"Open rollout switch circuit" error message in furnace.

"Open rollout switch circuit" error message in furnace.
A friend called me and said his gas furnace keeps shutting off. It's fairly new and a high effencincy type, which vents out thru PVC. It has a digital readout which says "Open rollout switch circuit". I googled that, and found a simple drawing which shows it as a sort of sensor, and found a picture of one. Not much more.
I emailed him the pictures and told him to shut off the power and set his meter to OHMS and check that switch. He said there are two of them and they are both turned to the ON or CLOSED position (Not open).
The outside temperature is well below zero, and he has kids, so I told him he better just call a furnace repair company. If it was an older furnace I could probably fix it, (assuming I could get parts), but I dont know anything about these "computerized" furnaces.
He called a furnace company, the guy is swamped with calls, but said he will come as soon as he can, but that could be several hours. The guy told him to use space heaters till he gets there. Even if I thought I could help, I doubt my truck will start in this cold, so it dont make any sense to try, knowing nothing about these kind of furnaces.
All I know is that it's a Lennox and it's giving that error code.
While I'm sure the furnace repair guy will get there before I even get a reply on here, I thought I'd post this to see if any of you know anything about it... I always like to learn new home repair stuff.
What's the purpose of these switches and what could be wrong?
I did tell the guy to make sure his intake and output pipes were not clogged outdoors. He said they are fine! He also tried another thermostat, since he had saved the old standard one when he replaced it with a programmable one last fall. That did not change anything, so we know the t-stat is not the cause.
Anyone?
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On 1/10/2016 11:47 PM, snipped-for-privacy@alt.home.repair wrote:

The switches verify the presence of flame where it SHOULD be and the absence of flame where it SHOULDN'T be!
You (he) could have a blocked heat exchanger which is preventing the flames from flowing up through it and, instead, backing up into the blower compartment (*outside* the heat exchanger). Likewise, a blocked flue or something blocking the combustion relief (not enough air to support combustion).
Or, low gas pressure causing the flames not to jet into the heat exchanger fully (doubtful).
There are usually diagnostic LED's on the control board (*in* the furnace; usually in the blower compartment, NOT the burner compartment) that will give you some detail as to what is happening.
The switches can usually be reset, manually. But, this is A Bad Idea and really should only be done by a qualified technician - just to run the furnace long enough to understand why it/they are tripping. They function similar to a fuse: they should NEVER trip -- doing so means something is likely very wrong.
You (he) may be able to get the furnace to run by reseting them, but run the risk of CO poisoning, fire, etc. as the reason for their initial trip probably hasn;t been fixed!

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On 1/11/2016 3:26 AM, Don Y wrote:

Sometimes it's wind across or down the chimney that causes the problem. There is a good chance it's a rare thing, and the furnace is okay, now. In western NYS, it was very extremely windy last night.
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Christopher A. Young
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On 1/11/2016 1:47 AM, snipped-for-privacy@alt.home.repair wrote:

fail to go up the chimney. Very often when it is windy, the wind pushes "down" the chimney, and prevents the flue gas from going up and out.
If the wind has changed, it may be fine to reset the switch (if it has manual reset button) and he's good to go. If it trips again, might be a birds nest or some other thing blocking the chimney.
I'd not want to reset it more than once, there is a real risk of killing your family with carbon monoxide.
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Christopher A. Young
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On Mon, 11 Jan 2016 07:26:12 -0500, Stormin Mormon

condensing furnace with pvc exhaust going throgh the wall.
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On 1/11/2016 3:06 PM, snipped-for-privacy@snyder.on.ca wrote:

I'm sorry that you can't figure out what part of the system behaves like a chimney.
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Christopher A. Young
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conditions. I have found that the intake fan creates such suction on the intake pipe that it can cause the temperature of the intake air to drop below the outside air, and when the wind blows the "fog" from the exhaust discharge across the intake line, it sucks some of the "fog" into the intake pipe and freezes it just inside the intake pipe. This builds up over time when the outside air is really cold and slowly blocks the intake pipe until the appliance cannot get enough air. At this point the switches detect a vacuum in the intake line and shut the heater off.
The moral of this story is go outside and check the intake and exhaust lines to be sure that there is no blockage such as snow or ice over or inside the lines (an animal may have tried to get in and got stuck or killed by the exhaust fumes) and clear out anything you find. Put some mesh over both lines to keep animals out.
Also look up the make, model and type of furnace and then go on line to get all the manuals from the manufacturer. The installer may have not left anything hoping for service calls. There is often a trouble-shooting repair manual that is available if you look.
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snipped-for-privacy@alt.home.repair posted for all of us...

If it's "fairly new" why not have the installing company fix it? It should have been serviced prior to the heating system then this is avoided. Solving this is very hard by third person. Measuring the switches does not really tell one what's wrong. Have him man up and get some heat in there.
--
Tekkie

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On 1/11/2016 1:47 AM, snipped-for-privacy@alt.home.repair wrote:

OP. Perhaps the furnace burned down and killed them all with monoxide?
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Christopher A. Young
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