Olsen oil furnace fan continuously blowing.


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Old 11-13-17, 06:31 AM
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Olsen oil furnace fan continuously blowing.

Hello, I have an Olsen furnace and the fan is continuously blowing. Our furnace tech is stumped. We have replaced the high limit switch, thermostat on wall, and the circuit board for the unit. Still no luck getting the fan to shut off. When we have it running, it seems the temperature doesn't get up to the thermostat temperature setting and shuts down before reaching that temperature. Once the burner shuts down, the fan keeps running nonstop but heat doesn't kick back on. Any ideas what could cause this?
 
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Old 11-13-17, 05:32 PM
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When did the problem start? Something changed somewhere along the line.
 
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Old 11-13-17, 07:31 PM
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Welcome to the forums.

It sounds like you need to find a new tech. That should not be that hard of a problem to find.

In order for me to help you I need a model number for that furnace. It may be inside on the side wall behind the access covers. I may not be able to get any info online about that unit. When you have the covers off... see if you can find a schematic or wiring diagram. I can work off of that.

Take a closeup picture and post it here. How-to-insert-pictures
 
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Old 11-20-17, 07:37 AM
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We had a power outage a few weeks ago. I assume that is when the issue started.
 
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Old 11-20-17, 07:45 AM
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Pics of circuit board replaced and model numbers.

The manual for the furnace you can pull up online no problem. Ill see if I can share the link. https://www.google.com/url?sa=t&sour...nzaTOwKTDPSXpi
 
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Old 11-20-17, 10:02 AM
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That furnace uses a blower timer board.

Three things can keep the blower running...
1) defective timer board
2) improper power on G terminal. Possible thermostat problem.
3) furnace is overheating and opening a limit control. That will keep the fan running without the burner.

You mentioned the furnace is overheating and not reaching set temperature. That can be cause by over firing, fan speed too low, clogged air filter, too many closed registers, blocked air returns.
 
 

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