Carbon Monoxide from Furnace

Cracked combustion chamber........do not use furnace until you replace chamber.

The problem with combustion/exhaust fan caused the chamber to overheat and crack due to insufficient air flow.

You folks are very generous with your comments and rich in experience. I have passed everything on to the technician and I will repay your courtesy by sending back the results (hopefully in a couple of days).
Harold

A heat exchanger is checked by putting a smoke bomb into the burner area. You then look into the plenum and if any smoke is seen it is scrap metal.

Handbasket wrote:
On a home furnace, I'd suspect a cracked heat exchanger. Not totally sure the same logic applies to an RV, but I suspect it does.

Unlike Jim.. I'm sure, well half sure.. ONE of the things that can cause this is a cracked heat exchanger.

Here are two (or 3) more. which you might find interesting.

Parked in Quartsite in 2006 the furnace side of my RV was "Into the wind" it got cold at night.. I very strongly suspect the "Breeze" (you really do NOT want to know the MPH) was blowing the exhaust back into the house.

Also the neighbor's generator

next year I parked on the other side of the group so the wind blew it AWAY from me.

Also my own generator operated WITHOUT a Gen-Turi, will fire off the CO alarm in just about 2 hours.. WITH the Gen-turi.. I've done a couple 25 hour tests.


So the solution may be as simple as turning the RV 180 Degrees so the wind hits the other side.

One more thing.. I have not seen this but I am not an RV service technician.. I just work on my own and occasionally help a friend.

The compartment is not all that well sealed.. IF there is an alignment issue with the exhaust and a cover.. Might be a factor..

Co is produced as a by product of incomplete combustion. After making sure that you have the correct flame the next issue is exhaust. Something probably was not hooked up and was allowing exhaust gas back into the camper. CO detector's going off in two ways. A rapid build up and a gradual build up over time. I always recommend a model with a LED readout. You can see a problem developing way before it becomes dangerous. Don't forget to check the water heater for issues. Just be careful because I've seen a lot of furnaces in houses being replaced do to "CO" issues when it turns out it was a blocked exhaust pipe.

Well, now, there ARE combination gas/CO detectors for both propane/natural gas and carbon monoxide. I have just such a unit in my workshop; bought it at Lowes.

I don't know that they use them on RVs, but the technology is definitely in existence.

I'm sure the OP knows about the toxicity and lack of smell of CO, having suffered a three week head ache. I trust he's also aware of how lucky he is to still be on this side of the grass.

CO is differant from Propane and I doubt that the propane detector can detect CO Rather than shutting down the furnace and gas they ( the firemen) should have used their CO detector to pin point the problem. I would bet that you have a broken heat exchanger in the furnace. AND any Rv furnace I have seen uses one motor and has a double ended shaft to power the blades. One for the heat and the other for exhust. Did he really put in a new motor? I would look hard at the heat exchanger. Don't forget CO is orderless so you can't smell it. And CO is lighter than air so you want a detector near the ceiling. Propane at the floor

Could be cracked heat exchanger, blockage in exhaust, or a problem with fan motor housing. My other question is that most RV furnaces use only one motor to run blower and air exhaust for the combustion chamber. If the motor was bad both sides would have been effective.

I wonder how hard it would be to pull the furnace and have it tested on a bench. That would factor out a lot of issues. Some RVs, one can just lift up a dinette seat and have full access to the furnace. Others take some work to get at them.

Barring a window or other hole open that would suck in air from near the furnace exhaust port on the outside, it either is a leak in the intake/exhaust line, or a cracked heat exchanger.

On a home furnace, I'd suspect a cracked heat exchanger. Not totally sure the same logic applies to an RV, but I suspect it does.

Jim, "Why do I wear loud socks? To keep my feet awake!"