Pics are front & back. Happened down in Warrington today. Nothing I'm involved with. Someone local sent me the pics for my amusement. I'd refer you for the post-mortem, Mark.
Mike Brown of Inspect Express also has "Picture Drop" for Word. I've never tried it, but it looks like it might do what you need and much more. https://devwave.com/picturedrop
He's saying it needs an SS liner instead of stovepipe as a liner. I've found that every sweep now says that all flues need to be immediately relined or the chimney needs to be torn down and rebuilt - or the house will burn down. Some even say that if you don't do it, they'll report it to the fire marshal and your house will be condemned.
The recent responses are to a post from ShaunMcD, who does have a humidifier. The white residue can be made up of many things, but your issue is likely due to byproducts of combustion venting into your home and not outside.
It looks like the same format as Kenmore which is a letter followed by 7 or 8 digits. the 2 digits after the letter are the year. 00 = 2000 You can confirm with the date stamped inside the TP relief valve handle.
The white dust syndrome of humidifiers jumped into my head when reading these question but I guess the topic subconsciously kept me silent. It is quite likely the humidifier. I guess it could be salt from the softener, but is likely some other minerals in your water. Thoroughly clean the humidifier and and go get some distilled water. Let us know if this clears it up.
My dad (was a photographer) has been going to B&H Photo in Manhattan since the early 70s. Best customer service and nothing they don't have in stock. I buy everything from them online. If I can find it anywhere else for less, they'll match it (they've slit open a box to give me an "open box" discount). https://www.bhphotovideo.com/
Nope. IRC sez vent material "as specified by the manufacturer". All manufacturer's of cat IV furnaces will specifically exclude B-vent. Just did a building where 10 space heating units were just replaced with cat IV furnaces. I'm guessing the installer didn't want to change the B-vents through the roof. Click to Enlarge 48.66 KB Click to Enlarge 25.34 KB