Problem w/Circuit Breaker on Door Panel of Forced Air System

[cmsan]

Hello all. I broke the forced air system, while simply removing the front panel to replace the air filter! I can see exactly where the problem is occurring though and it's right on the silly front panel frame!

The problem is a circuit breaker (says Carlingswitch 0534 10A) that is mounted to the inside front panel frame (an area where the removed panel screws *onto*). This is an odd breaker, though I'm no expert on them, but looks weird b/c has grease that's been I'd gather manually applied, and the fuse part is exposed and the first I ever noticed this thing, it has a "tongue" of metal which does *not* look like it broke off due to normal circuit breaker tripping, no breakage marks but just looks like it fell out of where it's supposed to be. If I take this tongue of metal and push w/plastic so it touches two contacts I can see, the system comes back on. But there's nothing I can figure out to keep it touching the contacts and it jiggles off with any slight jarring.

Before this problem occurred I banged on the front panel a bit with a hammer to get it to seat properly and shift down a bit and I'm thinking this jarred this little tongue out of whatever proper position it was in.

Weird question and a weird circuit breaker. I'd prefer not to spend alot on an electrician just to deal with this simple thing.

Anyone help? If noone wants to help can anyone explain the purpose of an odd circuit breaker mounted to the door frame like this?

[DerbyDad03]

Sounds like a safety interlock switch that shuts the system down when the panel is removed. It's for "user protection" so you don't get your tie or shirt sucked into the blower or wrapped around the pulley as you lean in to change the filter.

If that is indeed what it is, I'll leave to you to decide if you should bypass it so it never turns the system off, and then label the panel in a clear and permanent manner to inform all others that the safety switch has been bypassed and that danger lurks behind the panel.

The worst case is when the blower is off, you reach in and the blower turns on.

[Mikepier]

Thats exactly what it is ,an interlock. My Trane furnace has the same thing. Like DerbyDad says, mark the panel cautioning other users that it has been jumped out. But you have to remember to shut it off through another switch whenever you have to service it or change the filter.

[DerbyDad03]

nd the

e quoted text -

We used to jump out the interlocks on room-sized transmitters that normally ran at 15KV.

Sometimes they would arc to the chassis and you couldn't see the problem area with the panels on. We'd remove the panels, jump out the interlocks, turn off the lights in the transmitter room and run the unit up to 15KV, then 20KV, then 25KV. When it finally arced, trust me, you'd know where the problem was.

First we'd clean our pants, then we'd fix the problem.

[metspitzer]

That is the way I fix things. I have a large assortment of hammers. :)

[cmsan]

It just occurred to me, could this be a spring-loaded fuse that it's intended to trip when the panel is removed? That would make sense to ensure that the system does not function when the panel is off I guess. Yet I see no sign of a spring-loaded mechanism in this thing that could be pushed in and out, etc. But like I said this is a weird breaker with lubricant applied, the workings exposed and facing outward, and facing outward right behind one of hte panel edge surfaces. Hence this spring-loaded idea or somethign similar would make sense....

[DerbyDad03]

re: It just occurred to me, could this be a spring-loaded fuse that it's intended to trip when the panel is removed?

Did it occur to you to read the responses before you posted?

[Mikepier]

First of all , its not a fuse, its a switch. And yes, it is spring loaded. When you put the panel on, it pushes the switch in which completes the circuit to the furnace. Take the panel off and the switch pops out thus de-energizing the circuit.

[cmsan]

OK! Another update, problem more or less solved - after my previous post I thought I must have nailed the issue and I guessed that something may have fallen off and that's why I was looking at lubricated parts etc. So I looked around under where this piece sat and sure enough instantly found a piece on the floor that exactly fit my guess above. Turns out I broke off the front of a push-button thing that is a safety thing to trip a circuit when the panel is removed. I hadn't remembered this thing being there. The push-button portion had broken off and fallen on the floor, hence the lubricated parts I referred to were the internals. I got this plastic piece back on the front and there is in fact a spring on that button as I had speculated may be the mechanism and that is pushed by the panel when the panel is attached and hence now there is something to "push" that metal tongue I referred to in, so system is back running.

Anyone know where I can get a new switch like this if I need it in the future? It would have to fit quite precisely it looks to me? Any electric supply specialty place should have it?

[The Daring Dufas]

ext ->>

Did you keep your Jesus stick close by?

*snicker*

TDD

[DerbyDad03]

If by Jesus stick, you mean a Dead Man stick, yes we did.

Long wooden stick with a metal rod bent into a hook at the end and a braided grounded strap.

Their main purpose was to short the large oil-filled caps to ground before taking the bus bars off, but supposedly they worked for pulling bodies out of equipment if need be.

We also used them for training purposes to show the newbies why they should never go into the transmitter building without a transmitter tech. Take an oil-filled 15 farad cap into the mess hall, hi-pot it up to 5 or 10 KV, turn off the lights and short it out with the Dead Man stick. Even the most seasoned lifer understood the dangers of the transmitter building after that.

One time we got over zealous with the hi-pot and went too far. When my buddy shorted out the cap, the rod that was threaded about 4" into the wooden handle blew out, reached the end of the grounding strap, sprung back and hit him in the knee. He was limping for a week!

[Mikepier]

Ok, stop what you are doing, and slowly back away from the furnace.

[The Daring Dufas]

We civilian broadcast engineers referred to them as Jesus sticks. I imagine our Muslim counterparts call them Allah sticks. When I worked at the Kwajalein missile range 20 years ago, there was a huge building that to my understanding was the prototype for the phased array radar stations that watched our skies during The Cold War. The power supplies for the huge things looked like something out of an atom smasher. The guys called them Frankenstein rooms. There were Jesus sticks hanging around everywhere. Those old installations were fascinating.

TDD

[Lp1331 1p1331]

FWIW, the switch is not there to prevent anyone from sticking their hands into the blower or getting shocked. It is there to insure that the blower door is put on properly so that the blower does not cause a negative pressure in the furnace room or closet and cause deadly fumes to be sucked into the system. That is the most common cause of CO poisoning with central heat, at least around here. Preventing injuries from the blower itself or live electrical connnections is a fringe beneft of the switch. If it was the main concern, they would have them on air handlers and electric furnaces also, which they do not-- at least on any I ever saw. Larry

[Mark]

Take the switch out, take it to the parts store and drop the 25 bucks to replace it. Why defeat a safety device needlessly when it could cost you or one of your family members their life?

[metspitzer]

Search the Internet for the part number. You might get someone to bring it to your house.

[cmsan]

You know I did, or thought I did. This is my next quandary I guess. I'm using Windows Vista Mail and I do the command Tools:Synchronize:Get New Messages as my way of getting new messages. Using that, I didn't see any of these messages except for this one you wrote above.

After seeing these other messages on google groups, I downloaded the entire newsgroup into the Mail program,which was over 100k messages and still in this thread didn't see anything but your message.

But now I deleted the database files on my machine and the backup files it kept as well and then reloaded this newsgroup and now I'm seeing all the messages!

Perhaps it's just my news provider had it's head up its ass for a bit there but I'm amazed I'm seeing the messages all of a sudden when I delete the database. There was a gap of time in between.

Unfortunately the news provider doesn't have a way to browse their server via web as a definitive way to see how their server sees the newsgroup...

[cmsan]

I'm still here. Thankfully I wasn't contemplating the essence of the tongue-shaped piece of metal while hovering over the blower with a necktie on or anything. ;)

[cmsan]

Makes sense. Quite interesting. Not such a silly thing after all I guess. Can you explain how this thing works a little more with the "negative pressure" business? I guess what you're saying is that the air should be drawn from the cold-air intake and not from the furnace room surrounding area and this thing is built to ensure that? That seems a bit surprising since it's not like vapor-lock sealed or anything of course, and I had always assumed a certain amount of air would be sucked in from the surroundings but you're saying no that absolutely should not happen. So very interesting... But isn't it still a problem if there's CO in the surrounding air of the furnace anyway? I mean, that's part of the house too... How does CO escape from the natural gas and blower system anyway?

[cmsan]

I feel a need for a rubber hammer - always seemed like the ultimate in hammerless hammering to me. :)