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Black- high speed
Red- low speed
Blue- med. high
Yellow- med. low
Usually black on "cool" terminal on board, red on "heat" terminal on board, and remaining 2 on the "park" terminals on board. White goes to the neutral terminals. Hope this helps!
Solid red is normal, no call for heat. Try jumping (in the FAU) between the R and W thermostat terminals on the circuit board. Be sure when you do that the interlock safety switch is on delivering power to the heater, the red light is on. Also be careful not to touch the R side to any ground, it may blow a fuse within the circuit board. If that works, try jumping from the thermostat itself (remove the thermostat and jump the red and white wires) if that works, your thermostat has failed... replace. If jumping the terminals in the FAU fails to run the inducer fan I suggest you call a technician, as something in the circuitry has failed and will probably need to be replaced. If jumping from the thermostat wires fails, then the wire is broken somewhere between the thermostat and the FAU (either by literal break, or a signal interruption... like a security system or zoning system). Good luck.
disconnect the thernostat wires from the control board. Put a jumper wire between R & G put door back on and turn on power. Blower motor
should run, if it blows the fuse then you have a direct short between R &
G at the board. Do this with R and W(heat) and R & Y(cool).
By disconnecting the thermostat wires and reinserting them make sure that they do not touch when inserted into each terminal. If it still blows
that little 3amp fuse when jumpering between each sequence as mentioned above, then I think your board is bad. When Jumpering out the Y terminal you will have to have the AC wires still hooked up. If it
blows the fuse in that sequence. Disconnect the wires out at the condensor.
red is 24volt power, white is load,I.E. relay,touch the red and wht wires together, the furnace should start, if it don't the problem is the heater, Rheat-Rcool you have a heat/ac thermostat, no ac forget Rc,try turning thermostat all the way up, dig up a multi-meter or powered light tester, touch Rh with one wire of tester,touch the other wire to different terminals until it lights,hook up your wires, you should have heat
Hi, it sounds like you may have a short in the thermostat or in the wires coming from the thermostat. The red and white wires are for heat. If you open the filter door, there should be terminal screws labeled R, W, Y, G and the 4 or 5 strand t-stat wire going to it. Just disconnect the W wire and replace the door, if the heater stays off you have a short somewhere in the thermostat circuit. Unless you just replaced the T-Stat recently, a rodent may have chewed through the wire or a nail pierced the wire, or ???, you get the idea. You may need to pull a new T-Stat wire. Good luck and comment back if you have any other questions.
Hi, There are so many safety controls on most heaters that are designed to shut down the heater if something like this were to happen. I have only seen this happen once in 33 years where the residents were gone shopping, and the heater did not shut off. The plants were all dead as were there pet bird. I believe what is happening, if the thermostat is good, you have a wire in the thermostat cable touching together somewhere. The Red wire to the White which will cause the unit to run all the time. I would first turn off the power to heater and pull the cover and the front of the stat off to excess the wires. Take loose the red wire and it should shut off after a time delay. If it does shut off then the thermostat is faulty. If it continues to run and heat, look closely at the wires at the stat to make sure they are not touching together some where. Check at the heater also where the stat wires come in to see if they are touching somewhere. If you can't see anything, take the red wire off at the heater where it terminates to unit and this should stop the unit. If it does you will know that the wiring from the heater to the stat is touching in the wall somewhere. We use an ohm meter to check continuity on the wires to see which ones are touching. If the heater continues to run with the wire disconnected from it, depending on the age of the unit and if it has a circuit board on it, it would have a shorted connection from hot to w or heat. I would say you have a faulty stat and or wiring touching somewhere calling for heat to be on all the time. This is all it can be. Do the checks I have said and keep me posted on how you are doing. I will wait to hear back from you. Good Luck, Shastalaker7
CIRCUIT CARD- -Photocell blue wired go to two terminals marked BLUE PHOTOCELL (any order) -Motor red wire plugs onto terminal marked MTR MAIN, motor white wire plugs into terminal marked WHITE MOTOR. -potentiometer (thing with knob) two white wires plug into terminals marked TEMP SEL -Black wire from switch to terminal marked L1 BLACK -White wire from power cord goes to terminal marked N White -Ignitor (used to be yellow wires) goto terminals marked IGNITOR and IGNITOR RET (any order)
OTHER- -White wire from power cord goes to switch terminal marked 3A , other pigtail of the white wire goes to board as described above. -Black wire from power cord goes to swtich terminal marked 4B
Probably not, take a small piece of wire and open up the furnace. On the control board find the R and W terminal. It's ok to touch the terminals because the door safety switch will be open. Take that small piece of wire and jump the R and W terminals. Then hold in the door switch to see if the furnace starts. It may take 30 seconds or so so tape the switch closed. If the furnace starts you have either a bad thermostat, broken thermostat wire or a lose wire. If it still does not operate, you have a bad circuit board.
make sure the blower is not set on rather than auto or the blower will run all the time. You might want to disconnect the thermostat and test the low voltage circuit to make sure the wires are not shorted