I found this picture on the net of the little red push button:
So now that I know what to look for, I can see that same button in my limit switch, only mine is black:
Now the only safety switch I haven't found is the VSSS Vent safety shutoff switch.
After googling for a while, I think the reason I can't see the VSSS is because it's *inside* the plenum!
I think it's attached to the brown board, like this from the net:
So, the VSSS would then be on the other side of *this* brown board:
Is that correct?
When that trips, it's in series with all the other safeties and will cut the 24vac control voltage to the furnace. If it isn't an automatic reset, you have to find the little buttons and push them in to reset the control circuit. Like a circuit breaker, it tripped for a reason so you need to investigate the cause. This is where experience comes into play. Perhaps a friendly service tech will show you what's wrong and answer questions about it. I had a little old lady crawl under her house with me so I could show her what was wrong with her furnace and what needed to be done to repair it. ^_^
TDD
The small cylindrical thing with a red tip on one of the wires is a "one shot" thermal fuse and if temps get too high it will pop. It's in series with all the other safeties and will kill the control voltage. ^_^
TDD
Now, but when the unit was installed? I know of two units that are operated that way.
I am not saying that it is right, just that is how they were installed.
That 'stat is old work horse using wet mercury bulb switch. It is tilting up/down by temp. sensitive bimetal coil. Just leave it at about
75 deg during trouble shooting(to make it call for heat) Leave it alone and adjust it when problem is fixed.Don't worry about lock up timer it only starts when safety issue arises like over heating triggering over heat limit sensor. This is kind of thermostat for fixed temp sensing. There are few in there for different functions/purposes. If you want to reset the lock out timer just power cycle the furnace,(resetting control board) Hope it is not cold there. It is -18C up here tonight.
You in Silicon valley? In San Jose area? There I have a good friend of mine who runs company called K.Y. systems. His back is EE like me. He may may not help you if you call him and mention my name, Tony(VE6CGX). His name is Young Kim. He goes out of country often on business.
Hi, That is located inside the flue. You took a pic. of it. Sqare bakelite lo0king thing with two wires mounted on the flue. The sensor is inserted into flue to detect vent gas temp. This is one of couple safety thing when triggered furnace will shut down pronto and lockout timer starts. You can't see the lockout timer counting pulse w/o 'scope.
How are you heating, now, with the furnace broken?
Normal is based on the size of the house, climate, windows, insullation, occupancy, how often the doors are opened, trees, sunshine, price of fuel, and a couple other things. Normal isn't the same for everyone.
Yep, connect red to red, to call for heating. Sigh. (shakes head)
Replace wife. Problem solved.
Get the brand new, high efficiency wife. Works in the cold, uses 30% less power, leaves toilet seat up, never runs out of milk or sugar, and is EPA compliant for ozone emissions.
Mea culpa. That was (just) a typo. I had corrected it a few minutes after I had posted (but you responded to the original). Sorry. That was my mistake.
California weather is so moderate that you can live the entire year sans hear or air conditioning ...
It's only around 32 degrees for a very short while, just a few hours in the early morning; and then it's back up to 50 or 60 during the day.
We don't even drain the garden hoses ...
Very well, my son. Please recite ten Book of Mormons, twenty Angel Moronis, and go and sin no more.
Hope you get your heat running, safely, soon.
I'd live there. Except for the politics.
More likely there will be a pile of disasembled parts all over the place. He seems to prefer that to focusing on the obvious. So, the furnace doesn't fire up. Who starts by taking apart the tstat, asking 100 questions about how to debug it, without going to look at the furnace and seeing that the blower door is off, that he took off a few months ago? Good grief.
I have to give him credit for the longest threads, the most pics, etc. IMO, he should just call a tech.
called K.Y. systems. His back is EE like me.
*cough* Sorry...K.Y. and Easy Entry? :-)
Best add "makes a sandwich" and brings a "beer".
He definitely needs to slow down a bit and wait for a few more TSR tips to show up.
Trouble shooting starts with the basics, not what one suspects unless the symptoms are a known, recurring event. By setting up the system for a normal start sequence, and waiting the appropriate amount of time, all of the issues with the T-stat would not have been.
If the system was reset and things were started over again I would wager that the unit would work again. This time, do the test with the cover in place. Check for normal operation, first, then find out why things are not working. Find the path of electricity (hence, the logic of the circuit), and follow it until the path stops. Just bumping the interlock would not cause any of the other safeties to engage, and would restart the start up sequence.
Just as with physics, observation with repeatable results is necessary to figure out what is going wrong. As for his AC, I wonder if there is a blown fuse out in the fusible disconnect outside.
In one of the Scott Adams "Dilbert" books, he tells of a company that called a copier repairman. The engineers had dissembled (dismembered) the machine, and written notebooks of theories on why it wasn't working. The problem was someone put toner in the imager container. Normally a half hour diagnosis and fix. To reassemble the copier and reset all the timing gears took several days.
A *lot* of things get fixed, simply by throwing parts at the problem. Nothing wrong with that. Sometimes the person throwing the parts actually knows what they're doing; sometimes not.
Take the oft-cited case of vibration when braking? Must be "warp", right? The rotors must be warped like a potato chip. Solution? Replace (or turn) the rotors. Right? Everyone knows this, right?
When *I* had vibration while braking, I tried to measure this so-called "warp". You can't measure it on the car (that would be runout), so, I measured it off the car. Hmmmm.... there was no warp. Huh?
Turns out, for normal people (not racing braking systems), warp just doesn't really happen. While a ton of suspension components can cause vibration at various speeds, the classic brake-related vibration at speed is caused, usually, by disk thickness variation caused, most often, by braking deposits, building up over time.
The solution, once you *understand* that, is to change your braking habits (so as not to build up those deposits).
Yet, if you don't bother to understand what causes the vibration, and you simply replace the rotors, you'll solve the problem quickly, but it will eventually return. And, most importantly, you'll be solving the problem without understanding the cause, which means you'll think your entire life that your rotors are warping. You might even vainly try to buy beefier rotors in the hope that they won't "warp" as much. Which means you'll be solving the problem with the right solution but for the wrong reasons.
Anyway, same thing with just jumping the red wire to the white wire. If I didn't understand first what the red wire was supposed to do, and what voltage it was supposed to have, and what effect it was supposed to have on the furnace, etc., then I would be remiss.
Of course, had I just disassembled everything and reassembled it, in this case, I would have solved the problem sooner, as now it's all working after I disconnected *every* wire, and reconnected them after cleaning them. I also tapped ever solenoid and relay I could find and blew the whole thing out with compressed air.
At the moment, it's working! Thanks to everyone! I very much appreciate the help.
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