Is my furnace/central air wired correctly??

cjbeck71081

I have a furnace and central air conditioning. I had a contractor renovate the basement and in doing so, he removed (2)sets of 3 color thermostat wire(Red Green White) and replaced the wire with (1)set of 6 wires. When he looked at the control board on the furnace he noticed that the wiring seemed off. It didn't look like it was wired the way it was supposed to, so he told me when hooking up the new thermostat wire, to make sure that the control board is wired correctly.

So, a few months ago, my mother in law, in all of her glory, decided to install a thermostat while I was out of the house and confirmed the contractors thoughts, that the system was wired incorrectly, because she subsequently blew the transformer and control panel at a minimum.

I purchased a new control panel, and am ready to wire up the thermostat according to the way it is supposed to, but I thought I would make sure, that the rest of the system was wired properly before I do.

The pieces in question are the 2 relays, and the fan timer. I have no idea how these are supposed to be wired, so it's hard to say whether they go to the control box the right way. I wonder if anyone had the ability to look at this wiring diagram(which I drew from what is currently there) with all the information, and tell me from their experience if this is wired correctly.

Thank you in advance for your time!

Missouri Bound

First question....did it work properly before the installation of the new stat? More fuses and control boards are blown from people installing thermostats without shutting off all power to the control board. And doesn't your furnace have a wiring diagram right on one of the panels, or perhaps inside the furnace? It's more likely that a short blew out the control board. Did the contractor change the wiring on the furnace?

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cjbeck71081

Thanks for responding so quickly. Yes the system worked just fine before the wiring to the thermostat changed. Even after the contractor came, I had hooked up the white and red wires(used for the heating system) to a simply two wire thermostat to manage the heating system. When the warm weather hit, my mother in law took it upon herself to wire in another thermostat, and YES, without turning off power to the control board. Once she did, the blower stayed on all the time, regardless of what the temperature was set at and the cooling system wouldnt kick on anymore.

I had my uncle who is an electrician come in and test the board, and he said it was fried. He is coming by tomorrow to put in the new board, and I'm trying to avoid blowing it again.

I looked on the panel, and I found a wiring diagram. THANKS!!(I guess that was easy) I'll look it over to see if it matches.

cjbeck71081

Here is the wiring diagram on the back of the panel. From what I see here, it looks like quite a bit of it is backwards.. but I'm not sure. If you have any thoughts, I appreciate it!

cjbeck71081

I spent some time looking at the wiring diagram on the back of the panel. Thanks for suggesting that! It appears as though most of it is wired properly... however the wires that are going from the control panel... are way different than the ones that are on the wiring diagram. Is this common? Or is this a signal that something is wrong.

Currently

Black wire goes from the C on the fan timer to the C on the control board
Blue wire goes from the R on the fan timer to the Y on the control board
Green goes from the G on the fan timer to the G on the control board
White goes from one leg of the heat/cool relay to the W on the board
Red goes from the other leg of the heat/cool relay to the R on the board

^--- This makes more sense to me than the panel suggests, as all the letters match up.(Which could indicate that the contractor moved all them all around even though they werent supposed to be)

Suggested

Black wire goes from one leg of heat/cool relay to the C on the board
Blue wire goes from the G on the fan timer to the W on the control board
Green wire goes from other leg of heat/cool relay to the G on the board
White wire goes from C on the fan timer to C on the control board
Red goes from R on the fan timer to R on the control board

Any ideas as to which one is correct?