3400A816 Electrical Issue
Posted: Sat May 22, 2010 7:49 pm
Hi Everyone,
I have found that Robert and the other admins here are excellent at providing guidance on some of these complicated issues. I am no novice at working on many different systems but these old units sometimes baffle me. I know I need to order a relay but need some help first.
This unit has been working flawlessly since Yall sold me the new sequencers back in 2008 except for last year the Fan Relay burnt out. I ordered a replacment and installed it, I had to put new spade terminals on one of the wires as it melted the insulation away. Well that worked great till last week when the tenant called saying there was a burning smell and the blower would not come on in AC mode. I purchased the schematics from the link on your page but it only gave me the schematics for the furnace unit, it didnt give me any schematics for the ac control box which is what I need to even attempt to verify the wiring and all.
Upon inspection I found that the Fan Control relay had burnt up (pic will be bleow) It burnt up the wire and end on pin 2, which if I am not mistaken is the load wire that feeds to the start cap and on to the blower motor. Well after replacing the relay and testing the unit for a short time (about 10 minutes) It seemed everything was ok.
After 2 days passed the tenant called again saying that the same thing had happened again.
I inspected the unit and found that the relay is totally fried this time a bit worse, it appears that something is overloading the relay causing excessive draw on this relay thus causing it to cook, and boy do I mean cook. This time it burnt mutiple wires going to the relay. I have cut out all of the burnt up wiring and started rewiring the damaged sections but I have a feeling that something is causing this to keep happening? I do know that when it happened the 1st time (last week) that there was a tremendous amount of heat comming from the unit when I pulled the service door off of the unit. I could not pinpoint the source I felt it may have been the blower motor as that is the only thing fed by the relay.
I didnt suspect the start capacitor as I didnt think the blower would even come on if the capacitor was open or shorted??
I would apperciate a second opinion on this issue. I only want to place one order for the needed parts so I can get this unit back up as quick as possibile.
Thanks again for all assistance for now and in the past.. It is always apperciated..
Sincerely
Roger
Pics Below
I have found that Robert and the other admins here are excellent at providing guidance on some of these complicated issues. I am no novice at working on many different systems but these old units sometimes baffle me. I know I need to order a relay but need some help first.
This unit has been working flawlessly since Yall sold me the new sequencers back in 2008 except for last year the Fan Relay burnt out. I ordered a replacment and installed it, I had to put new spade terminals on one of the wires as it melted the insulation away. Well that worked great till last week when the tenant called saying there was a burning smell and the blower would not come on in AC mode. I purchased the schematics from the link on your page but it only gave me the schematics for the furnace unit, it didnt give me any schematics for the ac control box which is what I need to even attempt to verify the wiring and all.
Upon inspection I found that the Fan Control relay had burnt up (pic will be bleow) It burnt up the wire and end on pin 2, which if I am not mistaken is the load wire that feeds to the start cap and on to the blower motor. Well after replacing the relay and testing the unit for a short time (about 10 minutes) It seemed everything was ok.
After 2 days passed the tenant called again saying that the same thing had happened again.
I inspected the unit and found that the relay is totally fried this time a bit worse, it appears that something is overloading the relay causing excessive draw on this relay thus causing it to cook, and boy do I mean cook. This time it burnt mutiple wires going to the relay. I have cut out all of the burnt up wiring and started rewiring the damaged sections but I have a feeling that something is causing this to keep happening? I do know that when it happened the 1st time (last week) that there was a tremendous amount of heat comming from the unit when I pulled the service door off of the unit. I could not pinpoint the source I felt it may have been the blower motor as that is the only thing fed by the relay.
I didnt suspect the start capacitor as I didnt think the blower would even come on if the capacitor was open or shorted??
I would apperciate a second opinion on this issue. I only want to place one order for the needed parts so I can get this unit back up as quick as possibile.
Thanks again for all assistance for now and in the past.. It is always apperciated..
Sincerely
Roger
Pics Below