is a warm air gas fired furnace???

 

Yes its a warm air gas fired furnace. Terminal strip has the following:

C Y GC GH R W

What can I do next? Can I short any of these together to manually start the heater?

 

GH to W

 

Sorry....that should have been RH to W, I think you got that a little mixed up on the lettering... You should have an RH and an RC this is basically the low voltage hotfor Heat(RH) or Cool(RC)

 

the C terminal is the return side to the transformer, usually grounded side (if the transformer has a grounded side, some don't ground it)

 

No it's definitely GH and GC. Also there is a jumper J1 between the R and GH terminal. What's next?

 

Assuming that GH is the same as RH I jumpered GH to W and pushed the cover interlock switch. The pilot burner electrodes sparked 8-10 times, the pilot lit, then the spark stopped and the pilot flamed shrank slowly to nothing. Released and reactivated the cover interlock a few times and got it to repeat this action again then nothing. Now what?

 

we need to see how this unit knows when the pilot is lit. Some have a sensor rod in the pilot flame , it usually turns yellow when it's hot. The ignition wire is the fatter of the two. I believe the sensor wire goes to #4 on a standard module. Carrier will probly have a Fenwal control board. Look for a wire marked S, or better yet, just follow the sensor wire back to the module. Make sure the connection is secure. Use some 0000 steel wool to polish the sensor rod, and try it again. If you have a volt ohm meter let me know!

 

I don't see a sensor rod of any kind in the pilot area. This is a spark ignition type unit and the pilot doesn't stay lit all the time.(you probably know that). There is a large orange wire that comes from the ignitor/lockout control box and goes to the electrode that makes the spark. There are 3 small wires color yellow green and white that come out of the pilot spark module and go to a 3 pin molex type connector. Three larger wires color brown white and yellow go from there to the gas valve and then the yellow and brown continue on to the ignitor/lockout control module and the white goes down to the area where the fan is located. I have a meter and I have an electronics background so fire away and I will follow your instructions. Have repeated my test shorting the GH and W wires and get nothing now. I have a digital cam if a photo would help.

Thanks so much for your help.

 

The most common thing on Carriers that go is the three wire pilot switch. Dollars to donuts its gone!
24V goes from Yellow wire on switch to the green till it sences the heat and then flows from yellow to white wire....This will most likely go to the board OR the main gas valve...to release main gas. Give me a photo of the schematic....and the ignition board...

 

that is called the pilot burner, like i said earlier, replace it

 

I took out the pilot burner, cleaned everything real good, took out the ILO and checked and cleaned all the connections. cleaned and reseated every connection I could see. I plugged the heater back in and shorted the GH to W and the Pilot burner sparked 8-10 times, started a little blue flame then went out. No real change from before except maybe it sparked a few more times.

I took some photos to help with identification.

 

more photos

 

I guess I can only attach 1 file at a time.

 

again

 

last one

 

how can I get to see them????

 

try jumping R to W

 

Jumping R to W is the same result as GH to W (there is a jumper between R and GH on the circuit board

I attached the files to the last replies but it doesn't look like they came across. If you have email I could send them to you. Send me a message at burtr@netsmithinc.com and I will send them to you that way.

Thanks again

 

My carrier furnance in the garage stopped working a couple of weeks ago I asked someone at a furnace store locally and tried jumping the rh-w and I hear something in the control unit but I get no spark on the igniter. Since these are common to die and it looks old sould I try to clean it or just replace it? about how much are they and where can I order one form? can I get one at like home depot or a local hardware. I'd like to spend as little as possible

carrier
mod# 58gs12502
series 201
serial# k9a53165
think its 125,00 btu

anyone have any idea how old this is
and is It worth putting much into?

Thanks

 

replaced that pilot burner yet?

 

Do you have a hot surface ignitor, or a spark type ignitor?
If you have the spark type, you should hear the telltale tick-tick-tick... The unit will normally do this three times then quit. The PV terminal should have 24V to it first...Does it?