Location: latitude 47 N.W. montana zone 6A
posted 2 years ago
Hi All; Been a strange year weather wise here in the nw. Spring came early, but I found myself lighting the rmh off numerous times in may/june and even a few early mornings in july ! Normally I would have cleaned out the ash pit on the rmh long before now. A little backround on my rmh. It is located in a 12x20 plastic greenhouse/artist studio. During the winter this stove is kept running from 6 am thru 9 pm every day,to keep the building 40-70 F all night long .The first year I had a rmh I used a walker style cast core, super hot, super fast and after an entire season of heating , I removed 1/3 of a 5 gal bucket of fly ash with no buildup in the horizontal piping. Second year I switched to a firebrick core. Unfortunately I built it with a way to long burn tunnel and a not tall enough riser ... about late feb that year found me doing a big ash cleanout... ash pit full to the brim and all 20+' horizontal pipe was over 1/2 FULL !!! Needless to say it wasn't drawing very well at that point. A few days later we got a warm spell and I did emergency surgery on the core. Shortened the burn tunnel 5". This helped quite a bit (cleaning the ash out helped more ) but I was still not happy with its performance. That spring when i did my ash cleanout even with only a few months of burning I cleaned out 1/2 bucket of ash !!! way to much for just a few months ! Last year I did a complete core rebuild . All heavy firebrick, shorter burn tunnel , new taller cast riser , new surround with insulated castable inside. Performance this winter has been very good, no abrasion issues in the feed tube . Barrel temps averaged 600-800 F on top. Big question for me was how much ash buildup do I have Today, I opened it up for a look . Not to bad... ash pit was full ,but not heaping. Horizontal pipe had a fair amount for the first few feet ,then hardly any at all after that ! I'm happy with this. If I had cleaned it out in april like normal i'm sure that there would have been no ash in the pipe at all . This rocket burns way more than the average rmh, using just less than 5 cords from sept - april or june to keep a plastic greenhouse warm thru a western montana winter. The two seasons before building a rmh ,we burned 12-15 cords each season to do the same job ! Yes rocket mass heaters live up to all the claims and then some !