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-   -   luxaire/york 33109167000 furnace board replacement (http://www.diychatroom.com/f17/luxaire-york-33109167000-furnace-board-replacement-48460/)

check 07-09-2009 10:18 AM

luxaire/york 33109167000 furnace board replacement
 
I had to replace my 7 year-old furnace board ("ignition control unit"), which is an updated board that has an extra Y terminal for the Thermostat and AC relay wires. (The old board had only one Y terminal, and the new one has 2 because it will work for a 2-stage system as well as my one-stage system.) the furnace worked fine, but when it came time for AC, nothing. I found out I was supposed to connect both the Thermoststat Y wire and one of the (24 volt) wires going outside to the AC unit, to the "Y/Y2" terminal on the new board. (I was told that the other Y terminal - labelled "Y1" - did not apply to my one-stage system.) So, I did that, and then the AC compressor outside would come on when I switched the thermostat to "cool", but the main furnace blower would not come on to circulate the air through the house.

Well, after many calls to service people (including the Unitary products home office in Oklahoma and the York/Johnson Controls people here in Oakville, Ontario), I was told to switch one of the 110 volt wires on the board. Specifically, I was told to change the black wire from "LO COOL" to "HIGH COOL", which I did. (Note that this 110 volt black wire also had a jumper wire which was connected to the "HEAT" terminal.) So now the furnace fan comes on nicely when I set the Thermostat to "cool", but the AC compressor outside no longer comes on!

I aslo bought another new board in case the first new one was now defective, and I found a small u-shaped wire in the box, which was bent to just the right size to serve as a jumper across two adjacent 24-volt terminals on the board, but which two? (They are labelled Y1, Y/Y2, W, R, G, and C, in that order.) And why did I not find this little wire in the box with the first new board that I bought? And why was there no reference to this wire in the instrction that came with the new board? Also, the box on the second new board had obviously been opened and retaped closed, so perhaps somone else had already tried the board and perhaps it was even a returned board, so perhaps the previous "owner" had simply fashioned this little jumper wire from a piece of thermostat wire - if so, for what purpose?

I'd really appreciate any help anyone could give me, because the technician at the Canadian head office in Oakville went over things with me on the phone and said that, based upon my description, everything should be working fine. Help!:(

beenthere 07-09-2009 12:09 PM

Are you sure you didn't knock one of the low voltage wires loose to the outdoor unit.

The board has no control over the outdoor unit.

Since you wire one of the 2 wires from the outdoor to the C terminal, and the other to the Y/Y2 terminal with the wire from the thermostat.

check 07-09-2009 03:04 PM

Quote:

Originally Posted by beenthere (Post 299508)
Are you sure you didn't knock one of the low voltage wires loose to the outdoor unit.

The board has no control over the outdoor unit.

Since you wire one of the 2 wires from the outdoor to the C terminal, and the other to the Y/Y2 terminal with the wire from the thermostat.

No, all wires are tight, and one thing I did not mention is that the new board shows a yellow 110 volt ("Medium-Low) wire coming from the furnace blower, which I do not have.

beenthere 07-09-2009 03:13 PM

The board doesn't control the outdoor unit.

Connect the wire from the outdoor unit that goes to the Y/Y2 to the R terminal of the board. Turn power back on.
If the outdoor unit runs. Your thermostat is mesed up.

If it doesn't run. Your C terminal on teh furnace board may have a bad connection to the board.

check 07-09-2009 03:55 PM

Quote:

Originally Posted by beenthere (Post 299561)
The board doesn't control the outdoor unit.

Connect the wire from the outdoor unit that goes to the Y/Y2 to the R terminal of the board. Turn power back on.
If the outdoor unit runs. Your thermostat is mesed up.

If it doesn't run. Your C terminal on teh furnace board may have a bad connection to the board.

Couldn't I just measure the voltage across the C and R terminals, and see if we do in fact get 24 volts? And why does the manual say that during a call for cool, a circuite is created between the G, R, and Y (persumably the new Y/Y2) terminals?

beenthere 07-09-2009 04:03 PM

You can check voltage acroos R and C.

Because it does.
But only when the thermostat calls for cooling.

The indoor fan didn't run the first time, because you had the blower wire on the wrong blower tap.

When you moved that wire. You distrubed something that the outdoor unit doesn't run anymore.

check 07-09-2009 04:28 PM

Well, I did check out the wiring connections, and will do it again when I am up there tomorrow, but I really think it has something to do with the 110 volt terminals, whereby the installation instructions for the new board call for a yellow "MED-LOW" wire to be connected to the LO COOL terminal, and the Blue "MED-HI" wire to be connected to the "HEAT" terminal. (I have no yellow wire, so I suspect this connection is intended for 2-stage furnaces, whereas mine is a one-stage model.)

In the manual for the furnace, it says that you can just attach the black (HI) blower wire to both the "HI-COOL" and "HEAT" terminals if you want both the heating and the cooling fan speeds to be high. However, as I mentioned above the new board instructions show the Yellow wire connected to "LO-COOL" , the black wire connected to "HI-COOL" , and the Blue wire connected to "HEAT", while a fourth wire (Red) is parked on one of the "PARK" terminals.

beenthere 07-09-2009 04:38 PM

The 110 volt has nothing to do with the outdoor unit running.

The board is an upgraded board, and is also used on newer furnaces that come with a 4 speed blower instead of the 3 speed blower your furnace came with.

Has nothing to do with weather or not your outdoor unit runs.

check 07-09-2009 05:02 PM

beenthere, I do appreciate your help, and I appreciate that this thread must be a bit frustrating for you. (Indeed, this whole experience with this $%*$#@ furnace has been very frustrating for me, as I cannot get a straight answer from either the techie's nor the local service people, and the furnace has been screwing up a lot (e.g., the pressure switch went in the middle of winter).

I will check the connections again tomorrow, and then try switching the 110 volt terminals back the way they were, to see if my AC unit goes on again (which would surprise the heck out of you, I guess).

Will you be on this forum tomorrow, so I can report back to you?

Thanks,

James

beenthere 07-09-2009 05:07 PM

What time I can't say.

Recheck ALL low voltage connections a gain.
A wire could have broken inside its insulation, then it looks to be connected, but won't work because it broke inside.

check 07-09-2009 05:18 PM

OK, will do. Will also recheck the continuity of the wires to the Thermostat and out to the AC unit. I also have another Thermostat I can hook up, to make sure that is not the problem.

dac122 07-09-2009 06:55 PM

Alternatively, if your tstat energizes G during cooling, just disconnect Y and Y1 from the furnace board and make sure the Y terminal on your tstat runs all the way out to outdoor unit. Just disconnect yellows off the furnace board and throw a wire nut on it. It would not be unusual for Unitrary products and the board manufacturer to not know how it all works. I've experinced that before.

beenthere 07-09-2009 07:51 PM

Its not a problem with the board. It was a miswire.

And probably a broken LV wire now.

check 07-09-2009 11:01 PM

Quote:

Originally Posted by beenthere (Post 299698)
Its not a problem with the board. It was a miswire.

And probably a broken LV wire now.

What's an LV wire?

beenthere 07-10-2009 05:03 AM

Low Voltage


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