GreenWood
furnace
Feb. 24th, 2oo7


This is a temporary out door in the weather installation of a GW100 (1oo,ooo BTU) furnace.


The GW is NOT a boiler. It is un pressurized thus uses a reservoir seen laying down in top of the furnace in the above foto. The reservoir is normally mounted vertically  on a wall next to the furnace with a line leading to the rear of the furnace.

The GWs use an Flat Plate Heat Exchanger mounted on the back of the furnace so the unit can transfer the furnace's  heat to the circulating loop that supplies hot water to the home.

I suspect doing it this way allows the GW to:
a.    Keep the corrosive acids of low PH water lower in the furnace.
b.    Allow the structure to be heated at a higher location than the furnace.
c.    Keeps the house's cold return water from damaging the furnace.
 
 

The GW furnaces are basically just a big pot of  hot water heated by wood. In my two cents, nothing wrong with this. In actuality it may make the furnaces easier to certify because they can not over temp. and blow up. This should cost the manufacture less in certification costs and as long as this is passed along to the consumer this is a good stradigity.


This is Mr. Robert Lee, the local dealer for GreenWood furnace in my area. Candidly Mr. Lee lives in a lovely area, however, it is quite off the beaten path. It was not only a long drive, it was perhaps 20 miles or so back in real rural Pennsylvania. Personally I enjoyed both the drive n new roads to explore. I even intentually took a different way home just for the challenge n scenery. But suspect many a potentially buyer will be put off by the out of the way location.


As I mentioned earlier, this is a temporary installation - hoses through the wall with what seems like automotive radiator hose (seen above). Mr. Lee's original GW200's heat exchanger sprung a leek either due to poor steel and or to low of PH in his water. Pennsylvania is notorious for low PH water in many spots. I did ask Mr. Lee what his PH was, he did not know. So this vary early rust out could be 100% not the manufacture's fault. The GW does say they have a 10 year guarantee.


The fire box of  the smallest GW is BIG 8.4 cubic feet.  No need to split wood, just dump a few chunks in.


Nice BIG fire box like I said earlier with a 18" X 16" door that is lined with 3 - 4" thick refractory cement cast blocks that also should hold a lot of heat.

Above n below are photos taking looking up at the heat exchange tubes through the open door. Seems the only way to clean off the tubers if to reach in side with a long handle brush. Seems all the grey stuff is ash and the back is the individual tubes.

Above n below are the same foto showing the heat exchange n manifold system of the GW200. The below foot is an enlargement of the area that developed a hole and the reason for the smaller GW100 being installed out in the weather as seen in the opining foto.

The above photo was take of the stack with the combustion intake air door closed. Not too much smoke, which is actually un combusted fuel wasting away out of the chimney it seems both times I asked Mr. Lee to damp her down.

Below is a foto of the combustion air inlets, 4 of  them on the GW100 and the damper which actually is a motor accuated flapper valve. When the power fails, the damper system is designed to automatically close off most of the air entering the GW furnace.  Also, the combustion air is pre heated by the exhausting flu gasses before entering the combustion chamber.

All in all I enjoyed meeting n chatting Mr. Lee and I liked the furnace. Only time will tell if this is the one I end up investing my hard earned money in.




Pros:
a.    Continual burn, no need to re start a fire each day as in many/all of the wood gasification boilers with big water tanks for heat storage I have seen so far.
b.    Symple but effective controle system.

Cons:
a.    Over all cost $8,ooo by the time tax, shipping n accessories are paid for.
b.    No Ash pit door.
c.    Shipping costs due to the 2300+ weight.
d.    Smokes some when the door is open. GW does not provide an alternative/easier path option for the exhaust gas to exit the down draft chimney when the open door.  I would not suggest in door, basement or closed garage installation.
e.    No secondary combustion chamber that seems to be in other wood gasification boilers.
f.    Air intake tubs seemed to be a tad flimsy n one was gummed up with a alarming amount of  creosote. I honestly wonder if they will end up being the weak link in the chain.
g.    No gasket on furnace door.

Tarm

GreenWoood

Keystone Stoker

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