Post by brett on Feb 15, 2014 13:19:46 GMT -8
Hello RMH experts,
I have been posting on Permies.com for a while and ran into a problem that I thought an expert here could help me solve.
I am building a rocket mass heater in a typical suburban home: central HVAC system in house, water heater in garage, house vents in kitchen - bathrooms, well sealed doors and windows, concrete slab.
Dimensions:
combustion chamber - 29 in^2
Currently have a heat riser that is 32 inches tall, 64 in^2
4 inch gap between top of heat riser and barrel
heat riser is offset inside the barrel
8" gavanized ducting
8" ducting T at the base of the RMH for the ash collection pit
~40' ducting run including external chimney
(4) 90 degree bends
air diffuser on top of chimeny
Here are some image links of the project:
During construction and layout
i1337.photobucket.com/albums/o665/daimyo505/09_ducting_layout_zps96e18255.jpg
Current setup for testing
i1337.photobucket.com/albums/o665/daimyo505/70_RMH_test_setup_zps126a68c3.jpg
Chimney leaving the fireplace ash dump
i1337.photobucket.com/albums/o665/daimyo505/50_chimney_out_ash_dump_zps8cea8737.jpg
Dual chimney setup with homemade air diffuser
i1337.photobucket.com/albums/o665/daimyo505/49_a_tale_of_two_chimneys_zps2e6c579b.jpg
RMH runs great when there is no wind. I usually warm the heat riser and system with a propane torch for 5 to 10 minutes and use an incense stick to check to make sure I'm getting a draft into the RMH. I have run tests with a door open and all doors and windows closed.
Problems you might be able to help me with:
*When the RMH is cold I have air backflow into the house
*When the RMH is running I have a leak around the second cleanout port that will vent into the house (I've been told that this should not be the case as there should be a negative pressure in the entire system). I've plugged the leak but believe I should have negative pressure in the RMH.
*When it is windy outside and RMH is hot I will get good positive draft (0 to 10 mph), but when a really gust breeze hits the flow direction will reverse and I will get backflow into the house and a face full of smoke.
Thanks in advance for you help!
I have been posting on Permies.com for a while and ran into a problem that I thought an expert here could help me solve.
I am building a rocket mass heater in a typical suburban home: central HVAC system in house, water heater in garage, house vents in kitchen - bathrooms, well sealed doors and windows, concrete slab.
Dimensions:
combustion chamber - 29 in^2
Currently have a heat riser that is 32 inches tall, 64 in^2
4 inch gap between top of heat riser and barrel
heat riser is offset inside the barrel
8" gavanized ducting
8" ducting T at the base of the RMH for the ash collection pit
~40' ducting run including external chimney
(4) 90 degree bends
air diffuser on top of chimeny
Here are some image links of the project:
During construction and layout
i1337.photobucket.com/albums/o665/daimyo505/09_ducting_layout_zps96e18255.jpg
Current setup for testing
i1337.photobucket.com/albums/o665/daimyo505/70_RMH_test_setup_zps126a68c3.jpg
Chimney leaving the fireplace ash dump
i1337.photobucket.com/albums/o665/daimyo505/50_chimney_out_ash_dump_zps8cea8737.jpg
Dual chimney setup with homemade air diffuser
i1337.photobucket.com/albums/o665/daimyo505/49_a_tale_of_two_chimneys_zps2e6c579b.jpg
RMH runs great when there is no wind. I usually warm the heat riser and system with a propane torch for 5 to 10 minutes and use an incense stick to check to make sure I'm getting a draft into the RMH. I have run tests with a door open and all doors and windows closed.
Problems you might be able to help me with:
*When the RMH is cold I have air backflow into the house
*When the RMH is running I have a leak around the second cleanout port that will vent into the house (I've been told that this should not be the case as there should be a negative pressure in the entire system). I've plugged the leak but believe I should have negative pressure in the RMH.
*When it is windy outside and RMH is hot I will get good positive draft (0 to 10 mph), but when a really gust breeze hits the flow direction will reverse and I will get backflow into the house and a face full of smoke.
Thanks in advance for you help!