Author Topic: Payne PG95XAT - "y" connection question  (Read 498 times)

Offline Grant F

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Payne PG95XAT - "y" connection question
« on: May 23, 2018, 07:44:49 AM »
Hi,
I just had a Payne PG95XAT 2 stage furnace installed and want to know what terminal should the "y" wire from my thermostat be connected to on my furnace board. The board has a "y1" and a "y/y2" terminal. The a/c unit is a single stage. The thermostat is a single stage - 4 wire. I know that connecting the "y" wire to either terminal on the board will work, but the Payne installation manual suggests to use the "y/y2" terminal on its board. They don't explain why. Do you have any idea why the preference to use "y/y2" over "y" ?
Thank you

Offline Sergroum

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Re: Payne PG95XAT - "y" connection question
« Reply #1 on: May 23, 2018, 08:01:33 AM »
It should be y/y2.

Basically this furnace has a dip switch that indicates what kind of a thermostat you're using. If you're using a single stage thermostat (and you are, if you've got 4 wires) then the dipswitch is in one setting and you're hooking up the wire to y/y2. This will activate the highest stage of cooling right away, or if you set the setting right, would start at low stage and then kick it automatically up to higher stage after 7-15 min. (This is not default. Nor do you need it to be, since you've got a 1 stage cooling anyway)

If you were using a two stage thermostat. Then you would've hooked it up y1 to y1, and y2  to y/y2 and then set the board to use 2 stage thermostat mode of operation.


As of right now. y/y2 setting is basically  y1 and y2 with a jumper across it.


Long story short. Set it to y/y2.

Offline Grant F

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Re: Payne PG95XAT - "y" connection question
« Reply #2 on: May 23, 2018, 08:00:21 PM »
Hi Sergroum,
Thanks for the excellent response. However my unit doesn't have a set of dip switches that select a two stage or single stage thermostat. The only set of dip switches are for;
Low heat only, or norm heat (dip sw 1)
Blower off delay - combination of (dip sw 2 and 3)
This unit has built in adaptive heating, and cooling algorithms for thermostats that are single stage.
Thank you

Offline Admin

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Re: Payne PG95XAT - "y" connection question
« Reply #3 on: May 23, 2018, 08:47:14 PM »
If you wired the AC to Y1 you’re furnace fan would be running at a low speed, for low stage cooling (2 stage AC).  Y/Y2 will enable the high speed fan, which is what you want.  Both the thermostat and AC should have a wire connected to Y/Y2.

If you had more thermostat wires and a 2 stage thermostat you would turn the SW-1 LHT to ON.  This would tell the furnace you’re using a 2 stage thermostat for heating.  This dip switch has no affect on the cooling stages.

To enable 2 stage cooling most manufacturers require you to cut or disable a jumper on the board.  On your furnace it’s called the ACRDJ jumper.  If you disable that the furnace knows you’re using a 2 stage AC and thermostat.  You can leave the ACRDJ jumper in place and still use a 2 stage air conditioner and wire both Y1 and Y/Y2, and the board would control the cooling stages.

Offline Grant F

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Re: Payne PG95XAT - "y" connection question
« Reply #4 on: May 24, 2018, 08:23:31 PM »
Thank you for your excellent explanation.
Upon closer inspection of the wiring done by the installer, I quickly realized why there was no difference in blower fan speed connecting the y wire from either the y1 or the y/y2 on the furnace board. The reason was - he forgot to connect the other end of the orange wire (y1 or y/y2) to the tstat's y wire. Therefore all that was happening when I turned on the air conditioner with the tstat, was it was directly turning on the fan and the a/c coil from the tstat only. Once I connected the tstat's y wire also to the y/y2 terminal, via the orange wire, on the board, then the blower fan speed ran as it should, controlled by the board, on the cool speed setting.
Thank you.
Grant