OLD fan control relay issue


  #1  
Old 12-23-04, 04:13 AM
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Question OLD blower fan relay issue

Hi; and thanks for thine advice hence and that already gleaned from this forum; The best i've seen, and with such decorum. Anyway, i have a 50's? era Minneapolis Honeywell (!) Combination Furnace Controller model LA401AX30 - - - 2. Googling this got me nowhere pertinant. It seems to me to be an older model than the blower controllers discussed here of late. It's a box approx. 6"Hx~4.5"Wx2.5"D mounted on the duct directly above the oil furnace. The box has a high limit slider tab on the left, and fan-on and fan-off slider tabs on the right. Upon removing the outer cover, one sees one relay on each side, under their respective limit and fan positions.

So...The problem is that the blower comes on not; or won't shut off. The problem became obvious of late as the blower did not shut off for a week or so and began begging for a lube. The only way that i've been able to get this thing to work at all (especially to turn the blower on) is to set the fan on tab very low (~80F!), and the fan off tab in a position as to bring to mind siamese twins.

Now...I suspect the fan relay to be at fault as i can give it a feathery flick of my forefinger to elicit the desired on or off effect.
Two questions have i. Could the fault possibly be in the fan blower tab temperature-sensing thingies?...

...And second, getting to the point, CAN I DISSEMBLE THIS FAN RELAY? It has the numbers 96-244 on a piece of tape on the front (again googling was of no help). It has what appear to be mounting screws in the upper left and lower right corners. The relay is about the size of one's forefinger two knuckles in from the tip and nearly twice the depth (i'm tall and a bit scrawny). It has a black wire on the top terminal and a whitish wire on the bottom. It has 120v AC between the two until the fan switches on at which point zero is the voltage.

What i am really hoping is that someone in this cyber-furnace will have cracked one of these relays in half and buffed the contacts with some 600 gritish sandpaper or emery paper or some such ridiculousness with some success; i.e., rebuilt the relay. Is this possible?

Or, does anyone know of parts suppliers with vintage or retrofit limit/fan
controllers of the two wire variety?

Do i get the long-winded award?
 

Last edited by relayed; 12-23-04 at 06:20 AM.
  #2  
Old 12-23-04, 06:42 AM
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You should be able to remove it and take it to any hvac supply store to get a new one. They're pretty common and readily available.
 
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Old 12-23-04, 07:12 AM
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but can i take it apart?

I realize that this is not the preferred procedure, but have you seen relays of this vintage that can be fairly easily opened and their contacts cleaned/sanded like those of the points of a VW? The main reason i ask, besides the arse-pain involved w/speaking to my landlord, is that i am fairly certain that inside that relay is a couple of highly corroded contacts that i could make viable again through buffing. What i don't know is whether it is possible to open up these vintage relays or not (without doing damage).

Also, would you reccomend replacing the entire fan/limit control unit or just replacing what i think is the defective relay?
Your response is, of course, and was, very much appreciated. It's comforting to know that someone thinks that these parts are out there.
-still thwacking
 
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Old 12-23-04, 07:50 AM
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If you go into it to try and clean teh points it wont be the same .Forget it get a new one. Any of the honeywell fan limits will work for you. Ask for a L4064B22 What you do want ,is see how long the element on the one you have now and get the same

Also, would you reccomend replacing the entire fan/limit control unit or just replacing what i think is the defective relay?
Get a fan limit control. I dont know what you mean by relay here is it tied to the blower here for a AC or humidifier

ED
 
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Old 12-23-04, 08:24 AM
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by element, do you mean...

by element, do you mean the temperature probe?

The relay i speak of is under the cover plate of the fan high limit/blower switches. There is one relay for each (limit,fan) located beneath the cigarette-pack-though-twice-as-thick sized enclosed housing which houses the high limit and fan-on and fan-off setting tabs. I'm really wishing i had a digital camera right now.

Speaking of temperature probes, while i'm certain that one must be present, i haven't found it and am also not sure where to find the plenum
or if i will be fined by the FCC for saying plenum.

Simple system here; no AC or humidifier, just a furnace.
Again, thanks for the forum!

P.S: By element might you be refering to something measuring something other than the plenum temp like the air duct temp? Is there such an artifice?
 

Last edited by relayed; 12-23-04 at 09:15 AM.
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Old 12-23-04, 08:56 AM
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Availiabilitay

I think that my only other question, and it seems to be implicit in thine answer (mattison), is whether newer controllers are backwards compatible, as it were, with the ancient ones.

Thank you for thine time...
-rewards upon thee trine
 
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Old 12-23-04, 10:19 AM
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What Ed's saying about the element, it's behind the control. When you uncrew it from the plenum and pull it out the element will be 6" - 10' long. That is normally what goes bad. They're not worth fooling with and easy to just replace.
 
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Old 12-23-04, 10:39 AM
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moderate thanks

'tis the first time i've really messed with a forum or thread or even the molecules thereof. Thus i would like to thank the moderators of this one for being. Not to mention the responses. And the responses...
 
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Old 12-23-04, 11:06 AM
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One more thing...

does that mean that the element,and not the blower controller, is the likely culprit? And is that a seperate piece? Or, in other words, is the element integral to the blower fan controller, or is the element a seperate entity that can be replaced on its own?
Was that coherent?
 
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Old 12-23-04, 11:12 AM
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The fan limit control comes as one with the element on it. just be sure and get one just as long as the one you have.

ED
 

Last edited by Ed Imeduc; 12-23-04 at 01:45 PM.
  #11  
Old 12-23-04, 11:45 AM
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you rule ED!

Help here i found nowhere else
to i thine are the christmas elfs!
Thanks!
-scichedelic
 
 

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