Fan Limit Switch Question - HVAC - DIY Chatroom Home Improvement Forum


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

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

Reply
 
Thread Tools Display Modes
Old 11-01-2011, 12:23 PM   #1
Newbie
 
Join Date: Nov 2011
Posts: 4
Rewards Points: 10
Default

Fan Limit Switch Question


Question for the experts regarding Honeywell fan limit switch:

in observing the movement of the dial during heating cycle, my dial does not move smoothly and slowly.....example: during cooling, the dial seems to get stuck on a temperature of say 100 degrees , then 'jumps' to 80 degrees to stop the fan.

Is this normal, or time for a new switch?

Advertisement

hr2pilot is offline   Reply With Quote
Old 11-01-2011, 12:30 PM   #2
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,630
Rewards Points: 2,000
Default

Fan Limit Switch Question


the pigtail is going when it cools or the switch might be weak breaking cheap change out from local GRAINGER there #2E820 the range and pigtail lenght is the thing to not on change out...how does it do heating up from 80 to 100+ the burner heat is on the tail but might be working into the contacts....

Advertisement

biggles is offline   Reply With Quote
Old 11-01-2011, 12:57 PM   #3
Newbie
 
Join Date: Nov 2011
Posts: 4
Rewards Points: 10
Default

Fan Limit Switch Question


hi biggles....

Ok, I just ran it through a heating cycle, it rotates slowly as heat increases.

If I tap the side of the switch with my finger, it will jump a bit, not as much as on the cooling.

Can the switch mechanism be cleaned or lubricated?

By the way, is 130 degree fan kick-in normal....it seem like that's kind of high.???? It takes a couple of minutes to get up to temperature begore high speed kicks in.....seems like a long time to me.

thanks
hr2pilot is offline   Reply With Quote
Old 11-01-2011, 01:24 PM   #4
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,630
Rewards Points: 2,000
Default

Fan Limit Switch Question


it's enclosed as you see with the cover off if you remove the control might snap the silver backing off and do a visual little WD-40 on the contact but it is very low end mechanical just turns and makes the fan or upinto hi limit.if it is stone cold the HEAT-X has to cook up so the pigtail expands and turns to close for fan.might want to go to 140F,but don't know what that HI SPEED is your refering to heating should run LO or Med LO for heating systems.if you don't feel a draft when the air comes out of the registers that is a bench mark for your system as much as a draft after the stat satifies burner off...then the fan cooling down and going off.can't do anything with the pigtail it's just metal heating and coolingNOTE if yo go to slip the controller out try to do it with the wires connected power off
biggles is offline   Reply With Quote
Old 11-01-2011, 03:31 PM   #5
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,543
Rewards Points: 4,724
Default

Fan Limit Switch Question


Not uncommon for them to jump.
beenthere is online now   Reply With Quote
Old 11-01-2011, 03:44 PM   #6
Newbie
 
Join Date: Nov 2011
Posts: 4
Rewards Points: 10
Default

Fan Limit Switch Question


thanks guys...won't hurt to change it i suppose.... furnace is 20 years old and new replacement parts online are pretty cheap to get the whole thing tuned up.
hr2pilot is offline   Reply With Quote
Old 11-01-2011, 03:56 PM   #7
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,630
Rewards Points: 2,000
Default

Fan Limit Switch Question


20 yrs is worth a change out heating and cooling doesn't owe you anything there just for pricing reference shop around... http://www.bestbuyheatingandaircondi.../fan&limit.htm
biggles is offline   Reply With Quote
Old 11-01-2011, 06:21 PM   #8
Member
 
newtech's Avatar
 
Join Date: Mar 2009
Posts: 251
Rewards Points: 162
Default

Fan Limit Switch Question


Quote:
Originally Posted by biggles View Post
the pigtail is going when it cools or the switch might be weak breaking cheap change out from local GRAINGER there #2E820 the range and pigtail lenght is the thing to not on change out...how does it do heating up from 80 to 100+ the burner heat is on the tail but might be working into the contacts....
newtech is offline   Reply With Quote
Old 11-01-2011, 07:38 PM   #9
REP
Member
 
Join Date: Jul 2011
Posts: 615
Rewards Points: 500
Default

Fan Limit Switch Question


It is a 50 year old design and your appears to be working as designed.
There is nothing unusual with a 130 degree cut in for the fan,that is normal too.
If you want it to come on quicker then the register tremature will be cooler.
Suggestion only as long as its working as designed,,,,leave it alone.
REP is offline   Reply With Quote
Old 11-01-2011, 08:09 PM   #10
Newbie
 
Join Date: Nov 2011
Posts: 4
Rewards Points: 10
Default

Fan Limit Switch Question


Thanks for the advice guys!

Great website!

Advertisement

hr2pilot is offline   Reply With Quote
Reply


Thread Tools
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
Trane limit switch mikethe ductman HVAC 7 01-18-2012 11:46 PM
Blower fan won't turn off - limit switch replaced Laplacian HVAC 4 02-14-2011 12:55 PM
Quick Bathroom Plug and switch Question mclemenc Electrical 5 01-30-2011 11:02 PM
fan/light switch buzzing mjlocat Electrical 4 05-23-2010 03:44 PM
Dayton 3E837 Limit Switch Question edanajo HVAC 11 12-04-2009 04:52 AM




Top of Page | View New Posts