What happens electrically when the oil furnace doesn't ignite?

[mm]

I know what happens electrically with my current old oil furnace when the oil doesn't ignite. A relay is tripped that has to be reset mechanically with a red button.

But someday soon I may need a new furnace and I don't know how they work.

Here is the reason: I'm getting a new burglar alarm (mine went up in smoke, literally) and my friend told me they had a built-in temp sensor, to notify them if the house temp got too low.

It turns out this model requires an add-on switch, and while trying to decide where to put it and how to wire it, it occurred to me: Why wait until the house is getting too cold. Then if I'm away, my friends only have a day or two to get there and fix the furnace and warm the place up. Why not also notify the monitoring company there is a problem when the furnace first tries to ignite and can't (no fuel, nozzle clogged, furnace broken, etc.)

My current furnace has a mechanical relay, a latching relay I presume????

and if it is not double pole or double throw, I could buy a latching relay that is, and use it instead and connect the unused pole to notify the alarm that the furnace needs resetting. I would give that its own zone, so that I would notice it even when I was home, when setting the alarm.

But I'm guessing everything is transistorized in a new furnace I buy. I don't have trouble working with IC's and circuit boards, but that doesn't mean there will be a place to connect. Is there any way to do the same thing with the new furnace? Is there a brand of furnace that would make this easier than other brands?

[RBM]

There may be depending upon the burner, however the problem with your current thinking is that the burner primary control,(the box with the reset) doesn't necessarily have power to it at all times. Once other parts of the control system send power to the primary, its internal controls assure that the burner makes fire, and if not, locks it out. Without building a complicated contraption, the easiest solution would be a temperature sensing device and a phone dialer.

[trader4]

While I'm sure you can figure out a way to do this, I doubt it's worth all the trouble, such as trying to decypher and wire into the electronicc ontrols of a brand new furnace. As noted, the burglar alarm has the ability to monitor temp. As long as the temp to set off the alarm can be set to just below the temp you keep the house at, say

3 to 5 degrees, I don;t see where the furnace alarm is going to give much additional benefit. If the alarm doesn't allow a temp you like, but has external inputs, I'd just hook up a termostat to it.

I see 2 scenarios. One, it's winter and 10 degrees outside and the furnace fails to start. The only thing you gain with the furnace alarm is the time it takes for the house to drop 3 degrees, which might be an hour or two at most, which hardly seems worth the trouble, as you still have quite a bit of time before anything is going to freeze. Or other scenario is it's Fall and 40 outside, in which case it may take 6 hours to drop and trigger the alarm. But, in that case, you have days to fix the furnace.

[RBM]

While gas burners tend to have more sophisticated controls than oil burners and would probably be easier to tie and alarm to the lockout function, you'd still be leaving yourself vulnerable to failures of other parts of the system, like thermostat failure or wiring failure or power failure. Ultimately temperature is what you're concerned with, and the simplest thing to tie an alarm to

[mm]

I should have said that I plan to go away next winter, for maybe 2 to

4 months, for work, and plan to keep the house at one of the temperatures we've talked about here. 50? 48? And the temp was to be that high on the theory that it might be colder by some of the pipes than it is at the thermostat. 45? 43?

And I'll be depending on a friend yet to be chosen to come, figure out what is wrong, and fix it. Whichever friend I enlist, I'm afraid he'll do it but will take too long. Maybe I should drain the pipes, and put antifreeze in the toilets and drains, but I figure the furnace lockout notification will be useful even on other trips of a week or so.

RBM is right about the potential problems in the other parts of the heating system, but in all but one case, it was the red button that needed pushing, sometimes for no special reason that I could find. I also once ordered fuel just before a trip, and gave them my credit card number and the fuel never came. That time, I didn't run out until

2 weeks after I got back.

That one case was a 3-day power failure, the only one more in 23 years that lasted more than 28 hours. If the house temp hadn't been 68 to start, maybe it would have gotten freezing cold inside. But the alarm comes with built-in power failure notification.

[mm]

Are you talking about the new electronic furnaces, or my barely electronic one? (Currently I have 15 resistors, 10 little capacitors, a few transistors, and that relay with the red button in a little grey box a little taller than a box of kitchen matches.)

BTW, I am also going to have the temp sensor and, because my friend owns the burglar alarm company, the whole digital communicator bit, with monitoring. And the alarm comes with built-in power failure notification. But if I can get myself another day or two, it doesn't have to be the easiest solution. After all this would be a fun project.