Installing the Walltherm

The Walltherm is the centre showcase of the Flatrock Passive House heating system.  As mentioned in previous posts, it is a gasification boiler.  With a efficiency of 93% (LHV), it dumps about 12.5 kW into hot water while only 2.5 kW is emitted to the room (specifications with the Quick Insulation kit installed.).  It took 4 of us to move it with a hand truck into the living room (Photo 1).  With the wall thimble already in place (Photo 1) it there was only one place for it to go.  However, limitations in the lengths of double wall stove pipe made the placement a little challenging. This being said Excel ULTRABlack  manufactured by ICC (Purchased locally from Emberly Fireplace) comes in a variety of different lengths, and they also have slip lengths to accommodate many set ups so we placed the stove so that the back was 10" to the wall (minimum offset to combustible according to the manufacturer).  Excel ultra black lengths were chosen so that the setup would work.  Photo 4 shows the final stove pipe configuration.

With the stove in place (Photo 3) it was time to plumb in the various connections.  Adam Rickert was on site to do the connections.  The connections include a supply and return from the tank, a thermostat that turns on and off the pump group, a temperature gauge, manometer, etc.  One issue we ran into with the stove is that the threads are made for European fittings.  Although NPT threads fit fine, they bottom out completely once tightened and since they are mating with a non tapered fitting.  The fittings required large amounts of teflon and leak lock to seal adequately and the results weren't fool proof.  Multiple attempts to pressurize the system with air pressure presented leaks between mated fittings.  A local company, Island Hose and Fittings, carry dowdy seals (bonded seal) that are meant for this application.  A bonded seal is really just a washer with a rubber seal bonded to the center hole of the washer. We switched directions and used dowdy seals instead since they provide a more robust seal.  The system was pressurized and remained pressurized over a weekend so we felt that it was good to go for filling.  The system was filled with water from the well using the automatic refill connected to the tank.  It took almost 1.5 hours to fill the tank!  At 243 gallons plus the water needed to fill the distribution lines to each radiator, there is a lot of water!  The well didn't run dry so its a good sign that the well recovery flow rate recorded by the driller was probably pretty accurate.

With the installation complete, Its now time to test the system!

Photo 1.  Finally!  The Walltherm is in the Living Room!

Photo 2.  The thimble that was previously installed was trimmed around using clearances specified by ICC Chimney.

Photo 3.  Walltherm in its final location.

Photo 4. plumbing the various connections.

Photo 4.  Installing an automatic air vent on the Logix24 tank.

Photo 5.  Installation complete!  Ready for testing.


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