Replies

1. 
   NPitz | Jun 06, 2002 01:55am | #1

   I don't know that I will be able to help either, but I think that anyone who can help is going to need more detailed description of the wiring. How many wires go to each thermostat, and how does the outdoor thermostat figure in? You should be able to determine if the outdoor thermostat is functioning by doing a continuity test on it when it is disconnected. Also, you should be able to get a copy of the wiring diagram either off the inside of the unit or from a local distributor. Does it show the second relay?

1. 
   barnee | Jun 06, 2002 02:19am | #3

   Thank's for replying! First I'll tell you that when I went to wire the new stat wire in the old wires were just twisted together by hand so I have no reference as to how it was set up. My thermostat wires come in and are attached as follows Blue wire to (T) green wire to (G) white to(W) and red to(R) this appears to counterdict the schematic which says that Y which isn't used is supposed to go to the compressor contactor. One wire from my old heat thermostat goes to the relay tab#2 the other wire from the therm goes to(R) on the board. Also on the outdoor therm, there is continuity between R2 &Y2 but none between R1&Y1. I also looked at the schematics earlier and there is no sign of that relay, it is mounted to the acess door to the blower. The only thing I hope to get straight is whether or not I should just start over and if so which wires should go where? Thanks alot.

1. 
   NPitz | Jun 06, 2002 01:41pm | #5

   OK - Again, I don't have specific information on your model, but the general wiring scheme for most furnaces is a five wire scheme - the connections at the furnace are generally Rh (red - heating), Rc (blue - cooling) white (common - oftentimes heat only), yellow (common - usually to compressor), and green (fan).

   Now, does the heating thermostat have a fan control? It doesn't sound like it. A TYPICAL connection would be a two wire from the heating thermostat going to Rh and White. If this thermostat closes, the heat comes on. Theoretically you could check this by jumpering the Rh and white terminals inside the unit (but I would not advise you to do this, since if you are wrong you could fry it).

   Then, TYPICALLY, there is a three wire connection from the A/C thermostat. Blue goes to Rc (usually the terminal on the thermostat is marked Rc also). Green goes to the fan control. NORMALLY yellow comes from the thermostat, gets spliced to one leg of the two wire going to the compressor, and the return leg from the compressor goes to the yellow terminal or connection in the unit. When the thermostat calls for cooling, it closes the circuit between Rc and yellow, activating the contactor on the compressor and also turning on the furnace.

   I have no idea how an outdoor thermostat figures into this, and I have no idea how the "extra" relay figures in. Somebody posted that it is a direct vent furnace, so keep in mind that there may be extra wiring in there such as a "proving" circuit that confirms that the direct vent is working before the heat will fire up.

   Good Luck, and be careful, it's not hard to fry a control or a transformer (I know, I've done it) and you don't want to slug the compressor either.

1. 
   barnee | Jun 07, 2002 02:21am | #6

   I just got your message today and went to the thermostat to see how it was wired, and found out that I had wired blue wire from furnace to B on thermostat. I moved the blue wire to the Y on the thermostat and now everything works! Thanks a ton for your schematics(and explination) because they say that we'll be near 90 here in MI this weekend.

1. 
   NPitz | Jun 07, 2002 06:01am | #8

   Glad to hear it worked out.

2. 
   BillHartmann | Jun 06, 2002 02:07am | #2

   What kind of furnace is it? Do you have a heat pump and maybe the thermostate is used to switch from heat pump to backup?

1. 
   barnee | Jun 06, 2002 02:23am | #4

   It's a Lenox pulse about 9 years old. Gas fired forced air furnace. I believe that this is one of the first generation direct vent models. It,s been great the only thing thats  gone wrong was about two years ago the smart board went bad and I had to replace it.

3. 
   oldlou | Jun 07, 2002 04:41am | #7

   Did you know that the early Lenox pulse units had a recall on the stainless steel heat exchangers? From what I recall the exchanger would split and allow burner exhaust gases to enter the heating system supply air and thus the residence. Problem? Carbon monoxide poisoning? Do you often get head aches in the winter?

   
   

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   Edited 6/7/2002 9:47:23 AM ET by OLDLOU

1. 
   UncleDunc | Jun 07, 2002 09:51am | #9

   Lennox?