So I have a York diamond 80 furnace and the motherboard burned out so Lowe’s came and replaced it. I’ve been using the heater because it’s winter right now but the other day I accidentally hit the cool button on my thermostat and it sounded like something popped so I checked it out the wiring and realized the 3A fuse blew out. But I noticed that the thermostat wiring is different from before Lowe’s installed the new motherboard. the thermostat has (W with W) (G with G) (Y with Y) (R with RC) as it should because they never touched the thermostat but on the mother board of the furnace which is the part that Lowe’s switched out they have (W and G) jumped together and the rest of the colors match with the thermostat before they installed that motherboard I knew that W was by itself and G was by itself I don’t know why they would jump W with G together but can that cause my unit to be faulty
HVAC York diamond 80 furnace A/C
furnaceheatinghvac
Related Solutions
Since you mention an igniter I'm going to assume a gas furnace. So start by turning off the gas. Then disconnect everything else other than the power in and the thermostat wiring.
Now turn on the thermostat. If the fuse doesn't blow, reconnect one thing (like the igniter) and try again. Repeat until something blows the fuse.
Since you have isolated the problem to the igniters, I would try just replacing one or both of them. That's probably cheap to do. If that doesn't work, then you're probably looking at replacing the control board.
There's two ways to wire this up. The first method is to take advantage of the HUM terminal on the furnace control board. This terminal will supply 120 volts when the furnace is running in heat mode, so you'll have to use an additional transformer.
You'll hook the primary side of the transformer to the HUM, and Neutral terminals in the furnace. Then you'll connect the 24VAC terminals of the humidistat, to the secondary of the transformer.
The other method, is to use the furnaces transformer to provide power to the humidistat. However, you'll have to make sure the transformer is large enough to supply the load.
With this setup, you'll connect the 24VAC terminals of the humidistat to the C and W terminals on the furnace control board. That way when the thermostat calls for heat, the humidistat will be powered by the furnaces transformer.
Best Answer
It's definitely wired wrong. You need 4 wires to your stat R to Rc and Rh or R and Rc (it's hard to tell from the picture) bottom line is all three R's go together obviously using the red. W to W using the white. G to G using the green. Y/Y2 to Y using the yellow. That's it! Get that blue one outta there. The other 2 conductor cable is for the A/C one goes to C and the other to Y/Y2