Monday, October 29, 2007

Go Heatmor Go!

The following is a recounting of the final three days of heat system installation. Yes. On the eve of the first frost, our home was warm.


Thursday night, a bit rainy and all that, we installed the domestic coil in the back of the furnace. I had been apprehensive about this job since it entailed cutting into a gasket at the back of the heat jacket and I figured this would be precision work that would need to be done right the first time. It wasn't so bad, as it turned out. With a bit of prying, the rear cover came off and a solid rubber gasket was revealed. I scratched the date into it then cut away the center.

I looked into the furnace and understood it much more. There's the fire box, which is what you build the fire in, and then the rest of the furnace will be filled with water. A big box of water with a big fire box in the middle of it all. Neat. We put a bead of silicone around the gasket and inserted the copper coil. Then we tightened the brass fittings on and connected the water lines to it.


Friday night, Erika's dad arrived and we made an awesome dhal and I tried out a tandoori chicken recipe that killed and we ate and drank until late, when we decided to take a hike up the trail to the back corner of the property in the pouring rain. We stayed up there for a while, it was like being in another place entirely. It was great, and we were soaked.


I started off helping Erika and Marty with the shed a bit, but eventually realized that if we wanted to get the heating fired up this weekend, I'd have to get to work on finishing the installation.

First, I had to secure the furnace to the concrete pad. I drilled four holes into the concrete just beside the base of the furnace and pounded some concrete anchoring bolts into the holes. I used a couple of large washers to sandwich the base of the furnace to the pad, and ended up using small chunks of soapstone as a fulcrum for the other side of the washer. The anchors took some adjusting, but in the end the furnace was shimmed and clamped tightly to the pad.

Second, I had to caulk the based of the furnace, inside and out. This is pretty self-explanatory. Done.

Third, I had to pack masonry (brick) sand all inside the fire box until it was level with the grates. We had some brick sand left over from when we made the grout for the bathroom floor but that didn't get me too far. I found a couple of cardboard boxes and drove down to the hardware store and parked the car around back by the sand pile, shoveled all I could fit into the boxes: 34 shovel fulls. This ended up being about half as much as I would need, so I ran back for another 34 shovels. On the way down the road, the car stopped running and wouldn't start. I was able to diagnose it pretty quickly - blew the fuel pump fuse somehow. I swapped the heater fuse for it (irony) and was on my way. That was the last run for sand. I packed it in and we were now sanded and ready for filling the furnace with water.

Fourth, I filled in the rest of the trench by the house.

I pitched in with the shed project for the last hour or two of the afternoon. We quit shortly before dark.


We were up and outside at dawn. After a cup of coffee, I got ready to fill the Heatmor (furnace). Opened and shut the appropriate valves, read, read, and re-read the instructions, then turned on the water. I was surprised by how much water this thing takes. It filled for at least ten minutes before finally coming out the top from the pressure release vent. I cut the water source and opened up another valve in the furnace and the water rushed through the underground pipes to and from the house, filling them and pushing the remaining air out of the system. I filled the expansion bladder and topped it off through the relief vent on the roof of the furnace.

There were a couple of little seeping leaks - one at the back of the furnace, and one at the pump in the basement, but I tightened 'em up and they looked good.

I built a little structure of newspaper, twigs, and small logs inside the furnace. When the shed crew got to a good stopping point, we gathered around the furnace and I lit it up. Hooray! Smoke started coming out the chimney. After the little fire got going, I shut the door and turned on the fan. Ten minutes later, I loaded it up with wood and we were good. The water temperature began to rise.

It was around 11AM when we lit it. It took a couple of hours for the water temperature in the furnace to reach 180 degrees. Once it did, the shed crew took another break and we all went down to the basement to click on the rest of the system. We turned on the circulator pump for the furnace and hot water began flowing from the furnace and through the heat exchanger, which heated up at an fascinating rate. Erika then set the floor temperature and the radiant pump clicked on and began circulating through the house. Again, hooray!

Then it was pretty much all shed for the rest of the day. Of course, I was constantly taking system and temp readings at the furnace, at the supply manifold, the return manifold, the mixing valve, the pressure, the floor temp, and the ambient temps. Everything was functioning perfectly.

It was clear by five or six o'clock that our house was definitely warm. This was amazing to me, since there are still a few joist bays in the basement that need to be insulated, and the kitchen roof/ceiling is totally uninsulated and our bathroom doesn't have a real window.

We stacked our first load of wood by the warm smell of the wood stove. I loved every minute of it and have been looking forward to doing this for years. This first load is mostly small pieces of wood. We've got a load coming right behind it with bigger logs. Once we get ahead of ourselves, we can get out into the woods and start bringing home the big downed trees out there. This fire can handle large, unsplit logs, as big as you can fit into its mouth. It just dissolves these little guys.

All night long, the temperature outside was dropping. Before we went to bed, it was 42 degrees outside. It was cozy in our home. I couldn't stop talking about it. Couldn't stop looking at the temp outside. We have a wicked system. And just in time for the first frost, which came several hours later.

- John


Anonymous said...

Hey Guys, ran across your blog while researching Heatmor wood boilers. How happy are you with it after a winter?

I noticed a lot of smoke in one of your pics. I've heard that some of these boilers generate a lot of smoke. Can you give me the smoke scoop on your heatmor? Many thanks!

Interesting blog!

Bob Deering (deering at ak dot net)
Juneau, Alaska

John & Erika said...

hi Bob, thanks for stopping by!

we're very satisfied with our heatmor. the smoke you see in that picture was from the first time we lit it up - we really had a lot to learn at that point! I think it took us a couple of hours or so that day to get the water up to temp. by the time we were full-swing in winter, I could get a fire going in there and bring the water up to 180 in a half hour or less. once you get the feel for these things, the system is very consistent, predictable, and satisfying to operate.

if used properly, there is really very little smoke involved. once the fire is lit and burning hot, there is no smoke, just clear-looking heat vapor. once the water comes up to temperature, the fire chokes out and there is just a little bit of smoke coming from the chimney for a few minutes. when the water temp drops and the blower kicks back on, there is some smoke again until the fire gets hot, but not a lot of smoke. all in all, there's far less smoke than the typical indoors wood furnace we see around town.

we use seasoned wood and load for 12 hour intervals. we also keep a 15-20 degree variance between hot and low cutoff temps. we get a pretty clean and complete burn with very little smoke. most of the problems/complaints I've read about are a result of people using poor fuel, or not operating the furnace properly/responsibly.

wood is a locally-obtainable, carbon-neutral, and renewable resource; far less impact and far less pollution than mining/refining/transporting/delivering non renewable fossil fuels such as oil, coal, and natural gas.

good luck :)


Anonymous said...

I have had a Heatmor for 1 season now (will be starting my 2nd season here in 2008). My biggest complaint, is I would like to see Heatmor and other manufacturers of OWB's start a rebutle against all these tree huggers that are trying to ban these units. If yo search the internet, the only thing you will find are the enviroweenies distorting the facts!
We shouldnt be waiting for another round with the EPA to get defensive. We should be on OFFENSE!

John & Erika said...

Actually, we consider ourselves tree-huggers and environmentalists and that's one reason we chose the Heatmor--it uses a local, renewable energy source.

The issue of banning them isn't simple. Maybe they're not appropriate in denser places like towns and cities, but we, like you, would hate to see them banned altogether. However, we'd be pretty unlikely to join forces with somebody who threw out a term like "enviroweenies." It belittles a lot of hard work we do to make our house more efficient.

Anonymous said...

Our Heatmor has been going now for 24 hrs. I enjoyed reading your blog! a lot of it sounds like us.
My quetion to you is "What is the proper way to open the door?" 1. Switch off...wait a minute open door. 2. Open door a crack first..switch off then open door.
One of the installers told me one way and the other man told my husband the other way. Just curious.

John and Erika said...

The correct way is to first shut off the fan, then crack the door an inch or so, and wait a little bit. I never wait a full minute, usually about 15 seconds, but it depends on the fire.

Do not open the door while the fan is running! You'll get a face full of smoke or worse, a face full of fire. Always turn the fan off before the door is opened.

It's best not to open the door during the combustion stage (that is, when the fan is running) if you can help it, for the sake of efficiency.

Thanks for reading!

Anonymous said...

Did you use glycol in the system or just straight water? The system looks great, could you tell me, ballpark, what a system like this would cost me? I am building a new home on a quarter section in Saskatchwan, Canada.

Judy said...

Just got my new heatmor and am already saving money. Yes it smokes, but not as steady as my inside woodstove did. No more wood smoke in my house now. Come to think about it, its 0 outside and if i go outside and breath, it looks like i am smoking...Love it and so far no regulations in my town and they can make new laws but I am protected by the grandfather law now!

Anonymous said...


I've hade my Heatmor for four years. I now hear gurgling and realize the bladder needs topping off.
Two questions:
Do you add the fluid through the vent with the rubber ball stopper next toi the chimney ? I wasn't home when this was originally installed.
Second, what raito of water to antifreeze do you use ?


Anonymous said...

Looks like its been a while since you've had comments on this site. Good pictures. Question - I have an indoor wood furnace. I figure my indoor furnace may be somewhat more efficient than an outdoor furnace. The furnace heats the air and it heats the house. An outdoor furnace heats the water is pumped through the ground to the house and then the water heats the air which will heat the house. Well on the way the water must be heating the ground and an outdoor structure out there in the cold must have quite a lot of heat loss. So - How much more wood do you burn in an outdoor wood furnace as compared to an wood indoor furnace? I like the idea of only two fills a day and so am in the beginning stages of thinking of getting one of these.


John and Erika said...

Hi Clarence -

We've never had an indoor furnace at the house, just the OWB, which I find to be an efficient machine. I'm sure there is some heat loss as the travels from the furnace to the house, but it has no effect on our heating system. The water leaves the furnace at about 180F, and the max water temp recommended for our hydronic heating tubes in the house is only we actually have to cool the water even further.

An indoor furnace would not make sense in our small house. Space is at a premium. I also like that the radiant floor heat system that we installed provides a constant and even heat. There are no cold spots, and it doesn't blow air (and dust) around. Also, compared to an indoor furnace, we can burn pretty much any kind of wood. We burn lots of pine and poplar and sycamore, which is wood that most people throw away...which works out good for us. The outdoor furnace also heats our domestic hot water during the heating season.

Two fills per day is a nice thing. Of course, it depends on the wood we're burning and the weather.

Mike Carter said...

Thanks so much for sharing this information. I got an indoor wood furnace this past winter and it suited my house very well. It got me through a pretty harsh winter.