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View Full Version : Blower motor relay or limit switch?


brian1
Jan 7, 2012, 11:46 AM
I have a problem with my blower motor staying on or blowing continuiously, even when cold and as well when my thermastat is turned off. If I tap my limit switch the fan will shut off. I tested my relay and there was no continuity at that time. However when I pressed the reset several times and tested the relay again there was continuity. The relay is testing and reading continuity now but the blower fan still stays on. I have tested the limit switch (it has two separate units by the way). I am assuming one controls the oil burner cycle and the other controls the fan cycle. They both tested OK. Interestingly enough when I try to switch from manual to auto the fan stays on as well. The thermostat tested OK as well. Any suggestions or thoughts.

mygirlsdad77
Jan 7, 2012, 01:05 PM
Well, if the fan turns off when you tap on the limit switch, I would think that would be a good item to replace first.

brian1
Jan 7, 2012, 03:04 PM
I want to thank "mygirlsdad" for confirming the answer that I suspected. However I am curious as to weather the relay is weak as well. Should I replace that too? Also while we are discussing the limit switch. Could you suggest where I might locate a limit switch that was made by honeywell originally. The model number is L4068f1003 3 BD (OR A SUSTITUTE that would work). This is related to my earlier post for a limit switch off a Beach model 600 oil fired furnace. Any help would be greatly appreciated. I have been searching locally for days and on the internet with no luck. Thank you in advance.

mygirlsdad77
Jan 8, 2012, 01:00 PM
Sorry, can't help with that one. I would take the limit to a local heating company and see if they can find a universal (or even exact) replacement. Model and serial of the furnace itself would help them.

Just out of curiosity, can you post some pictures of your limit and relay? I really don't work on oil burners, just don't have any in my area, but many of these components are somewhat universal.

brian1
Jan 8, 2012, 02:38 PM
Thank you again for your help. Here are the pictures of both the limit switch and the relay.

mygirlsdad77
Jan 8, 2012, 03:03 PM
That's old school stuff. However, if you can find a heating company that has been around for a while, they should be able to hook you up with the correct universal replacement parts. I still think your limit (which looks like a fan control, and high limit all in one from the first pic) is the issue. You may be able to replace that with a universal honeywell fan/limit control, but I wouldn't know for sure without seeing the system first hand, right? Do you have a good reputable heating company in your area? If so, I got to say, its time to call them in. Or at least see if they can help you get a replacement part. Do know, however, that if you call them in, they may suggest replacing the complete furnace. I know, that sucks, but in this world we live in, it pretty much has come to a throw away world. If we can't fix it, you need a new one mentality. May be hard to find a pro that will have the skills to work on the old stuff (dying breed we are, for sure). I wish you the best of liuck on this, and please let me know how things go.

PS. I wish I could say different, but I don't really think your going to get any great easy fixes online. This ia an older system that would really have to be looked at first hand to see what a person is dealing with. The net will drag you in so many different directions on this type of thing, it will make you dizzy and sick (as Im sure you have found). Don't get me wrong, the web is a great thing, but some things still require hands on expertise. Take care.

brian1
Jan 8, 2012, 06:20 PM
Thanks for all your help and I will let you know how things turn out. I may just bite the bullet and purchase a new unit. Really appreciate your help mygirlsdad. All the best!