need furnace help

[irishfan]

My old Bryant 125-394u furnace quit working over the weekend. The pilot light stays on but the furnace won't light. I bought a new thermocouple as that seems to be a common issue but the new one has a much longer probe on the pilot light end. Can anyone tell me if that is normal of if I can find a better replacement that fits correctly. The current probe on the flame end is only about an inch long and it is a clamp style holder not a push in. Thank you for any positive input.

 

[churchmouse]

If the pilot stay lit the T-coupler in not the issue.

If you use the stat and put the pan in the On position does the fan run. Simple test for 24 volts. If it runs you have control voltage. If not that is a place to start.
Do you have a VOM meter and the skills to use it. Simple question and not being wise guy. I can put you on some places to check for power.

There could be any number of issues with this unit. If you do not have the skills to run down the control circuit then calling someone is the best thing.

 

[irishfan]

yes i do have a meter and know how to use one just not a regular at furnace repair. The fan comes on so that is what led me to thinking its the thermocouple. I tried emery cloth on the old one as well but that did not help either. At this point I am just using YOUTUBE and basic DIY so any help is apprecaited

 

[churchmouse]

-Set the stat to heat. Turn it up past room temp.
-Set VOM for A/C voltage low scale as you are looking for 24V avg.
-The gas valve will have 2 wires. If it has more I need a pick. But I am working from memory here ()
-Check those 2 wires with the VOM and see if you have 23/27 volts there. (on a call for heat)
-If you do there is a solid chance the valve has failed.
-If you do not you have a safety that has opened. Look around and see if any have reset buttons on them. That old girl may not have these.
-If is a high temp safety the best I can tell you is find the wiring schematic and check them with an OHM meter for open.

Hard to diagnose over the interwebs but lets give it a try.

 

[Spike Jones 5 2002]

Where is your location?

 

[irishfan]

Im in New Castle. Church Mouse I will give those a try and get back with you. I appreciate the information

 

[maxwelhse]

You might try to pull a manual for your furnace and work down through the troubleshooting guide, particularly if your model is new enough to have error codes. I went to one of those "pay an expert what you think their advice is worth" sites and an HVAC tech send me PDFs of both the installation and operation manuals for my furnace and A/C plus held my hand for a couple of questions while I tried a couple things. Tossed the dude a well earned $10 (10 years ago...) for his trouble. I used those manuals about a dozen times over the years until I sold the house. I shoulda tipped that guy more money...

FWIW, what led me to get desperate and actually pay for help ended up being a failure of the wiring from the thermostat (due to an absolute moron installing it). In my case the fan worked too, just the wire to call for heat had died. If you obtain a manual for your unit, it should explain where to jump it to bypass the thermostat. Normally that stuff is all standard colors and terminal IDs, so you might be able to just wing it, but you never know...

Good luck!

 

[churchmouse]

You might try to pull a manual for your furnace and work down through the troubleshooting guide, particularly if your model is new enough to have error codes. I went to one of those "pay an expert what you think their advice is worth" sites and an HVAC tech send me PDFs of both the installation and operation manuals for my furnace and A/C plus held my hand for a couple of questions while I tried a couple things. Tossed the dude a well earned $10 (10 years ago...) for his trouble. I used those manuals about a dozen times over the years until I sold the house. I shoulda tipped that guy more money...

FWIW, what led me to get desperate and actually pay for help ended up being a failure of the wiring from the thermostat (due to an absolute moron installing it). In my case the fan worked too, just the wire to call for heat had died. If you obtain a manual for your unit, it should explain where to jump it to bypass the thermostat. Normally that stuff is all standard colors and terminal IDs, so you might be able to just wing it, but you never know...

Good luck!

His furnace is an old standing pilot model. I am wagering it is all analog. But yes, a good wiring diagram is essential.

 

[churchmouse]

You might try to pull a manual for your furnace and work down through the troubleshooting guide, particularly if your model is new enough to have error codes. I went to one of those "pay an expert what you think their advice is worth" sites and an HVAC tech send me PDFs of both the installation and operation manuals for my furnace and A/C plus held my hand for a couple of questions while I tried a couple things. Tossed the dude a well earned $10 (10 years ago...) for his trouble. I used those manuals about a dozen times over the years until I sold the house. I shoulda tipped that guy more money...

FWIW, what led me to get desperate and actually pay for help ended up being a failure of the wiring from the thermostat (due to an absolute moron installing it). In my case the fan worked too, just the wire to call for heat had died. If you obtain a manual for your unit, it should explain where to jump it to bypass the thermostat. Normally that stuff is all standard colors and terminal IDs, so you might be able to just wing it, but you never know...

Good luck!

We have not gotten to the stat part yet. Jumping R (red if properly wired) to W (white if done right) to see if you fire the burners. The fan function was just to see if he has 24V to run it.