Frigidaire/Nordyne Dual Fuel

lweford

I have a Nordyne/Frigidaire Dual Fuel packaged 4 ton unit paired with a IAQ Pro Honeywell Tstat that says it will handle 2 stages of cool and 4 stages of heat. From the factory the unit comes prewired for high fire only when Aux Heat is called for. The installation manual clearly shows how to wire gas valve for low fire and high fire use. When I wire it like the manual says the burner will fire up but the blower motor never starts which in turn allows the unit to limit out for heat. Wire it back up for high fire only and blower starts just fine when burners lite. At this point I would normally call a dealer that specializes in Frigidaire but there are none within 200 miles of my area. Does anyone know what I am missing? Is it a Tstat issue or unit issue? Thanks in advance for your help.

JUGHNE

When you say packaged does this mean it is one self contained unit with duct work connected?

lweford

Yes it has ductwork connected with a return.

JUGHNE

So the whole thing sits outside....That explains why it isn't in the Frigidaire Dealer book.
Did you try it on emg heat only, raising temp one degree?

John Mills_5

In typical Nortek fashion, they do some weird stuff. I found 2 drawings in their manual. The one shows wiring W1 and W2 straight to the main board. The other shows wiring W1 to the defrost board and W2 to the main board.

If you are putting 24v into W1 and the furnace fires but the board never brings on the blower, it is the board bad.

You're not messing with the wiring to the gas valve are you? That should come off the board and not be touched.

lweford

Wanted to let you know I figured out the problem. It looks like from the factory that a jumper was missing from the low side of the gas valve to the variable speed fan board. Specifically terminal "W" on fan board. After adding this jumper from terminal "W" to the low side of gas valve all is working as it should. I finally noticed on wiring diagram that I did not have said jumper and then went and looked at an identical unit like mine and saw that that unit had the jumper and was hooked to low side of gas valve with a piggy back male spade. As there is already a jumper from furnace board to low side of gas valve. Both have to be connected there. Thanks for everyone's help and input.