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.