# NEWMACK Combination furnace - smells of smoke in the house



## hplanas (Dec 29, 2013)

I just purchased a new home that has a Newmack combination furnace (oil, wood,coal) from 1978. The previous owner heated the house partially with coal and  wood. I became very excited one day and decided to try to use it with wood. After watching  many videos on youtube, I decided to give it a try. I turned up the woodburning dial to start the fan, opened the air blower to the middle setting. I also opened the vent at the bottom to allow more air to flow in. I loaded  the chamber with wood little by little  as the fire started. Everything was great but I noticed that in some rooms of the house, there was a smell of smoke. Alarmed I placed the CO2 detector in these areas to ensure that the levels were OK and the alarm never was set. Yet,  I am not certain if there should be smell in the house when using a woodburning furnace. Is this ussual? Does anyone have any suggestions? Any videos or books or websites that I should be viewing? Please help!


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## webbie (Dec 29, 2013)

Lots of possibilities as to where the bit of smell can come from.
Make sure you find and download a manual. Newmac may have one
http://newmacfurnaces.com/index.php/homeowners-products-3

Smoke smell could come from lots of places. Part of the furnace pipe and heat exchanger goes through the return air inlet - as in the drawing below. If that has a slight leak in it or even a tiny bit of creosote leaking (the size of a fingernail could smell a lot), then you will get a smell in the house. If the return air is pulled from the basement - and some smoke spills when you load, the same thing could happen. Make sure the stovepipe is very tightly connected and cemented where first contacts the furnace.


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## brenndatomu (Dec 29, 2013)

Any idea what your chimney draft like? Weak draft will cause smoke smell problems. Could be something simple like a bathroom or kitchen fan running (or clothes dryer), causing poor chimney draft.
Just FYI, do a search here on hearth about the Newmac. There is quite a bit of info around here on them. Some interesting threads about increasing efficiency too.


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## Fred61 (Dec 29, 2013)

In the early days of the oil crises there was a heating contractor around here that installed several of these Numacs. The first thing people had to learn  was if they were going to burn wood they needed to cover the coal grates with a sheet of steel or something solid. The next most important thing was not to use the combustion fan. The units leaked more than enough air to keep the fire going. One other procedure was to only load small amounts of wood at a time otherwise the whole load will catch and severely overheat the house for a short period of time and burn itself out if you don't reload. They're not known for holding a fire overnight.


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## maple1 (Dec 29, 2013)

I would have serious reservations about running a 35 year old Newmac - you could be setting yourself up for some deadly CO poisoning from a corroded firebox. 35 years is a loooong time for one of those.


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## laynes69 (Dec 29, 2013)

This post made me cringe a little. I'm with Maple. Diving into a furnace that old is risky, even if it was used by the previous owners. Before firing a unit that old, I would remove the jacket and inspect things. Chances are everything could be okay, but I wouldn't assume anything. Not only do you have the body to be concerned with, but the electrical components themselves.


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## hobbyheater (Dec 29, 2013)

Furnace of the same vintage 35 years old. Wood smoke and oil fumes throughout the house.
Cause was a big crack in the heat exchanger.
Be cautious!


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## MacYoung (Jan 1, 2014)

We have a Newmac wood / oil combo that must be at least 30 years old. We heat our 1700 sq ft house mainly with wood.  There are lots of similar Newmac furnaces in our area.  They seem to last for many years if well maintained.  

One of my complaints is that we have a lot of smoke escape into the house while loading wood into the furnace.  I run the inducer fan wide open all the time to improve the combustion, but we likely are losing efficiency.  I notice a lot more smoke when the inducer fan isn't running. 

I'm interested in hearing from others who have suggestions to improve the performance of these furnaces. This is my first posting after following the forums for several years.


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