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Old 08-17-2011, 07:47 PM   #46
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Blower Motor Wiring reversed?


Quote:
Originally Posted by biggles View Post
one short fan test on that dial isn't going to cause any damage to it if you turned it to trip the gas cycle to check the hi limit maybe..why you scaring this guy into checking his fire insurance....

Gee, I hate to admit it. but, I rotated the dial on several hundred of them already. And none of them ever failed because I rotated them. Found a few that had bad contacts and wouldn't turn on the fan, or the limit contacts wouldn't open up, by testing it that way.

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Old 08-17-2011, 11:04 PM   #47
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Blower Motor Wiring reversed?


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Originally Posted by beenthere View Post
Gee, I hate to admit it. but, I rotated the dial on several hundred of them already. And none of them ever failed because I rotated them. Found a few that had bad contacts and wouldn't turn on the fan, or the limit contacts wouldn't open up, by testing it that way.
"CAUTION
When adjusting the fan and limit set point levers
(Fig. 10), hold the scalepale dial to keep it from turning
and straining the sensing element.
Move each indicator lever to the control point
recommended by the burner or furnace manufacturer.
Use gentle finger pressure
CHECKOUT
When installation is complete, disconnect the fan
motor circuit . Turn on power and set
thermostat to call for heat. Burner should come on and
limit controller should shut burner off when plenum
temperature reaches the limit set point. Turn off power,
recconnect the fan switch, turn on power and again set
thermostat to call for heat. Fan should come on when
plenum temperature has reached fan-on setting."
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Old 08-17-2011, 11:35 PM   #48
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Blower Motor Wiring reversed?


yep. Why worry about a cheap fan limit switch, when we can over heat the expensive heat exchanger.
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Old 08-18-2011, 05:29 PM   #49
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Blower Motor Wiring reversed?


Quote:
Originally Posted by beenthere View Post
yep. Why worry about a cheap fan limit switch, when we can over heat the expensive heat exchanger.
So what you are you saying???

1. The fan and limit is cheap. So if you turn the dial and screw it up, no big deal to change it.
Or

2. If you rotate the dial and it gets out of calibration you could over heat the He!! out of the unit.

If there " WAS " a small crack in the HX, and you were doing a PM on it and just rotated the dial to see if the high limit was working you probably would have not found it.



Most of the HX that used the fan and limit's were pretty tough, so to trip them on the limit without the fan on start up was normal practice to make sure that they worked. We even had to have a temp probe mounted to verify the cut out temp.











There is a check out procedure for just about every product sold in the HVAC world

If you want to vary from this, that is your business.



Just my opinion

Last edited by newtech; 08-18-2011 at 06:36 PM.
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Old 08-18-2011, 06:39 PM   #50
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Blower Motor Wiring reversed?


Quote:
Originally Posted by beenthere View Post
Gee, I hate to admit it. but, I rotated the dial on several hundred of them already. And none of them ever failed because I rotated them. Found a few that had bad contacts and wouldn't turn on the fan, or the limit contacts wouldn't open up, by testing it that way.

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Old 08-18-2011, 08:53 PM   #51
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Blower Motor Wiring reversed?


Quote:
Originally Posted by newtech View Post
So what you are you saying???

1. The fan and limit is cheap. So if you turn the dial and screw it up, no big deal to change it.
Or

2. If you rotate the dial and it gets out of calibration you could over heat the He!! out of the unit.

If there " WAS " a small crack in the HX, and you were doing a PM on it and just rotated the dial to see if the high limit was working you probably would have not found it.



Most of the HX that used the fan and limit's were pretty tough, so to trip them on the limit without the fan on start up was normal practice to make sure that they worked. We even had to have a temp probe mounted to verify the cut out temp.











There is a check out procedure for just about every product sold in the HVAC world

If you want to vary from this, that is your business.



Just my opinion

You ain't gonna harm a Honeywell L4064B fan limit by rotating its dial. Unless its already worn out.
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Old 08-18-2011, 09:25 PM   #52
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Blower Motor Wiring reversed?


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Originally Posted by newtech

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Old 08-21-2011, 11:20 AM   #53
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Blower Motor Wiring reversed?


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You ain't gonna harm a Honeywell L4064B fan limit by rotating its dial. Unless its already worn out.
How does one know or tell if its "worn-out"?
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Old 08-21-2011, 01:16 PM   #54
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Blower Motor Wiring reversed?


First, if it doesn't turn the fan off or on, its worn out. Next, if it doesn't open up the limit contacts its worn out.

I do rotate it to see if the limit opens. I check by running the burner, if it will bring the fan on an d turn it back off. And compare it to my temp probes.
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Old 08-23-2011, 05:29 PM   #55
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Blower Motor Wiring reversed?


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Originally Posted by beenthere View Post
You ain't gonna harm a Honeywell L4064B fan limit by rotating its dial. Unless its already worn out.
Thats not a L4064B in the pic...
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Old 08-23-2011, 05:33 PM   #56
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Blower Motor Wiring reversed?


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Thats not a L4064B in the pic...
Which pic. And what is it then.
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Old 08-23-2011, 05:38 PM   #57
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Blower Motor Wiring reversed?


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Originally Posted by beenthere View Post
Which pic. And what is it then.

Post #31

The L4064B has a manual switch to provide
continuous fan operation.
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Old 08-23-2011, 05:53 PM   #58
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Blower Motor Wiring reversed?


Quote:
Originally Posted by newtech View Post
Post #31

The L4064B has a manual switch to provide
continuous fan operation.
LOL... Your right. L4064 B's, D's, F's, R's and W's have the manual fan on switch.

L4064 A's, J's, T's, and Y's don't. But its still an L4064 fan limit control/switch.

T's, W's, and Y's have a built in heater to assist in bringing on the fan.
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Old 08-23-2011, 06:29 PM   #59
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Blower Motor Wiring reversed?


Quote:
Originally Posted by beenthere View Post
LOL... Your right. L4064 B's, D's, F's, R's and W's have the manual fan on switch.

L4064 A's, J's, T's, and Y's don't. But its still an L4064 fan limit control/switch.

T's, W's, and Y's have a built in heater to assist in bringing on the fan.
We must have the same manual

My only concern is, how he kept the fan running to check the air flow...

Did he turn the dial and lock it in position, hold it for any length of time while someone else checked the air flow.

Just some questions that I would be concerned with.

And I will still state that it needs to be checked out before the heating season. It is a 20yr old unit and if it is the original fan and limit, who knows what might happen... jmo
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Old 08-23-2011, 07:11 PM   #60
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Blower Motor Wiring reversed?


maybe he used the fan on setting at the stat.

All 20 year old furnaces need checked annually. They are at the end of their expected life span.

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