Heater problems in a 200 Sq Ft camp. Your input is desired.

[satamax]

If you want your heater to warm up more, try blocking the top exhaust, use only the bottom.

[aefriot]

I do want the heater to get hotter, but something is still making it not burn cleanly. It still is smoking. possibly the primary air. Will wait and see.


Pre-fire

November 4, 2018, 08:15

Temperatures are as follows:

Item	F	C
Reference post (building temperature)	63	17
Outside temperature	34	1
Top of riser skin	75	24
Bottom of riser skin	75	24
Right cook top	73	23
Left cook top	70	21
Left side of heater (Double skin)  2.25" (114 mm) fire brick double thickness cardboard 3.5" (89 mm) natural stone	78	26
Left side oven	98	37
Middle of oven	85	29
Bottom of oven	88	31
Right oven side/Left side of fire box	92	33
Right side of fire box	89	32
Right side of heater (Single skin) 3" (76 mm) natural stone	75	24
Back of heater behind fire box (Double skin) 2.25" (114 mm) fire brick 1" (25 mm) air space double thickness cardboard 5" (127 mm) natural stone	77	25

Wood loaded:
2/3 load soft wood building scraps slightly damp 13-37% surface moisture as wood sat outside and was rained upon. Been inside for a week.


Post-fire

12:15

Temperatures are as follows:

Item	F	C
Reference post (building temperature)	81	27
Outside temperature	42	6
Top of riser skin	184	84
Bottom of riser skin	179	82
Right cook top	177	81
Left cook top	150	66
Left side of heater (Double skin)  2.25" (114 mm) fire brick double thickness cardboard 3.5" (89 mm) natural stone	103	39
Left side oven	213	101
Middle of oven	205	96
Bottom of oven	158	70
Right oven side/Left side of fire box	190	88
Right side of fire box	310	154
Right side of heater (Single skin) 3" (76 mm) natural stone	114	46
Back of heater behind fire box (Double skin) 2.25" (114 mm) fire brick 1" (25 mm) air space double thickness cardboard 5" (127 mm) natural stone	94	34

Pre-fire

Camp door was open most of the day. We worked on the kitchen area and let a lot of cooler air in.

20:30

Temperatures are as follows:

Item	F	C
Reference post (building temperature)	67	19
Outside temperature	30	-1
Top of riser skin	83	28
Bottom of riser skin	83	28
Right cook top	80	27
Left cook top	79	26
Left side of heater (Double skin)  2.25" (114 mm) fire brick double thickness cardboard 3.5" (89 mm) natural stone	77	25
Left side oven	95	35
Middle of oven	82	28
Bottom of oven	84	29
Right oven side/Left side of fire box	95	35
Right side of fire box	97	36
Right side of heater (Single skin) 3" (76 mm) natural stone	74	23
Back of heater behind fire box (Double skin) 2.25" (114 mm) fire brick 1" (25 mm) air space double thickness cardboard 5" (127 mm) natural stone	77	25

Wood loaded:

Full load soft wood building scraps slightly damp 13-37% surface moisture as wood sat outside and was rained upon. Been inside for a week.

[peterberg]

Use bone dry fuel, moist will take up an enormous amount of power. In general, a level above 25% moisture will take up around 40% of the potential energy. All that water need to be evaporated before the temperature of the fire can significantly rise above 100 ºC, boiling point of water. In order to get to boiling point one would need a lot of energy. Once it is evaporated, a little energy will keep it in that state.
See the example of a kettle of water on a gas burner: a quite substantial amount of time to get it to the boil at high fire, to keep it on the boil just turn the burner to low.

[aefriot]

I opened the hole up in the steel plate for the primary air this morning. I figured the heater wasn't operating efficiently and maybe it was because it wasn't breathing properly. I started a fire with the same damp construction scraps I have used before.

Yes, Peter you are right. Dry wood makes a large difference and I am using a lot of the woods' potential energy just drying itself to keep the fire burning. The fires I have been recording have only been for heating and not cooking, but still, I'm wasting energy drying the fire wood in the fire box. If it were a month earlier, I would have plenty of really dry wood. Unfortunately, it's rained nearly daily for the last month drenching my supply of dry wood. I have been so busy with this and other projects I have neglected my wood storage. I do have some cherry scraps in the workshop I can fill the fire box the next fire I start. Those should be about as dry as wood can get if it was air dried. I can then compare damp soft wood and dry hard wood temperatures.

As I write this, I looked at the front of the heater and saw water dripping from the bottom of one of the panels. I opened the oven door to be met by steam to fog my glasses and just a little smoke smell (smell only, no visible smoke). This is a good sign! Previously, when I opened the door, smoke billowed out to fill the air. Opening the primary air up to nearly twice what I thought would suffice (coming from a traditional wood stove) has allowed the heater to take in enough air to burn hotter. Hot enough to burn much cleaner than before, even with damp wood. I looked at the chimney to see steam vanishing into the air instead of smoke drifting away to the neighbors.

Tonight, I look forward to burning the dry cherry to see what temperatures may exist in (and on the exterior surface) our heater.

Cherry also has 32% more BTU than the pine or spruce I have been burning ( According to Chimney Sweeps Library ).

[aefriot]

Too warm tonight for a hot fire. It's 45*F (7*C) outside and still 70*F inside from this mornings' fire. I'm lighting a small fire to keep the heater warm though the night without getting too warm. We are really liking this mass heater stuff. I'll get the cook surface to where we can use it, I just have to tweak the heater or perhaps add a little rocket for meal time use. Maybe adding heat sinks to the underside of the cook top or add insulating trivets that can be removed for cook top access. I'll continue working on it and posting progress...or regress.