control and wiring help

troubled

bought used funace for garage, it is old circa 60 or 70's, lennox model GH5-135M1. Have a direct power supply, 110, I hard wired the fan to ensure it worked, and it does there is a transformer, limit switch, fan blower control and gas valve. The wiring seems incomplete. Need assistance on wiring controls correctly. Power in, where does it go from there? Smpler the better, make it "Barney style" for me please, such as step by step or wire by wire, ie; black wire to terminal (?), white wire to terminal (?) thanks for any and all help.

Tim McElwain

Here we go

Are you sure the heat exchanger on this unit is good. If it is cracked it can be dangerous and possibly have carbon monoxide issues.



You need to run 120 VAC 3 wire  14 gauge 15 amp circuit breaker from the panel uninterrupted  to the unit/ Black wire is hot and breaks through the service switch mounted on the furnace. White wire is neutral and bare copper wire is ground (attached to the chassis of the furnace).



You come out of the service switch with 120VAC (Hot Black wire) and power the primary side of the transformer, the other wire on the transformer is attached to the white wire (neutral) this is all best done in a junction box mounted on the unit.



You also have to take the black wire and wire it through the fan side of the fan/limit control and then to the fan motor and the white wire is neutral.



Now a question for you before we move on. Is the fan control and limit control separate or are they a combination control and what are the make and numbers on the controls?



I would say to you if what I just presented to you is blowing your mind then STOP and call a pro.

troubled

thanks

Thanks Tim, yes the echanger is good, the blower control and limit switch are seperate. There are two 14g wires from the transformer one is already hooked to the limit on terminal 4, it is mounted vertically four being the top one. the fan blower control is numbered 1,3,2,4, . 4 has a jumper to the bottom (1) of the limit. the transformers two wires are black and white, for this, I ignore the colors correct and connect the incoming black to the transformer white? thanks

Tim McElwain

NO the black hot goes to the black wire on the transformer

Try sending me some pictures of these controls or at least give me Make and Model number.



the blower control and limit switch are separate. YOU MEAN THEY ARE SEPARATE CONTROLS? 



There are two 14g wires from the transformer one is already hooked to the limit on terminal 4, IS THAT FROM THE SECONDARY OF THE TRANSFORMER OR THE PRIMARY?



it is mounted vertically four being the top one. the fan blower control is numbered 1,3,2,4, . 4 has a jumper to the bottom (1) of the limit.THIS TELLS ME THAT PERHAPS THE LIMIT IS WIRED ON 120 VAC? IT IS INTERRUPTING THE PRIMARY IF THE FURNACE REACHES LIMIT SETTING IS THAT CORRECT?





 the transformers two wires are black and white, for this, I ignore the colors correct and connect the incoming black to the transformer white? thanks NO BLACK HAS TO BE HOOKED TO BLACK AND WHITE TO WHITE.

troubled

more

yes the blower control and limit switch are seperate controls, one transformer and gas valve model is a lennox GH5-135M1, there are two smaller guage wires on the transformer as well, secured on external terminals, one is hooked to the gas valve, other is white and not connected to anything

troubled

pic

here is a pic, i hope i did it right

Tim McElwain

Sorry no

picture came through. Try e-mailing to me at gastc@cox.net

troubled

pic

sent as MMS from phone, thanks again

Tim McElwain

I really can't tell much from the pictures

this I will say those controls are very very old. What I recommend you do is look at getting new controls and have an electrician come and wire it up for you.



I personally would not put something like that old a system in.