Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-23-2012, 09:52 PM   #1
Newbie
 
Join Date: Aug 2012
Posts: 7
Share |
Default

Wiring Help


Hello,

I just bought a replacement blower motor for my furnace, and I thought I'd be able to do the wiring myself but it's not layed out the same way as my old motor was. My previous blower motor was set to always run, but it would spin up when the AC or the heat came on. My furnace is a lennox (circa 1978 or something lol). This is just to tide us over until the spring when we buy a new furnace.

Here are the wiring diagrams for the motor (the paper was taped to the motor)






Here is the motor, each terminal or post has a number by it. My old motor had HI or LO on it, so these numbers confused me a bit.



Now here are the old wires. I will replace or restrip them so they're not all mangled looking like they are in the picture.




So any help would be awesome. I don't want to connect something wrong and fry the motor.

Thanks.

Lusty is offline   Reply With Quote
Old 08-23-2012, 10:47 PM   #2
Member
 
Houston204's Avatar
 
Join Date: Oct 2009
Location: Texas
Posts: 585
Default

Wiring Help


Post the furnace wiring diagram...

Houston204 is offline   Reply With Quote
Old 08-23-2012, 11:14 PM   #3
Newbie
 
Join Date: Aug 2012
Posts: 7
Default

Wiring Help


Where would this be located? I've looked inside and out and can't find it. Thanks.
Lusty is offline   Reply With Quote
Old 08-25-2012, 12:24 AM   #4
Newbie
 
Join Date: Aug 2012
Posts: 7
Default

Wiring Help


OK so I hooked up the motor and it works - sort of. Since there we're only 2 connectors I put the 'hi' line to the number 1 terminal and the blue to the #4 terminal. The former'lo' connection I taped off and its not hooked up. Ground is hooked up as well.

The AC works fine it fires up the blower motor no problem and turns it off. The heat won't turn the blower on. If I set the blower to manual then I can circulate heat but it still won't control the motor. Having our blower on all the time on high isn't ideal.

Any idea what i can try? There is no wiring diagram on my furnace. Its old and someone added an AC unit to it so there are wires everywhere.

I tried hooking the 'lo' line into the #1 spot but the motor w
Wouldn't turn on. I'm thinking it might be neutral/negative? Should I combine it with the blue wire?

Thanks guys
Lusty is offline   Reply With Quote
Old 08-25-2012, 04:06 AM   #5
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,600
Default

Wiring Help


the new motor is single speed HI only with 2 wires landing on those terminals the heating and AC are 2 different speeds..keeping in mind the heating supply fan runs thru the furnace heating cycle not the stat.how many wires did the old motor have on it?
biggles is offline   Reply With Quote
Old 08-25-2012, 08:32 AM   #6
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,389
Default

Wiring Help


The low line should run the motor for a heat call. So when you had it connected, did you run the furnace in heat mode? If not, try it in heat mode. If it works in heat mode, you will need to combine the high and low wire both to terminal 1. Using a pigtail is easier then putting both wires on one terminal.
beenthere is offline   Reply With Quote
Old 08-25-2012, 10:10 AM   #7
Newbie
 
Join Date: Aug 2012
Posts: 7
Default

Wiring Help


The old motor was a variable speed. The picture of the wiring above shows where the old wires went. I tried to combine both the hi and lo wire but it just blows the breaker.

Yes when it was connected previous it ran in heat mode perfectly. The AC worked as well. I don't think it's the fan limit controller.
Lusty is offline   Reply With Quote
Old 08-25-2012, 10:14 AM   #8
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,389
Default

Wiring Help


Your old motor was a 2 speed, not a variable speed.

Use a multimeter, and check each wire to ground for voltage. Yiou'll need to turn the fan to on to check the high speed wire, and then you'll need to run the heat to check the low speed wire.

Also, trace out each wire to its source.
beenthere is offline   Reply With Quote
Old 08-25-2012, 04:23 PM   #9
Newbie
 
Join Date: Aug 2012
Posts: 7
Default

Wiring Help


Ok I will track down a multi-meter and check back. Thanks.
Lusty is offline   Reply With Quote
Old 08-25-2012, 06:51 PM   #10
Newbie
 
Join Date: Aug 2012
Posts: 7
Default

Wiring Help


Ok so I managed to get it to work (sorta). I hooked up the old HI line to the #1 terminal and the old LO to the #4. I changed my fan setting to "on" on the thermostat upstairs and started the heat up. I can see the Fan Limit Switch rotate as the furance is heating up and the blower motor fires up after a minute or two. The problem I'm having now is once the blower motor kicks on immediately the burners turn off. I have my limit switch set to 90 / 130 / 200. These are the recommended settings for my limiter. It's like the fan isn't turning on when it's suppose to and the limit switch is turning off for safety...at the same time the blower motor comes on. So now I'm really confused. I'm not worry about the AC working this year, it's going to be winter soon anyway.

Any ideas?

Last edited by Lusty; 08-25-2012 at 06:54 PM.
Lusty is offline   Reply With Quote
Old 08-25-2012, 07:15 PM   #11
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,389
Default

Wiring Help


Some where long the line, the furnace was miss wired. Would need to kn ow where ll the wires go to.
beenthere is offline   Reply With Quote
Old 08-26-2012, 06:33 PM   #12
Newbie
 
Join Date: Aug 2012
Posts: 7
Default

Wiring Help




So here is the fan limiter wiring. The old furnace blower was set to run all the time, on low speed. I can force the fan on by selecting "auto" on my thermostat and the fan runs constantly. It doesn't shut off. I can leave the fan running 24/7 and get heat but it's less than ideal. If I turn the thermostat to "on" it shuts the fan off and it won't come on when it's suppose to.

Here is the picture of the other wiring. I'm not going to open it up and take a picture until I get a multimeter and ensure I don't get shocked.

Lusty is offline   Reply With Quote
Old 08-26-2012, 07:01 PM   #13
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,389
Default

Wiring Help


The blue wire should run to the fan relay and go through the normally closed contacts, and the black wire for high should be on the normally open contacts. Since you now have a single speed blower, you will need to pick the blower speed you need that will be good for both heating and cooling. And then up the fan relay so that the fan limit or the fan relay can bring the fan on.

beenthere is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Attic wiring - ceiling lighting uses 14/2 cable without ground darlingm Electrical 3 11-29-2011 09:01 AM
Backyard wiring questions MikeInDetroit Electrical 1 11-02-2011 09:46 AM
Cloth Wiring - Replace? JessicaGus Electrical 9 09-23-2009 06:45 PM
Replacing wiring in middle of run, ungrounded lighting circuit alexz Electrical 3 07-05-2007 08:53 PM
Knob & Tube wiring - How concerned should we be? hotdiggitydog Electrical 6 04-11-2006 07:52 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.