DIY Home Improvement, Remodeling & Repair Forum > Appliances > HVAC > "Fan on" option on thermostat not working


Reply
 
Thread Tools Search this Thread Display Modes
Old 06-12-2014, 12:10 AM  
Emac
Junior Member
Join Date: Jan 2014
Posts: 11
Liked 1 Times on 1 Posts

Default "Fan on" option on thermostat not working

Trying to figure out why the "on option" for fan only on thermostat is not working. We moved in this house in december, so we only used the heating so far. The house is quad with 2 furnaces and 2 ac units. Since is not hot enough for ac i just tried to use the fan only option, so i put the heat and ac on off. One fan works, one doesn't, but the ac works on both units. We checked the wires on the wall, for the thermostat, they are all conected. Any sugestions? By the way, my hubby turned the pilot light off, for both furnaces, i don't know if it has anything to do with that.


Emac is offline  
 
Reply With Quote
Old 06-12-2014, 05:42 AM  
kok328
Supporting Member
HRT_SUPPORTER.png
Join Date: Nov 2007
Location: Grand Blanc, MI
Posts: 2,397
Liked 159 Times on 135 Posts
Likes Given: 72

Default

Set the thermostat well above or below the current temp using either heat or cool mode. Then try the "ON" for the thermostat. If this doesn't work then it might be that they didn't wire in the fan.
I can tell you more if you can answer the following:

How many wires are attached to the back of the thermostat(3,4,5)?
What colors are the wired attached to the back of the thermostat (red, green, white, yellow, black)?
What terminals are they attached on the back of the thermostat (R,C,Y,W,Y1,W2,G, etc...)?
Same information as above but, this time we want to look inside the air handler where the thermostat wires connect.


kok328 is offline  
 
Reply With Quote
Old 06-12-2014, 08:15 AM  
Emac
Junior Member
Join Date: Jan 2014
Posts: 11
Liked 1 Times on 1 Posts

Default

There are 4 wires, white, blue, green and red, all conected.
White conected at W, blue conected at Y, green conected at G, and red at R.
Was the blue suppose to be conected at B?
I cannot try the fan with the heat, since the furnace is off, pilot is off too. But it seems the fan works with the ac. But if i put the thermostat on off and put the fan on, nothing happens.
Thank you
Emac is offline  
 
Reply With Quote
Old 06-12-2014, 11:25 AM  
Wuzzat?
Banned
Join Date: Jan 2010
Posts: 2,328
Liked 168 Times on 155 Posts
Likes Given: 94

Default

Almost certainly you'll need a multimeter and a schematic. And sometimes the stat wires change colors inside the wall.

To test the stat independently of the system you'll need a 24 vac transformer and load [like a resistor from Radio Shack]. The stat is just switches controlled by temperature and the user's wishes.

If you just screw around with the wires you could damage something but you may not know it.
This is more confusing than house wiring but mistakes with these systems don't usually cause globs of molten copper to become airborne.

Last edited by Wuzzat?; 06-12-2014 at 04:42 PM.
Wuzzat? is offline  
 
Reply With Quote
Old 10-08-2015, 08:09 PM  
Emac
Junior Member
Join Date: Jan 2014
Posts: 11
Liked 1 Times on 1 Posts

Default

Why is the fan working with the AC but not by itself, or "on" option?
Emac is offline  
 
Reply With Quote
Old 10-11-2015, 03:06 AM  
WyrTwister
Member
Join Date: May 2014
Posts: 79
Liked 11 Times on 10 Posts

Default

Look at the furnace & find those thermostat wires . You should also have small wires from the furnace to the condenser unit , outside .

Look to see if all is well , there . All the wires securely connected to their respective terminals / or wires .

This will be much simpler if you have a volt - ohm meter ( multi-meter ) . You can get one at Home Depot / Harbor Freight , that will do for this , for around $ 10 .

God bless
Wyr

Last edited by WyrTwister; 10-12-2015 at 05:09 AM.
WyrTwister is offline  
 
Reply With Quote
Old 10-11-2015, 09:24 PM  
slownsteady
Supporting Member
HRT_SUPPORTER.png
 
slownsteady's Avatar
Join Date: Jun 2009
Location: Newton, NJ
Posts: 4,159
Liked 632 Times on 530 Posts
Likes Given: 1032

Default

Always check the simple answer first. Does the Tstat have batteries? Are they fresh?
__________________
Learn something every day
---
SnS
slownsteady is offline  
 
Reply With Quote
Old 10-12-2015, 05:08 AM  
WyrTwister
Member
Join Date: May 2014
Posts: 79
Liked 11 Times on 10 Posts

Default

I think the OP said there are 4 wires to the tstat . Works OK for a mercury bulb tstat .

You are right , an electronic tstat would need batteries , since no common wire .

I guess I figured , batteries , if present , would have been replaced before the OP got on the internet ?

Yea , I know ......

God bless
Wyr
WyrTwister is offline  
 
Reply With Quote
Old 10-13-2015, 07:01 PM  
Emac
Junior Member
Join Date: Jan 2014
Posts: 11
Liked 1 Times on 1 Posts

Default

I'll ask my husband to look at all the answers, thank you.
What i can tell you so far is that the problem is not the tstat. We have 2 furnaces, so we moved the tstat from furnace1 to furnace2, and it works fine and we put a Nest at furnace1, and we got the same problem.
So, the problem is at unit 1, the fan works with the furnace or AC, but if i want to use it by itself to just circulate the air, i got nothing.
Emac is offline  
slownsteady Likes This 
Reply With Quote
Old 10-14-2015, 05:31 AM  
WyrTwister
Member
Join Date: May 2014
Posts: 79
Liked 11 Times on 10 Posts

Default

My guess is the problem is with the green wire , from the tstat to the furnace .

You can verify that by putting the tstat to fan - on and measuring from the green at the furnace to common .

God bless
Wyr


WyrTwister 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


Similar Threads
Thread Thread Starter DIY Home Repair Forum Replies Last Post
Difference between "baseboards" and "moulding" panzerfaust0 Walls and Ceilings 8 01-18-2012 02:55 AM
System running Hot while set to "Cool" & "Off" halogen49 HVAC 7 03-06-2011 05:42 PM
Furnace not shutting off when thermostat switched to "heat" rasilun HVAC 1 01-06-2010 03:12 PM
Totaline thermostat blinking "Heat On" before the fan comes on. Maybeitwillwork HVAC 1 01-24-2009 10:20 PM
"Giant" hot water tank stoped working Xilbus Plumbing Forum 3 04-30-2008 06:48 AM