Saturday Morning I walked to my hamshack, and was greeted by a smell something akin to exhaust gas along with a loud alarm going off as I opened the door.
A sealed-battery wall mounted Carbon Monoxide detector was going off and the room actually had a slight haze.
Obviously the direct vent wall mounted furnace was the cause.
So all the doors and windows were thrown open so I could investigate.
The old furnace unit was that old that it was discontinued with no parts available, AND its immediate replacement had also been discontinued as well!
It appears to be more than 30 years old, and I have reason to suspect that it might have been moved to the hamshack from another cottage type property when that other property was enlarged. So the unit may be well over 40 years old.
“Earned its keep” as they say.
The failure was hazardous but not enough CO came out to put the unit out of commission. So while I made arrangements I put huge warning signs on the door and retreated to the main house to start lining up temporary heat and a replacement.
Once I had borrowed several electric heaters from the heating & plumbing contractor I was working with, it was time to shut off the natural gas in the hamshack and throw the furnace breaker to off.
I really appreciated the solid and clear warning the sealed-battery wall mounted Carbon Monoxide detector gave. Made it crystal clear what I was dealing with from the moment I opened the door.
There is a lot of misconception about Carbon Monoxide detector placement. Some sources say put it high, some say put it low. Some web references claim CO is heavier than our usual air mixture. Few web resources consider that the CO at generation is warmer than the air, and that science indicates CO is fairly neutral compared to air.
So the manufacturers say keep it 6 inches away from corners, floors, ceilings and away from other situations that might prevent the CO detector from doing its job. Several insurance companies suggest 5 ft from the floor away from a room corner by 6-12 inches.
These all-in-one sealed units seem a decent idea. Not dependent on wall power or my battery replacement, and the important sensor gets changed out every ten years with the battery. I’ve order a few extra to put at the Island QTH and as a backup to the fancy wired sensor system in the main house.
While not exactly a main ham accessory, a good CO Detector in the hamshack is a plus.
BTW in replacing the wall furnace the natural suggestion by the contractor to put in a new high efficiency was rejected, as the latest and greatest units have some drawbacks. Without special preparation they shouldn’t be allowed to freeze. So if we decided to go away for the winter we’d be stuck leaving the heat on. Also the fancier units have a different risk of RFI issues compared to a straight forward traditional unit. The newest types are 14-16% more efficient than the new traditional type’s 80% rating, and the older failed unit is a bit less efficient than the replacement going in (about 6%). So the ability to shut the heat off without damaging the furnace and lower complexity with potential RFI exposure issues made sticking to the simple style an easy choice.