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Missing Link


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I ran into this somewhat unfamilliar item a while back.

Has anybody seen this type of furnace in their travels?

Ooops, I'll put the photos on a diet next time, sorry. first time [:-banghead]

The furnace is called

Mortemp Chimney Furnace Serial Number: 511 –

Natural Gas-BTU rating 95K

TD = 55F

This furnace appears to have been built at the same time the brick chimney was built, hence the name.

The black control on top right is a fan limit switch and interlocked with the blue box in the second photo.

The fan is in a cabinet, located in the attic and unsulated with SM blue board. The return ductwork was buried in the rockwool/vermiculite combo insulation.

Download Attachment: icon_photo.gif MortempChimneyFurn1_S.jpg

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Hi Robert,

I had one about three years ago in a Seattle home. I don't remember whether it was the same brand, but the concept was the same - the chimney was the furnace and the rest of the controls were fitted to the chimney like they'd been on a furnace. The one I saw had been taken out of service and the house converted to electric heat. As I recall, the chimney had been built with an inner and outer jacket so that air could circulate around the outside of the firebox and rise and fall up through octopus-style ducts and grates throughout the house.

I hope you were wearing a good respirator poking around that vermiculite insulation. We don't want you to come down sick 25 to 30 years from now with mesothelioma.



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I call this the missing link because the way I understand it we had gravity (octopus) furnaces then we moved into the central concept with a fan etc.

This furnace is 1954 so it kind of falls in between and with a serial no. of 511 I'd suspect there is a very limited number of them.

This is the first for me and I'll tell you I was just like a kid at the zoo. The home was built by a gentleman who died recently at the age of 95 and was in the construction industry. The home was 'pristine' 54 condition. I looked at the woodwork for marks and found very few. The door and windows operated as if they were new, the furniture retro and even the doorbell was original. A memorable inspection indeed.

Anyways, I originally pegged it as a gravity and from the basement it would appear that way but more surprise was to follow. The caregiver for the gentleman (an electrical engineer) mentioned that it had a fan in the attic.

Sure enough, when I opened the hatch access this is what I found....the fan cabinet wraped in blue SM Board.

Download Attachment: icon_photo.gif FurnaceFan1_S.jpg

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This photo is what I found around the corner.

Download Attachment: icon_photo.gif ChimneyDamper_S.jpg

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There's one more unusual find that has me equally puzzled. Later


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I like the idea. This thing is heating the entire mass of the chimney and with todays controls like anticipators, I bet it'd be a very efficient unit. I'd like to look down the chimney and view the exhaust path, but my guess is it's an indirect path guiding the hot exhaust into a lot of contact with the masonry. There's probably a liner and an outer shell to blow the house air through and the energy stored in all that mass would radiate into the home after the burn is complete. It probably works like a heatilator fireplace. I'm guessing at all this so I reserve the right to be referred to as "full of shite".

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I reported the data plate information and called it a gravity gas furnace with fan assist located in attic.

What I'm researching is the history, and the design aspect of this animal. I wonder how long they were on the market and why are there so few of them. Did the company go out of business?

Incidently, I opened the 'awning' inspection hatch at the burners and the inside looked new..honest.

It's a puzzle.

I thank everyone for your help.

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I should have done that. Woodinville is about 4 miles as the crow flies from where I'm sitting.

Used to be a little hole-in-the-wall town when I first moved here. The town put together a development plan and put it into action around 1998. The whole downtown area has been transformed really nicely. Big new shopping centers with a sort of small village feel and houses going up everywhere. I bet the population over there has more than quadrupled.

Whoops, I'm rambling about non-HVAC stuff. Sorry, I just find the transformation of that place fascinating(Wish they'd do it here.).

I'll see what I can find out.



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That's really good information, cause I phoned the number given and it appears to belong to a woman.

I've done a yellow page search and no luck. I couldn't find an HAVC contractor in the town. It leads me to believe that it could have been an industrial center at one time.

Still searching

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Well, I talked to their downtown Seattle number this morning. They guy that talked to me said that he's worked for them for over 20 years (closer to 30) and had no idea what the hell I was talking about. My guess, they dallied in it for a very short period of time and perhaps sold their interest to the present company, which primarily sells HVAC components. I'll keep digging though. Maybe there is an old fellow around here that knows more than the guy downtown did.

OT - OF!!!


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