blower won`t go off
#1
01-11-03, 03:31 AM
blower won`t go off
I have a old lennox furnace( natural gas) And the problem I`am having is that the blower motor won`t shut off. Even when I cut the unit off the blower still runs. Just replaced the old dayton motor and replace it with a new one. The old motor just gave out. The furnace works fine it just the new motor won`t cycle off. Can someone help please!!!!!!! By the way it`s and very old unit late 60`s to 70`s model. Thanks.
#2
01-11-03, 04:20 AM
A furnace of that vintage will use a fan or fan/limit control that's mounted on the wall in the burner section. Some of these cntrols have a little knob that you pull out which causes the fan to run full time. Check for that first. Did the same thing happen before you replaced the motor? If not, check your wiring. Do you have cooling? If yes, maybe the fan relay contacts are stuck closed. Let us know what you find.
#3
01-11-03, 04:51 AM
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On the Honeywell control bigjohn mentioned, if there is a white cylindrical button on the front, PULL IT OUT to put the fan in auto. Push it in for the fan to run constantly. What usually goes wrong with that control is it gets stiff and won't turn the fan off. Look at the old one beore you get the new one because there are different lengths to the sensing probe that extends into the furnace and you should get the one that matches your funace.
#4
01-11-03, 11:45 AM
No I did not have this problem before I changed the motor and it does not have cooling. What does the limit control look like? And where is it located? Is it in front of the furnace where I light the pilot light? Thanks. By the way I think this is the unit your talking about, For what I see it has two wires going to it one says load and the other says limit and it looks like a transformer and it says honeywell on it, is that what your talking about?
#5
01-11-03, 12:03 PM
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The fan and limit control incorporates the two into one control. It usually has 3 wires. One is power in and then one goes back to the burner and one goes to the fan. It should be an L4064 for the age of your furnace. It does not look like a transformer. It has a dial on it that you set the fan on and limit temps.
Keep looking.
Keep looking.
#6
01-11-03, 04:11 PM
fan and limit
The fan and limit will say load and limit. The honeywell fan and limit will have a cover on it that pops off about the size of a pack of butts. Did you say this started when only after you changed the motor? If so you screwed up the wiring somewhere along the line.
#9
01-11-03, 04:58 PM
Fan and limit??
Tag the wires BEFORE removal, pull out the fan and limit control, and take it with you to match up... it eliminates alot of questions..., note the three settings on it. The bottom setting is the temperature you want the fan to shut off at, The middle setting is the temperature to turn the fan on with, the final setting is the high limit setting to shut the unit down incase it should runaway. CAMSTAT and White Rogers also makes one. the Honeywells have about 6 different L4064 models with 5,8,& 11.5" probes.
#10
01-12-03, 03:24 PM
Okay here`s the deal, I found the paperwork on the old beast! It`s a lennox GF4-110 12/1957 model and it still work great except the fan won`t go off. I found the fan switch and limit, the fan switch has a degree scale on it like 120d 100d 80d and so on that`s all it has and the limit switch is right next to it and it has just wires running to it and it also has a jumper wire going to the fan switch. The fan and limit are boxes. Could it be the thermostat switch making the fan not to go off. Thanks.
#11
01-12-03, 03:41 PM
It shouldn't be the thermostat. Furnaces in those days didn't come prewired for cooling, so it probably doesn't have a fan relay. Shut off the power, remove one wire from the fan control and turn the power back on. If the fan motor is now off, replace the fan control. Be sure the new one has the same length probe as the old one. It's possible that the fan control is a timing device. You'll have to remove it from the firewall to find out. Ii might even be a "heat assisted" type. Be sure to go back with the right type. Didn't we have a guy couple weeks ago with an older Lennox and his was a heat assisted type like a HW L4064W? Any chance you can post some pics? We'd like to see an oldy for a change. Does it still have the original gas valve?
#12
01-12-03, 03:54 PM
It has a general controls a-100 series thermopilot relay original and a minneapolis-honeywell gas regulator on it(original) By the way where can I find the fan switch and I think it works by heat. And I will post some pics of it when I get it out.
#13
01-13-03, 02:51 AM
Your question- "where can i find the fan switch?" Do you mean where can you buy a replacement? Johnstone Supply, Graingers, maybe an appliance parts place locally. There are some website businesses selling heating/cooling parts. Try a search like furnace parts or similar. It sounded like you found the location of the fan switch on the furnace or is that the question?
#14
01-13-03, 05:56 PM
Fan and limit
When we say fan and limit, I think it would be far better, to refer to this, as a COMBINATION fan and limit control, so that you understand this is ONE piece. There are other manufacturers that make them seperate.
#16
10-19-12, 02:05 AM
Member
For a LOT of years! You still have the same furnace? In 2003 you said it was old. I would have it looked over by a professional before doing any work on the furnace.
#19
11-05-13, 01:35 PM
Heater fan blower won't turn off
On a Day & Night heater, the fan blower only turns off after unplugging power cord to the heater. The heater works fine, but blower continues to run after the heater shuts off when reaching temp set on thermostat. The fan is set on 'auto' or 'off' but doesn't shut off.
Previous posts say relay on circuit board may be stuck. How does the relay look? (see attached pics). Tapping relay may fix it ('unstick' position)?
thanks for any advice!
Previous posts say relay on circuit board may be stuck. How does the relay look? (see attached pics). Tapping relay may fix it ('unstick' position)?
thanks for any advice!
#20
11-05-13, 03:57 PM
Member
Disconnect the wire connected to G on the circuit board to rule out the thermostat and wiring. You can wrap the end in tape to prevent it from shorting anything out.
If the fan continues to run, the board is bad.
If the fan continues to run, the board is bad.
#22
11-06-13, 10:36 PM
Member
In your picture, there's a brown cable with 4+ conductors connected to screw terminals.
Disconnect the wire connected to the G terminal (it should have w/g/c/r/y), wrap the end in tape and turn the power back on.
If the fan still runs continuously the board is probably bad, unless someone wired it with an external relay to run all the time.
Disconnect the wire connected to the G terminal (it should have w/g/c/r/y), wrap the end in tape and turn the power back on.
If the fan still runs continuously the board is probably bad, unless someone wired it with an external relay to run all the time.
